In order to prepare to emit KASAN checks in JITed programs, JIT
compilers need to be aware about whether some load/store instructions
are targeting the bpf program stack, as those should not be monitored
(we already have guard pages for that, and it is difficult anyway to
correctly monitor any kind of data passed on stack).

To support this need, make the BPF verifier mark the instructions
depending on whether they could access or not memory other than stack.
As different states in the verifier could lead to different memory types
for the same access, just marking an instruction as accessing stack only
is not enough (it could be some other memory type in another verifier
state), so the algorithm rather sets by default any load/store
instruction as stack only, and if _any_ state leads to any memory access
type other than PTR_TO_STACK, it overrides this setting. It also takes
care about shifting back the instruction marking in adjust_insn_aux_data
if the verifier patches instructions. However, if the verifier generates
new BPF_ST/BPF_STX/BPF_LDX while patching some instructions, those new
ones are systematically marked as non-stack-accessing: this may
over-instrument a few memory accessing instructions, but it allows
making sure that we will not miss accidentally any.

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v6:
- drop original instruction offset tracking, but add a best effort
  original insn marking preservation
- update comment style

Changes in v5:
- fix incorrect marking for single instruction patch

Changes in v4:
- include BPF_ATOMIC in is_mem_insn
- correctly mark instructions in adjust_insn_aux_data if patch generates
  a single instruction (ie replace an instruction)

Changes in v3:
- drop getter
- drop cBPF handling
- update marking shifting logic to track more precisely orignal
  instructions
- systematically mark newly generated instructions as non-stack
  accessing

Changes in v2:
- invert marking logic to cover possible different reg types when the
  verifier covers different states
- add a best-effort processing for classical bpf programs, inspecting
  directly src and dst registers since we don't have verifier env
- make sure to keep marking in sync with prog when it is patched by
  verifier
---
 include/linux/bpf_verifier.h |  2 ++
 kernel/bpf/fixups.c          | 45 +++++++++++++++++++++++++++++++++++++++++---
 kernel/bpf/verifier.c        |  9 +++++++++
 3 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 004b06785521..412a13a664fa 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -725,6 +725,8 @@ struct bpf_insn_aux_data {
 	u16 const_reg_map_mask;
 	u16 const_reg_subprog_mask;
 	u32 const_reg_vals[10];
+	/* instruction can access non-stack memory */
+	bool non_stack_access;
 };
 
 #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c
index 65b441e4a351..edcb0cbbb13d 100644
--- a/kernel/bpf/fixups.c
+++ b/kernel/bpf/fixups.c
@@ -208,12 +208,25 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env,
 }
 #endif
 
+static bool is_mem_insn(struct bpf_insn *insn)
+{
+	if (BPF_CLASS(insn->code) != BPF_ST &&
+	    BPF_CLASS(insn->code) != BPF_STX &&
+	    BPF_CLASS(insn->code) != BPF_LDX)
+		return false;
+
+	return (BPF_MODE(insn->code) == BPF_MEM ||
+		BPF_MODE(insn->code) == BPF_MEMSX ||
+		BPF_MODE(insn->code) == BPF_ATOMIC);
+}
+
 /* single env->prog->insni[off] instruction was replaced with the range
  * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
  * [0, off) and [off, end) to new locations, so the patched range stays zero
  */
 static void adjust_insn_aux_data(struct bpf_verifier_env *env,
-				 struct bpf_prog *new_prog, u32 off, u32 cnt)
+				 struct bpf_prog *new_prog, u32 off, u32 cnt,
+				 struct bpf_insn *original_insn)
 {
 	struct bpf_insn_aux_data *data = env->insn_aux_data;
 	struct bpf_insn *insn = new_prog->insnsi;
@@ -227,8 +240,15 @@ static void adjust_insn_aux_data(struct bpf_verifier_env *env,
 	 */
 	data[off].zext_dst = bpf_insn_def32(new_prog, insn + off + cnt - 1) >= 0;
 
-	if (cnt == 1)
+	if (cnt == 1) {
+		/*
+		 * A non-memory accessing insn could have been replaced by a
+		 * memory accessing insn, systematically mark it for non-stack
+		 * access
+		 */
+		data[off].non_stack_access = is_mem_insn(insn + off);
 		return;
+	}
 	prog_len = new_prog->len;
 	env->insn_aux_data_len = prog_len;
 
@@ -239,8 +259,25 @@ static void adjust_insn_aux_data(struct bpf_verifier_env *env,
 		/* Expand insni[off]'s seen count to the patched range. */
 		data[i].seen = old_seen;
 		data[i].zext_dst = bpf_insn_def32(new_prog, insn + i) >= 0;
+		if (!memcmp(insn + i, original_insn, sizeof(struct bpf_insn))) {
+			data[i].non_stack_access =
+				data[off + cnt - 1].non_stack_access;
+			data[off + cnt - 1].non_stack_access = false;
+		} else if (is_mem_insn(insn + i)) {
+			data[i].non_stack_access = true;
+		}
 	}
 
+	/*
+	 * Last slot instruction could be a newly generated
+	 * BPF_ST/BPF_LDX/BPF_STX, systematically mark it for non-stack access
+	 * if it is not the original instruction, otherwise keep the
+	 * original marking
+	 */
+	if (is_mem_insn(insn + off + cnt - 1) &&
+	    memcmp(insn + off + cnt - 1, original_insn, sizeof(struct bpf_insn)))
+		data[off + cnt - 1].non_stack_access = true;
+
 	/*
 	 * The indirect_target flag of the original instruction was moved to the last of the
 	 * new instructions by the above memmove and memset, but the indirect jump target is
@@ -306,6 +343,7 @@ struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
 {
 	struct bpf_prog *new_prog;
 	struct bpf_insn_aux_data *new_data = NULL;
+	struct bpf_insn original_insn;
 
 	if (len > 1) {
 		new_data = vrealloc(env->insn_aux_data,
@@ -318,6 +356,7 @@ struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
 		env->insn_aux_data = new_data;
 	}
 
+	memcpy(&original_insn, env->prog->insnsi + off, sizeof(struct bpf_insn));
 	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
 	if (IS_ERR(new_prog)) {
 		if (PTR_ERR(new_prog) == -ERANGE)
@@ -326,7 +365,7 @@ struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
 				env->insn_aux_data[off].orig_idx);
 		return NULL;
 	}
-	adjust_insn_aux_data(env, new_prog, off, len);
+	adjust_insn_aux_data(env, new_prog, off, len, &original_insn);
 	adjust_subprog_starts(env, off, len);
 	adjust_insn_arrays(env, off, len);
 	adjust_poke_descs(new_prog, off, len);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e036ae20bf6b..040af75d9550 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3272,6 +3272,11 @@ static void mark_indirect_target(struct bpf_verifier_env *env, int idx)
 	env->insn_aux_data[idx].indirect_target = true;
 }
 
+static void mark_non_stack_access(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].non_stack_access = true;
+}
+
 #define LR_FRAMENO_BITS	4
 #define LR_SPI_BITS	6
 #define LR_ENTRY_BITS	(LR_SPI_BITS + LR_FRAMENO_BITS + 1)
@@ -6654,6 +6659,10 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, struct b
 				clear_scalar_id(&regs[value_regno]);
 		}
 	}
+
+	if (!err && reg->type != PTR_TO_STACK)
+		mark_non_stack_access(env, insn_idx);
+
 	return err;
 }
 

-- 
2.55.0

Add a new Kconfig option CONFIG_BPF_JIT_KASAN that automatically enables
generic KASAN (Kernel Address SANitizer) memory access checks for
JIT-compiled BPF programs as well, when both KASAN (and more
specifically, generic KASAN with KASAN_VMALLOC) and JIT compiler are
enabled. This new Kconfig is not a user selectable one: it is
automatically enabled if KASAN is enabled on a compatible platform. When
enabled, the JIT compiler will emit shadow memory checks before memory
loads and stores to detect use-after-free or out-of-bounds accesses at
runtime. The option is gated behind HAVE_EBPF_JIT_KASAN, as it needs
proper arch-specific implementation.

Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v6:
- fix commit msg
- get rid of "if KASAN" when setting default value, already implied by
  KASAN_GENERIC

Changes in v4:
- reorganize dependencies (Andrey)
- drop VMAP_STACK dependency

Changes in v2:
- add dependency on kasan for vmalloc and vmalloc'ed stack
---
 kernel/bpf/Kconfig | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig
index eb3de35734f0..d7d25477ef48 100644
--- a/kernel/bpf/Kconfig
+++ b/kernel/bpf/Kconfig
@@ -17,6 +17,10 @@ config HAVE_CBPF_JIT
 config HAVE_EBPF_JIT
 	bool
 
+# KASAN support for JIT compiler
+config HAVE_EBPF_JIT_KASAN
+	bool
+
 # Used by archs to tell that they want the BPF JIT compiler enabled by
 # default for kernels that were compiled with BPF JIT support.
 config ARCH_WANT_DEFAULT_BPF_JIT
@@ -101,4 +105,17 @@ config BPF_LSM
 
 	  If you are unsure how to answer this question, answer N.
 
+config BPF_JIT_KASAN
+	bool
+	depends on HAVE_EBPF_JIT_KASAN
+	depends on KASAN_GENERIC
+	depends on KASAN_VMALLOC
+	depends on BPF_JIT
+	default y
+	help
+	  Makes JIT compiler insert generic outline KASAN checks in BPF
+	  programs when they are inserted in the kernel. This feature is
+	  automatically enabled if the needed set of KASAN and BPF
+	  configuration options is enabled.
+
 endmenu # "BPF subsystem"

-- 
2.55.0

In order to prepare for KASAN checks insertion before every
memory-related load or store, group all BPF_ST instructions that indeed
access memory in a single helper to allow instrumenting those in one
call, rather than having to instrument all cases individually.

Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v7:
- align dst_reg type with same type as other emit helpers
- fix line wrapping
- add missing doc on top of new helper
- remove unneeded cast

Changes in v3:
- new patch
---
 arch/x86/net/bpf_jit_comp.c | 98 +++++++++++++++++++++++++++------------------
 1 file changed, 59 insertions(+), 39 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 48429fae0641..13ba3232993a 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1315,6 +1315,63 @@ static void emit_st_index(u8 **pprog, u32 size, u32 dst_reg, u32 index_reg, int
 	*pprog = prog;
 }
 
+/* ST: *(u8*)(dst_reg + off) = imm */
+static void emit_st(u8 **pprog, struct bpf_insn *insn, u32 dst_reg,
+		    s32 outgoing_arg_base, u16 outgoing_rsp)
+{
+	s32 imm32 = insn->imm;
+	u8 *prog = *pprog;
+	s32 insn_off;
+
+	switch (BPF_SIZE(insn->code)) {
+	case BPF_B:
+		if (is_ereg(dst_reg))
+			EMIT2(0x41, 0xC6);
+		else
+			EMIT1(0xC6);
+		break;
+	case BPF_H:
+		if (is_ereg(dst_reg))
+			EMIT3(0x66, 0x41, 0xC7);
+		else
+			EMIT2(0x66, 0xC7);
+		break;
+	case BPF_W:
+		if (is_ereg(dst_reg))
+			EMIT2(0x41, 0xC7);
+		else
+			EMIT1(0xC7);
+		break;
+	case BPF_DW:
+		if (dst_reg == BPF_REG_PARAMS && insn->off == -8) {
+			/* Arg 6: store immediate in r9 register */
+			emit_mov_imm64(&prog, X86_REG_R9, imm32 >> 31, imm32);
+			*pprog = prog;
+			return;
+		}
+		EMIT2(add_1mod(0x48, dst_reg), 0xC7);
+		break;
+	}
+
+	insn_off = insn->off;
+	if (dst_reg == BPF_REG_PARAMS) {
+		/*
+		 * Args 7+: reverse BPF negative offsets to
+		 * x86 positive rsp offsets.
+		 * BPF off=-16 → [rsp+0], off=-24 → [rsp+8], ...
+		 */
+		insn_off = outgoing_arg_base - outgoing_rsp - insn_off - 16;
+		dst_reg = BPF_REG_FP;
+	}
+	if (is_imm8(insn_off))
+		EMIT2(add_1reg(0x40, dst_reg), insn_off);
+	else
+		EMIT1_off32(add_1reg(0x80, dst_reg), insn_off);
+
+	EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
+	*pprog = prog;
+}
+
 static void emit_st_r12(u8 **pprog, u32 size, u32 dst_reg, int off, int imm)
 {
 	emit_st_index(pprog, size, dst_reg, X86_REG_R12, off, imm);
@@ -2250,49 +2307,12 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 			EMIT_LFENCE();
 			break;
 
-			/* ST: *(u8*)(dst_reg + off) = imm */
 		case BPF_ST | BPF_MEM | BPF_B:
-			if (is_ereg(dst_reg))
-				EMIT2(0x41, 0xC6);
-			else
-				EMIT1(0xC6);
-			goto st;
 		case BPF_ST | BPF_MEM | BPF_H:
-			if (is_ereg(dst_reg))
-				EMIT3(0x66, 0x41, 0xC7);
-			else
-				EMIT2(0x66, 0xC7);
-			goto st;
 		case BPF_ST | BPF_MEM | BPF_W:
-			if (is_ereg(dst_reg))
-				EMIT2(0x41, 0xC7);
-			else
-				EMIT1(0xC7);
-			goto st;
 		case BPF_ST | BPF_MEM | BPF_DW:
-			if (dst_reg == BPF_REG_PARAMS && insn->off == -8) {
-				/* Arg 6: store immediate in r9 register */
-				emit_mov_imm64(&prog, X86_REG_R9, imm32 >> 31, (u32)imm32);
-				break;
-			}
-			EMIT2(add_1mod(0x48, dst_reg), 0xC7);
-
-st:			insn_off = insn->off;
-			if (dst_reg == BPF_REG_PARAMS) {
-				/*
-				 * Args 7+: reverse BPF negative offsets to
-				 * x86 positive rsp offsets.
-				 * BPF off=-16 → [rsp+0], off=-24 → [rsp+8], ...
-				 */
-				insn_off = outgoing_arg_base - outgoing_rsp - insn_off - 16;
-				dst_reg = BPF_REG_FP;
-			}
-			if (is_imm8(insn_off))
-				EMIT2(add_1reg(0x40, dst_reg), insn_off);
-			else
-				EMIT1_off32(add_1reg(0x80, dst_reg), insn_off);
-
-			EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
+			emit_st(&prog, insn, dst_reg, outgoing_arg_base,
+				outgoing_rsp);
 			break;
 
 			/* STX: *(u8*)(dst_reg + off) = src_reg */

-- 
2.55.0

Insert KASAN shadow memory checks before memory load and store
operations in JIT-compiled BPF programs. This helps detect memory safety
bugs such as use-after-free and out-of-bounds accesses at runtime.

The main instructions being targeted are BPF_ST, BPF_STX and BPF_LDX,
but not all of them are being instrumented:
- if the load/store instruction is in fact accessing the program stack,
  emit_kasan_check silently skips the instrumentation, as we can already
  benefit from guard pages to monitor stack accesses.
- if the load/store instruction is a BPF_PROBE_MEM or a BPF_PROBE_ATOMIC
  instruction, we do not instrument it, as the passed address can fault
  (hence the custom fault management with BPF_PROBE_XXX instructions),
  and so the corresponding kasan check could fault as well.

To support those new instructions insertion, create the
emit_kasan_check() helper that emits KASAN shadow memory checks before
memory accesses in JIT-compiled BPF programs. The implementation relies
on the existing __asan_{load,store}X functions from KASAN subsystem. The
helper:
- saves registers. This includes caller-saved registers, but also
  temporary registers, as those were possibly used by the
  affected program. Theoretically, r10 and r11 should be saved as well,
  but the number of called function and their scope being limited, they
  are skipped for the sake of reducing the overhead
- computes the accessed address and stores it in %rdi
- calls the relevant function, depending on the instruction being a load
  or a store, and the size of the access.
- restores registers

The special care needed when inserting this instrumentation comes at the
cost of a non negligeable increase in JITed code size. For example, a
bare

  mov 	0x0(%si),rbx # Load in rbx content at address stored in rsi

becomes

  push    %rax
  push    %rcx
  push    %rdx
  push    %rsi
  push    %rdi
  push    %r8
  push    %r9
  mov     %rsi,%rdi
  call    0xffffffff81da0a60 <__asan_load8>
  pop     %r9
  pop     %r8
  pop     %rdi
  pop     %rsi
  pop     %rdx
  pop     %rcx
  pop     %rax
  mov     0x0(%rsi),rbx

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v6:
- add a comment about r10/r11 being skipped in emit_kasan_check
- merge the commit defining the helper into the commit actually using
  it
- move non_stack_access check out of the emit_kasan_check helper
- replace hardcoded ip increment with actual computation

Changes in v5:
- (from former split commit) change access type (read -> write) for
  atomic RMW check

Changes in v4:
- (from former split commit) refactor BPF_FETCH handling

Changes in v3:
- skip kasan instrumentation if there is no verifier env (cBPF)
- move helper up in the file
- (from former split commit) fix LLVM23 build failure

Changes in v2:
- move asan functions declaration directly into jit compiler, and guard
  them with IS_ENABLED
- remove faulty stack alignment, no arg is passed to kasan funcs on the
  stack anyway
- make sure to emit call depth accounting code
- do not save unneeded registers
- update helper signature to let caller configure some values (eg:
  is_write)
- (from former split commit) support BPF_ATOMICS
- (from former split commit) support BPF_ST
- (from former split commit) make sure to systematically pass correct
  instruction to kasan check
---
 arch/x86/net/bpf_jit_comp.c | 188 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 171 insertions(+), 17 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 13ba3232993a..8134d028a2f2 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -21,6 +21,17 @@
 #include <asm/unwind.h>
 #include <asm/cfi.h>
 
+#if IS_ENABLED(CONFIG_BPF_JIT_KASAN)
+void __asan_load1(void *p);
+void __asan_store1(void *p);
+void __asan_load2(void *p);
+void __asan_store2(void *p);
+void __asan_load4(void *p);
+void __asan_store4(void *p);
+void __asan_load8(void *p);
+void __asan_store8(void *p);
+#endif
+
 static bool all_callee_regs_used[4] = {true, true, true, true};
 
 static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
@@ -1110,6 +1121,92 @@ static void maybe_emit_1mod(u8 **pprog, u32 reg, bool is64)
 	*pprog = prog;
 }
 
+static int emit_kasan_check(struct bpf_verifier_env *env, u8 **pprog,
+			    u32 addr_reg, struct bpf_insn *insn, u8 *ip,
+			    bool is_write)
+{
+#ifdef CONFIG_BPF_JIT_KASAN
+	u32 bpf_size = BPF_SIZE(insn->code);
+	s32 off = insn->off;
+	u8 *prog = *pprog;
+	void *kasan_func;
+
+	if (!env)
+		return 0;
+
+	/* Derive KASAN check function from access type and size */
+	switch (bpf_size) {
+	case BPF_B:
+		kasan_func = is_write ? __asan_store1 : __asan_load1;
+		break;
+	case BPF_H:
+		kasan_func = is_write ? __asan_store2 : __asan_load2;
+		break;
+	case BPF_W:
+		kasan_func = is_write ? __asan_store4 : __asan_load4;
+		break;
+	case BPF_DW:
+		kasan_func = is_write ? __asan_store8 : __asan_load8;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* Save rax */
+	EMIT1(0x50);
+	/* Save rcx */
+	EMIT1(0x51);
+	/* Save rdx */
+	EMIT1(0x52);
+	/* Save rsi */
+	EMIT1(0x56);
+	/* Save rdi */
+	EMIT1(0x57);
+	/* Save r8 */
+	EMIT2(0x41, 0x50);
+	/* Save r9 */
+	EMIT2(0x41, 0x51);
+	/*
+	 * SystemV ABI states that we should also save r10/r11, but in
+	 * practice those registers are _not_ used by the limited set of
+	 * kasan helpers we are calling here, so that's fine not to save those.
+	 */
+
+	/* mov rdi, addr_reg */
+	EMIT_mov(BPF_REG_1, addr_reg);
+
+	/* add rdi, off (if offset is non-zero) */
+	if (off) {
+		if (is_imm8(off)) {
+			/* add rdi, imm8 */
+			EMIT4(0x48, 0x83, 0xC7, (u8)off);
+		} else {
+			/* add rdi, imm32 */
+			EMIT3_off32(0x48, 0x81, 0xC7, off);
+		}
+	}
+
+	/* Adjust ip to account for the instrumentation generated so far */
+	ip += (prog - *pprog);
+	/* We emit a call, so update call depth counting */
+	ip += x86_call_depth_emit_accounting(&prog, kasan_func, ip);
+	/* call kasan_func */
+	if (emit_call(&prog, kasan_func, ip))
+		return -ERANGE;
+
+	EMIT2(0x41, 0x59);
+	EMIT2(0x41, 0x58);
+	EMIT1(0x5F);
+	EMIT1(0x5E);
+	EMIT1(0x5A);
+	EMIT1(0x59);
+	EMIT1(0x58);
+
+	*pprog = prog;
+#endif /* CONFIG_BPF_JIT_KASAN */
+	return 0;
+}
+
 /* LDX: dst_reg = *(u8*)(src_reg + off) */
 static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
 {
@@ -1480,17 +1577,35 @@ static int emit_atomic_rmw_index(u8 **pprog, u32 atomic_op, u32 size,
 	return 0;
 }
 
-static int emit_atomic_ld_st(u8 **pprog, u32 atomic_op, u32 dst_reg,
-			     u32 src_reg, s16 off, u8 bpf_size)
+static int emit_atomic_ld_st(struct bpf_verifier_env *env, u8 **pprog,
+			     struct bpf_insn *insn, u8 *ip, u32 dst_reg,
+			     u32 src_reg, bool accesses_stack_only)
 {
+	u32 atomic_op = insn->imm;
+	int err;
+
 	switch (atomic_op) {
 	case BPF_LOAD_ACQ:
+		if (!accesses_stack_only) {
+			err = emit_kasan_check(env, pprog, src_reg, insn, ip,
+					       false);
+			if (err)
+				return err;
+		}
 		/* dst_reg = smp_load_acquire(src_reg + off16) */
-		emit_ldx(pprog, bpf_size, dst_reg, src_reg, off);
+		emit_ldx(pprog, BPF_SIZE(insn->code), dst_reg, src_reg,
+			 insn->off);
 		break;
 	case BPF_STORE_REL:
+		if (!accesses_stack_only) {
+			err = emit_kasan_check(env, pprog, dst_reg, insn, ip,
+					       true);
+			if (err)
+				return err;
+		}
 		/* smp_store_release(dst_reg + off16, src_reg) */
-		emit_stx(pprog, bpf_size, dst_reg, src_reg, off);
+		emit_stx(pprog, BPF_SIZE(insn->code), dst_reg, src_reg,
+			 insn->off);
 		break;
 	default:
 		pr_err("bpf_jit: unknown atomic load/store opcode %02x\n",
@@ -1911,10 +2026,12 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 		const s32 imm32 = insn->imm;
 		u32 dst_reg = insn->dst_reg;
 		u32 src_reg = insn->src_reg;
+		bool accesses_stack_only;
 		u8 b2 = 0, b3 = 0;
 		u8 *start_of_ldx;
 		s64 jmp_offset;
 		s32 insn_off;
+		int insn_idx;
 		u8 jmp_cond;
 		u8 *func;
 		int nops;
@@ -1931,6 +2048,10 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 			EMIT_ENDBR();
 
 		ip = image + addrs[i - 1] + (prog - temp);
+		insn_idx = i - 1 + bpf_prog->aux->subprog_start;
+		accesses_stack_only =
+			env ? !env->insn_aux_data[insn_idx].non_stack_access :
+			      false;
 
 		switch (insn->code) {
 			/* ALU */
@@ -2311,6 +2432,13 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 		case BPF_ST | BPF_MEM | BPF_H:
 		case BPF_ST | BPF_MEM | BPF_W:
 		case BPF_ST | BPF_MEM | BPF_DW:
+			if (!accesses_stack_only) {
+				err = emit_kasan_check(env, &prog, dst_reg,
+						       insn, ip, true);
+				if (err)
+					return err;
+			}
+
 			emit_st(&prog, insn, dst_reg, outgoing_arg_base,
 				outgoing_rsp);
 			break;
@@ -2330,6 +2458,12 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 				insn_off = outgoing_arg_base - outgoing_rsp - insn_off - 16;
 				dst_reg = BPF_REG_FP;
 			}
+			if (!accesses_stack_only) {
+				err = emit_kasan_check(env, &prog, dst_reg,
+						       insn, ip, true);
+				if (err)
+					return err;
+			}
 			emit_stx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn_off);
 			break;
 
@@ -2511,6 +2645,11 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 				/* populate jmp_offset for JAE above to jump to start_of_ldx */
 				start_of_ldx = prog;
 				end_of_jmp[-1] = start_of_ldx - end_of_jmp;
+			} else if (!accesses_stack_only) {
+				err = emit_kasan_check(env, &prog, src_reg,
+						       insn, ip, false);
+				if (err)
+					return err;
 			}
 			if (BPF_MODE(insn->code) == BPF_PROBE_MEMSX ||
 			    BPF_MODE(insn->code) == BPF_MEMSX)
@@ -2572,28 +2711,42 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 			}
 			fallthrough;
 		case BPF_STX | BPF_ATOMIC | BPF_W:
-		case BPF_STX | BPF_ATOMIC | BPF_DW:
-			if (insn->imm == (BPF_AND | BPF_FETCH) ||
-			    insn->imm == (BPF_OR | BPF_FETCH) ||
-			    insn->imm == (BPF_XOR | BPF_FETCH)) {
-				bool is64 = BPF_SIZE(insn->code) == BPF_DW;
-				u32 real_src_reg = src_reg;
-				u32 real_dst_reg = dst_reg;
-				u8 *branch_target;
-
+		case BPF_STX | BPF_ATOMIC | BPF_DW: {
+			bool is64 = BPF_SIZE(insn->code) == BPF_DW;
+			u32 real_src_reg = src_reg;
+			u32 real_dst_reg = dst_reg;
+			u8 *branch_target;
+			u8 *pprog;
+			bool is_atomic_fetch =
+				(insn->imm == (BPF_AND | BPF_FETCH) ||
+				 insn->imm == (BPF_OR | BPF_FETCH) ||
+				 insn->imm == (BPF_XOR | BPF_FETCH));
+			if (is_atomic_fetch) {
 				/*
 				 * Can't be implemented with a single x86 insn.
 				 * Need to do a CMPXCHG loop.
 				 */
 
 				/* Will need RAX as a CMPXCHG operand so save R0 */
+				pprog = prog;
 				emit_mov_reg(&prog, true, BPF_REG_AX, BPF_REG_0);
 				if (src_reg == BPF_REG_0)
 					real_src_reg = BPF_REG_AX;
 				if (dst_reg == BPF_REG_0)
 					real_dst_reg = BPF_REG_AX;
-
+				ip += (prog - pprog);
+			}
+			if (!bpf_atomic_is_load_store(insn)) {
+				if (!accesses_stack_only) {
+					err = emit_kasan_check(env, &prog,
+							       real_dst_reg,
+							       insn, ip, true);
+					if (err)
+						return err;
+				}
 				branch_target = prog;
+			}
+			if (is_atomic_fetch) {
 				/* Load old value */
 				emit_ldx(&prog, BPF_SIZE(insn->code),
 					 BPF_REG_0, real_dst_reg, insn->off);
@@ -2625,15 +2778,16 @@ static int do_jit(struct bpf_verifier_env *env, struct bpf_prog *bpf_prog, int *
 			}
 
 			if (bpf_atomic_is_load_store(insn))
-				err = emit_atomic_ld_st(&prog, insn->imm, dst_reg, src_reg,
-							insn->off, BPF_SIZE(insn->code));
+				err = emit_atomic_ld_st(env, &prog, insn, ip,
+							dst_reg, src_reg,
+							accesses_stack_only);
 			else
 				err = emit_atomic_rmw(&prog, insn->imm, dst_reg, src_reg,
 						      insn->off, BPF_SIZE(insn->code));
 			if (err)
 				return err;
 			break;
-
+		}
 		case BPF_STX | BPF_PROBE_ATOMIC | BPF_B:
 		case BPF_STX | BPF_PROBE_ATOMIC | BPF_H:
 			if (!bpf_atomic_is_load_store(insn)) {

-- 
2.55.0

Mark x86 as supporting KASAN checks in JITed programs so that the
corresponding JIT compiler inserts checks on the translated
instructions.

Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 arch/x86/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 48ccc3e6059d..745890d91e99 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -234,6 +234,7 @@ config X86
 	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
 	select HAVE_EBPF_JIT
+	select HAVE_EBPF_JIT_KASAN		if X86_64
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_EISA			if X86_32
 	select HAVE_EXIT_THREAD

-- 
2.55.0

cmdline_contains is used by BPF selftests to check the presence of
specific kernel commandline parameters, but it currently suffers from
two issues:
- the read commandline isn't NULL terminated right after the read data
  but only at the end of the buffer, leaving uninitialized bytes that
  are then possibly tokenized
- the comparison of found tokens is done based on the size of found
  token. This could lead to too-short-but-matching tokens to wrongly
  match the search pattern.

Enforce stricter checks in cmdline_contains to avoid accidental matches.

Fixes: 399f6185a1c0 ("selftests/bpf: Fix selftests broken by mitigations=off")
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v7:
- add missing Fixes tag
- drop unneeded size check, already done by strcmp
---
 tools/testing/selftests/bpf/unpriv_helpers.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/bpf/unpriv_helpers.c b/tools/testing/selftests/bpf/unpriv_helpers.c
index f997d7ec8fd0..9dadcacaef0c 100644
--- a/tools/testing/selftests/bpf/unpriv_helpers.c
+++ b/tools/testing/selftests/bpf/unpriv_helpers.c
@@ -72,8 +72,8 @@ static int config_contains(const char *pat)
 
 static bool cmdline_contains(const char *pat)
 {
+	int fd, cnt, ret = false;
 	char cmdline[4096], *c;
-	int fd, ret = false;
 
 	fd = open("/proc/cmdline", O_RDONLY);
 	if (fd < 0) {
@@ -81,14 +81,15 @@ static bool cmdline_contains(const char *pat)
 		return false;
 	}
 
-	if (read(fd, cmdline, sizeof(cmdline) - 1) < 0) {
+	cnt = read(fd, cmdline, sizeof(cmdline) - 1);
+	if (cnt < 0) {
 		perror("read /proc/cmdline");
 		goto out;
 	}
 
-	cmdline[sizeof(cmdline) - 1] = '\0';
+	cmdline[cnt] = '\0';
 	for (c = strtok(cmdline, " \n"); c; c = strtok(NULL, " \n")) {
-		if (strncmp(c, pat, strlen(c)))
+		if (strcmp(c, pat))
 			continue;
 		ret = true;
 		break;

-- 
2.55.0

Add two simple helpers to allow checking whether KASAN for eBPF tests
should be executed:
- one helper to check if BPF_JIT_KASAN is enabled in kernel
  configuration
- one helper to check if the kernel is running with kasan_multi_shot
  (otherwise only the first test will be able to trigger a report)

Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v5:
- add kasan_multi_shot helper

Changes in v2:
- fix condition
---
 tools/testing/selftests/bpf/unpriv_helpers.c | 10 ++++++++++
 tools/testing/selftests/bpf/unpriv_helpers.h |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/tools/testing/selftests/bpf/unpriv_helpers.c b/tools/testing/selftests/bpf/unpriv_helpers.c
index 9dadcacaef0c..2c8c5edb8751 100644
--- a/tools/testing/selftests/bpf/unpriv_helpers.c
+++ b/tools/testing/selftests/bpf/unpriv_helpers.c
@@ -143,3 +143,13 @@ bool get_unpriv_disabled(void)
 	}
 	return mitigations_off;
 }
+
+bool get_kasan_jit_enabled(void)
+{
+	return config_contains("CONFIG_BPF_JIT_KASAN=y") == 1;
+}
+
+bool get_kasan_multi_shot_enabled(void)
+{
+	return cmdline_contains("kasan_multi_shot");
+}
diff --git a/tools/testing/selftests/bpf/unpriv_helpers.h b/tools/testing/selftests/bpf/unpriv_helpers.h
index 151f67329665..a7ceb51577cd 100644
--- a/tools/testing/selftests/bpf/unpriv_helpers.h
+++ b/tools/testing/selftests/bpf/unpriv_helpers.h
@@ -5,3 +5,5 @@
 #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
 
 bool get_unpriv_disabled(void);
+bool get_kasan_jit_enabled(void);
+bool get_kasan_multi_shot_enabled(void);

-- 
2.55.0

Move set_bpf_jit_harden to testing helpers so that other selftests can
change the hardening configuration without re-implementing a helper.

Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v5:
- check set_bpf_jit_harden return code in cleanup path

Changes in v3:
- new patch
---
 .../selftests/bpf/prog_tests/bpf_insn_array.c      | 44 +++-------------------
 tools/testing/selftests/bpf/testing_helpers.c      | 32 ++++++++++++++++
 tools/testing/selftests/bpf/testing_helpers.h      |  1 +
 3 files changed, 38 insertions(+), 39 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
index 0222a9a5d076..815f3e04540f 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c
@@ -227,42 +227,6 @@ static void check_incorrect_index(void)
 	check_mid_insn_index();
 }
 
-static int set_bpf_jit_harden(char *level)
-{
-	char old_level;
-	int err = -1;
-	int fd = -1;
-
-	fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK);
-	if (fd < 0) {
-		ASSERT_FAIL("open .../bpf_jit_harden returned %d (errno=%d)", fd, errno);
-		return -1;
-	}
-
-	err = read(fd, &old_level, 1);
-	if (err != 1) {
-		ASSERT_FAIL("read from .../bpf_jit_harden returned %d (errno=%d)", err, errno);
-		err = -1;
-		goto end;
-	}
-
-	lseek(fd, 0, SEEK_SET);
-
-	err = write(fd, level, 1);
-	if (err != 1) {
-		ASSERT_FAIL("write to .../bpf_jit_harden returned %d (errno=%d)", err, errno);
-		err = -1;
-		goto end;
-	}
-
-	err = 0;
-	*level = old_level;
-end:
-	if (fd >= 0)
-		close(fd);
-	return err;
-}
-
 static void check_blindness(void)
 {
 	struct bpf_insn insns[] = {
@@ -272,7 +236,7 @@ static void check_blindness(void)
 		BPF_MOV64_IMM(BPF_REG_0, 1),
 		BPF_EXIT_INSN(),
 	};
-	int prog_fd = -1, map_fd;
+	int prog_fd = -1, map_fd, ret;
 	struct bpf_insn_array_value val = {};
 	char bpf_jit_harden = '@'; /* non-exizsting value */
 	int i;
@@ -291,7 +255,8 @@ static void check_blindness(void)
 		goto cleanup;
 
 	bpf_jit_harden = '2';
-	if (set_bpf_jit_harden(&bpf_jit_harden)) {
+	ret = set_bpf_jit_harden(&bpf_jit_harden);
+	if (!ASSERT_OK(ret, "set bpf_jit_harden")) {
 		bpf_jit_harden = '@'; /* open, read or write failed => no write was done */
 		goto cleanup;
 	}
@@ -313,7 +278,8 @@ static void check_blindness(void)
 cleanup:
 	/* restore the old one */
 	if (bpf_jit_harden != '@')
-		set_bpf_jit_harden(&bpf_jit_harden);
+		ASSERT_OK(set_bpf_jit_harden(&bpf_jit_harden),
+			  "restore hardening configuration");
 
 	close(prog_fd);
 	close(map_fd);
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index c970e7793dfc..737f668b35e2 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -519,6 +519,38 @@ bool is_jit_enabled(void)
 	return enabled;
 }
 
+int set_bpf_jit_harden(char *level)
+{
+	char old_level;
+	int err = -1;
+	int fd = -1;
+
+	fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK);
+	if (fd < 0)
+		return -1;
+
+	err = read(fd, &old_level, 1);
+	if (err != 1) {
+		err = -1;
+		goto end;
+	}
+
+	lseek(fd, 0, SEEK_SET);
+
+	err = write(fd, level, 1);
+	if (err != 1) {
+		err = -1;
+		goto end;
+	}
+
+	err = 0;
+	*level = old_level;
+end:
+	if (fd >= 0)
+		close(fd);
+	return err;
+}
+
 int stack_mprotect(void)
 {
 	void *buf;
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 2edc6fb7fc52..e00642afe86f 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -59,6 +59,7 @@ struct bpf_insn;
 int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt);
 int testing_prog_flags(void);
 bool is_jit_enabled(void);
+int set_bpf_jit_harden(char *level);
 int stack_mprotect(void);
 
 #endif /* __TESTING_HELPERS_H */

-- 
2.55.0

Add a basic KASAN test runner that loads and test-run programs that can
trigger memory management bugs. The test captures kernel logs and ensure
that the expected KASAN splat is emitted by searching for the
corresponding first lines in the report, hence validated that the needed
instrumentation has been inserted by the JIT compiler before the
relevant memory accesses. To allow each test to trigger the expected
report, the kernel must run with the kasan_multi_shot configuration.

The runner covers different cases and settings: in the nominal case, it
validates kasan reports on basic instructions (on all supported accesses
sizes) but also when report _should not_ be emitted (eg: for accesses on
program stack). The runner also comes with a few specialized tests that
are then not executed for all sizes/locations:
- specific atomic ops
- test for instructions involving different verifier states, with some
  states flagging memory as stack, and other states as non-stack memory
- tests that validate the stack marking shifting when a patch is emitted
  by the verifier (zext/rnd_hi32, constant blindind).
Most of those tests are able to trigger kasan reports by altering the
shadow memory (triggering faulty accesses is otherwise complex, because
of the verifier). A few tests trigger actual faulty accesses (eg
out-of-bound accesses)

A few of those tests depends on cpuv4 (load_acquire and store_release).

  # ./test_progs -a kasan
  #171/1   kasan/st_1_not_on_stack:OK
  #171/2   kasan/st_1_on_stack:OK
  #171/3   kasan/st_2_not_on_stack:OK
  #171/4   kasan/st_2_on_stack:OK
  #171/5   kasan/st_4_not_on_stack:OK
  #171/6   kasan/st_4_on_stack:OK
  #171/7   kasan/st_8_not_on_stack:OK
  #171/8   kasan/st_8_on_stack:OK
  #171/9   kasan/stx_1_not_on_stack:OK
  #171/10  kasan/stx_1_on_stack:OK
  #171/11  kasan/stx_2_not_on_stack:OK
  #171/12  kasan/stx_2_on_stack:OK
  #171/13  kasan/stx_4_not_on_stack:OK
  #171/14  kasan/stx_4_on_stack:OK
  #171/15  kasan/stx_8_not_on_stack:OK
  #171/16  kasan/stx_8_on_stack:OK
  #171/17  kasan/ldx_1_not_on_stack:OK
  #171/18  kasan/ldx_1_on_stack:OK
  #171/19  kasan/ldx_2_not_on_stack:OK
  #171/20  kasan/ldx_2_on_stack:OK
  #171/21  kasan/ldx_4_not_on_stack:OK
  #171/22  kasan/ldx_4_on_stack:OK
  #171/23  kasan/ldx_8_not_on_stack:OK
  #171/24  kasan/ldx_8_on_stack:OK
  #171/25  kasan/simple_atomic_4_not_on_stack:OK
  #171/26  kasan/simple_atomic_4_on_stack:OK
  #171/27  kasan/simple_atomic_8_not_on_stack:OK
  #171/28  kasan/simple_atomic_8_on_stack:OK
  #171/29  kasan/simple_atomic_fetch:OK
  #171/30  kasan/simple_atomic_fetch:OK
  #171/31  kasan/load_acquire_1_not_on_stack:SKIP
  #171/32  kasan/load_acquire_1_on_stack:SKIP
  #171/33  kasan/load_acquire_2_not_on_stack:SKIP
  #171/34  kasan/load_acquire_2_on_stack:SKIP
  #171/35  kasan/load_acquire_4_not_on_stack:SKIP
  #171/36  kasan/load_acquire_4_on_stack:SKIP
  #171/37  kasan/load_acquire_8_not_on_stack:SKIP
  #171/38  kasan/load_acquire_8_on_stack:SKIP
  #171/39  kasan/store_release_1_not_on_stack:SKIP
  #171/40  kasan/store_release_1_on_stack:SKIP
  #171/41  kasan/store_release_2_not_on_stack:SKIP
  #171/42  kasan/store_release_2_on_stack:SKIP
  #171/43  kasan/store_release_4_not_on_stack:SKIP
  #171/44  kasan/store_release_4_on_stack:SKIP
  #171/45  kasan/store_release_8_not_on_stack:SKIP
  #171/46  kasan/store_release_8_on_stack:SKIP
  #171/47  kasan/ldx_patched:OK
  #171/48  kasan/ldx_patched:OK
  #171/49  kasan/verifier_paths_stack_and_non_stack:OK
  #171/50  kasan/ldx_oob_1_not_on_stack:OK
  #171/51  kasan/ldx_oob_2_not_on_stack:OK
  #171/52  kasan/ldx_oob_4_not_on_stack:OK
  #171/53  kasan/ldx_oob_8_not_on_stack:OK
  #171/54  kasan/st_blinded:OK
  #171     kasan:OK (SKIP: 16/54)
  Summary: 1/38 PASSED, 16 SKIPPED, 0 FAILED

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v6:
- rename test struct in kasan program
- add oob testing
- add atomic fetch tests
- refactor a bit the test runner so that ldx_patched tests are not
  treated as special cases
- break kernel log reading loop immediately if no bytes are read

Changes in v5:
- check snprintf return codes when checking kernel logs
- skip tests in kasan_multi_shot is not enabled
- update simple atomic test expected access type (read -> write)

Changes in v4:
- prevent interleaved kernel logs from breaking kasan report search
- make new kfuncs in bpf_testmod depend on BPF_JIT_KASAN rather than
  KASAN_GENERIC
- initialize buffer passed to bpf_prog_test_run_opts

Changes in v3:
- increase kernel log buffer size
- fix comment style
- check bpf_program__fd return code
- document kasan_multi_shot
- fix copy-paste mistakes on poisoning/unpoisoning sequences
- add test for patch due to constant blinding

Changes in v2:
- simplify tests by just manually poisoning test areas with a dedicated
  kfunc
- introduce one prog per covered instruction family
- make sure that tests do not consume kernel logs (use /dev/kmgs rather
  than klogctl)
- add tests for stack accesses:
  - marking correctly set when there are diverging verifier states
    leading to different memory types
  - marking kept in sync with prog when it is patched
---
 tools/testing/selftests/bpf/prog_tests/kasan.c     | 454 ++++++++++++++++++++
 tools/testing/selftests/bpf/progs/kasan.c          | 462 +++++++++++++++++++++
 tools/testing/selftests/bpf/progs/kasan_harden.c   |  41 ++
 .../testing/selftests/bpf/test_kmods/bpf_testmod.c |  55 +++
 4 files changed, 1012 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/kasan.c b/tools/testing/selftests/bpf/prog_tests/kasan.c
new file mode 100644
index 000000000000..2b424767a0f3
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kasan.c
@@ -0,0 +1,454 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+/*
+ * Tests validating that KASAN reports are properly instrumented and
+ * generated on a wide variety of instructions. The running kernel needs
+ * kasan_multi_shot to run multiple kasan-generating subtests at once
+ */
+#include <bpf/bpf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/if_ether.h>
+#include <unistd.h>
+#include <test_progs.h>
+#include <unpriv_helpers.h>
+#include "kasan.skel.h"
+#include "kasan_harden.skel.h"
+
+#define SUBTEST_NAME_MAX_LEN	128
+#define PROG_NAME_MAX_LEN	128
+
+#define MAX_LOG_SIZE		(8 * 1024)
+#define READ_CHUNK_SIZE		256
+
+#define KASAN_PATTERN_SLAB_UAF "BUG: KASAN: slab-use-after-free " \
+	"in bpf_prog_%02x%02x%02x%02x%02x%02x%02x%02x_%s"
+#define KASAN_PATTERN_SLAB_OOB "BUG: KASAN: slab-out-of-bounds " \
+	"in bpf_prog_%02x%02x%02x%02x%02x%02x%02x%02x_%s"
+#define KASAN_PATTERN_REPORT "%s of size %d at addr"
+
+static char klog_buffer[MAX_LOG_SIZE];
+static char record[MAX_LOG_SIZE];
+
+struct test_spec {
+	char *prog_type;
+	bool is_write;
+	bool only_32_or_64;
+	bool needs_load_acq_store_rel;
+	bool skip_multi_size_testing;
+	bool skip_on_stack_testing;
+	int run_size;
+	bool expect_no_report;
+	bool rnd_hi32;
+	bool is_oob;
+};
+
+struct kasan_write_val {
+	__u8 data_1;
+	__u16 data_2;
+	__u32 data_4;
+	__u64 data_8;
+};
+
+struct test_ctx {
+	__u8  prog_tag[BPF_TAG_SIZE];
+	struct bpf_object *obj;
+	int *access_size;
+	bool skip_load_acq_store_rel;
+	struct bpf_program *prog;
+	char prog_name[SUBTEST_NAME_MAX_LEN];
+	int klog_fd;
+};
+
+static int open_kernel_logs(void)
+{
+	int fd;
+
+	fd = open("/dev/kmsg", O_RDONLY | O_NONBLOCK);
+
+	return fd;
+}
+
+static void skip_kernel_logs(int fd)
+{
+	lseek(fd, 0, SEEK_END);
+}
+
+static int read_kernel_logs(int fd, char *buf, size_t max_len)
+{
+	size_t total = 0;
+	ssize_t n;
+
+	buf[0] = '\0';
+	while (1) {
+		char *msg, *eol;
+		size_t len;
+
+		n = read(fd, record, sizeof(record) - 1);
+		if (n == 0)
+			break;
+
+		if (n < 0) {
+			if (errno == EAGAIN)
+				break;
+			return n;
+		}
+		record[n] = '\0';
+
+		/*
+		 * Each kmsg record starts with some metadata, separated
+		 * from the actual content by a semi-colon
+		 */
+		msg = strchr(record, ';');
+		if (!msg)
+			continue;
+		msg++;
+		eol = strchr(msg, '\n');
+		if (eol)
+			*eol = '\0';
+
+		len = strlen(msg);
+		if (total + len + 2 > max_len)
+			break;
+		memcpy(buf + total, msg, len);
+		total += len;
+		buf[total++] = '\n';
+		buf[total] = '\0';
+	}
+
+	return total;
+}
+
+static int check_kasan_report_in_kernel_logs(char *buf, struct test_ctx *ctx,
+					     bool is_write, int size,
+					     bool is_oob)
+{
+	char access_log[READ_CHUNK_SIZE];
+	const char *pattern;
+	char *kasan_report_start;
+	int nsize;
+
+	pattern = is_oob ? KASAN_PATTERN_SLAB_OOB : KASAN_PATTERN_SLAB_UAF;
+	nsize = snprintf(access_log, READ_CHUNK_SIZE, pattern,
+			 ctx->prog_tag[0], ctx->prog_tag[1], ctx->prog_tag[2],
+			 ctx->prog_tag[3], ctx->prog_tag[4], ctx->prog_tag[5],
+			 ctx->prog_tag[6], ctx->prog_tag[7], ctx->prog_name);
+	if (!ASSERT_GE(nsize, 0, "format kasan access header line"))
+		return nsize;
+	/*
+	 * Searched kasan report is valid if
+	 * - it contains the expected kasan pattern
+	 * - the description of the faulty access is found somewhere
+	 *   after the header (not necessarily on the very next line,
+	 *   because other kernel messages may interleave)
+	 * - faulty access properties match the tested type and size
+	 */
+	kasan_report_start = strstr(buf, access_log);
+
+	if (!kasan_report_start)
+		return 1;
+
+	nsize = snprintf(access_log, READ_CHUNK_SIZE, KASAN_PATTERN_REPORT,
+			 is_write ? "Write" : "Read", size);
+	if (!ASSERT_GE(nsize, 0, "format kasan access report line"))
+		return nsize;
+
+	if (!strstr(kasan_report_start, access_log))
+		return 1;
+
+	return 0;
+}
+
+static void exec_subtest(struct test_ctx *ctx, struct test_spec *test,
+			 int access_size, bool on_stack)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	struct bpf_prog_info info;
+	uint8_t buf[ETH_HLEN] = {0};
+	int ret, prog_fd;
+	__u32 info_len;
+
+	ctx->prog = bpf_object__find_program_by_name(ctx->obj,
+						     ctx->prog_name);
+	if (!ASSERT_OK_PTR(ctx->prog, "find test prog"))
+		return;
+
+	info_len = sizeof(info);
+	memset(&info, 0, info_len);
+	prog_fd = bpf_program__fd(ctx->prog);
+	if (!ASSERT_OK_FD(prog_fd, "get prog fd"))
+		return;
+	ret = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
+	if (!ASSERT_OK(ret, "fetch loaded program info"))
+		return;
+	memcpy(ctx->prog_tag, info.tag, BPF_TAG_SIZE);
+
+	skip_kernel_logs(ctx->klog_fd);
+
+	topts.sz = sizeof(struct bpf_test_run_opts);
+	topts.data_size_in = ETH_HLEN;
+	topts.data_in = buf;
+	if (ctx->access_size)
+		*ctx->access_size = access_size;
+	ret = bpf_prog_test_run_opts(bpf_program__fd(ctx->prog),
+				     &topts);
+	if (!ASSERT_OK(ret, "run prog"))
+		return;
+
+	ret = read_kernel_logs(ctx->klog_fd, klog_buffer, MAX_LOG_SIZE);
+	if (!ASSERT_GE(ret, 0, "read kernel logs"))
+		return;
+
+	ret = check_kasan_report_in_kernel_logs(klog_buffer, ctx,
+						test->is_write, access_size,
+						test->is_oob);
+	if (on_stack || test->expect_no_report)
+		ASSERT_NEQ(ret, 0, "no report should be generated");
+	else
+		ASSERT_OK(ret, "report should be generated");
+}
+
+static void run_subtest_with_size_and_location(struct test_ctx *ctx,
+					       struct test_spec *test,
+					       int access_size,
+					       bool on_stack)
+{
+	char subtest_name[SUBTEST_NAME_MAX_LEN];
+
+	if (test->skip_multi_size_testing) {
+		snprintf(subtest_name, SUBTEST_NAME_MAX_LEN, "%s%s",
+			 test->prog_type,
+			 test->skip_on_stack_testing ? "" :
+			 on_stack		     ? "_on_stack" :
+						       "_not_on_stack");
+	} else {
+		snprintf(subtest_name, SUBTEST_NAME_MAX_LEN, "%s_%d_%s",
+			 test->prog_type, access_size,
+			 on_stack ? "on_stack" : "not_on_stack");
+	}
+
+	snprintf(ctx->prog_name, PROG_NAME_MAX_LEN, "%s%s", test->prog_type,
+		 test->skip_on_stack_testing ? "" :
+		 on_stack		     ? "_on_stack" :
+					       "_not_on_stack");
+
+	if (!test__start_subtest(subtest_name))
+		return;
+
+	if (test->needs_load_acq_store_rel && ctx->skip_load_acq_store_rel) {
+		test__skip();
+		return;
+	}
+
+	exec_subtest(ctx, test, access_size, on_stack);
+}
+
+static void run_subtest_with_size(struct test_ctx *ctx, struct test_spec *test,
+				  int size)
+{
+	run_subtest_with_size_and_location(ctx, test, size, false);
+	if (!test->skip_on_stack_testing)
+		run_subtest_with_size_and_location(ctx, test, size, true);
+}
+
+static void run_subtest(struct test_ctx *ctx, struct test_spec *test)
+{
+	if (test->skip_multi_size_testing) {
+		run_subtest_with_size(ctx, test, test->run_size);
+		return;
+	}
+
+	if (!test->only_32_or_64) {
+		run_subtest_with_size(ctx, test, 1);
+		run_subtest_with_size(ctx, test, 2);
+	}
+	run_subtest_with_size(ctx, test, 4);
+	run_subtest_with_size(ctx, test, 8);
+}
+
+static void run_blinding_subtest(void)
+{
+	struct test_spec blinding_spec = {
+		.prog_type = "st_blinded",
+		.is_write = true,
+	};
+	char bpf_jit_harden = '2';
+	struct kasan_harden *skel;
+	struct test_ctx *ctx;
+
+	if (!test__start_subtest("st_blinded"))
+		return;
+
+	ctx = calloc(1, sizeof(*ctx));
+	if (!ASSERT_OK_PTR(ctx, "alloc blinding ctx"))
+		return;
+	ctx->klog_fd = -1;
+
+	if (set_bpf_jit_harden(&bpf_jit_harden))
+		goto free_ctx;
+
+	skel = kasan_harden__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "open and load blinded prog"))
+		goto restore;
+
+	ctx->klog_fd = open_kernel_logs();
+	if (!ASSERT_OK_FD(ctx->klog_fd, "open kernel logs"))
+		goto destroy;
+
+	ctx->obj = skel->obj;
+	strncpy(ctx->prog_name, "st_blinded", PROG_NAME_MAX_LEN);
+
+	exec_subtest(ctx, &blinding_spec, 1, false);
+
+destroy:
+	close(ctx->klog_fd);
+	kasan_harden__destroy(skel);
+restore:
+	set_bpf_jit_harden(&bpf_jit_harden);
+free_ctx:
+	free(ctx);
+}
+
+static struct test_spec tests[] = {
+	{
+		.prog_type = "st",
+		.is_write = true
+	},
+	{
+		.prog_type = "stx",
+		.is_write = true
+	},
+	{
+		.prog_type = "ldx",
+		.is_write = false
+	},
+	{
+		.prog_type = "simple_atomic",
+		.is_write = true,
+		.only_32_or_64 = true
+	},
+	{
+		.prog_type = "simple_atomic_fetch",
+		.is_write = true,
+		.skip_multi_size_testing = true,
+		.run_size = 8,
+	},
+	{
+		.prog_type = "load_acquire",
+		.is_write = false,
+		.needs_load_acq_store_rel = true
+	},
+	{
+		.prog_type = "store_release",
+		.is_write = true,
+		.needs_load_acq_store_rel = true
+	},
+	{
+		.prog_type = "ldx_patched",
+		.is_write = false,
+		.skip_multi_size_testing = true,
+		.run_size = 4,
+		.rnd_hi32 = true
+	},
+	{
+		.prog_type = "verifier_paths_stack_and_non_stack",
+		.is_write = true,
+		.skip_multi_size_testing = true,
+		.skip_on_stack_testing = true,
+		.run_size = 1
+	},
+	{
+		.prog_type = "ldx_oob",
+		.is_write = false,
+		.skip_on_stack_testing = true,
+		.is_oob = true
+	},
+};
+
+void test_kasan(void)
+{
+	struct kasan_write_val val;
+	struct test_spec *test;
+	struct test_ctx *ctx;
+	struct kasan *skel;
+	__u32 key = 0;
+	int i, ret;
+
+	ctx = calloc(1, sizeof(struct test_ctx));
+	if (!ASSERT_OK_PTR(ctx, "alloc test ctx"))
+		return;
+
+	if (!is_jit_enabled() || !get_kasan_jit_enabled() ||
+	    !get_kasan_multi_shot_enabled()) {
+		test__skip();
+		goto end;
+	}
+
+	skel = kasan__open();
+	if (!ASSERT_OK_PTR(skel, "open prog"))
+		goto end;
+
+	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+		char prog_name[SUBTEST_NAME_MAX_LEN];
+		struct bpf_program *prog;
+
+		if (!tests[i].rnd_hi32)
+			continue;
+
+		snprintf(prog_name, SUBTEST_NAME_MAX_LEN, "%s_%s",
+			 tests[i].prog_type, "on_stack");
+		prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+		if (!ASSERT_OK_PTR(prog, "find rnd_hi32 on_stack prog"))
+			goto destroy;
+		bpf_program__set_flags(prog, BPF_F_TEST_RND_HI32);
+		snprintf(prog_name, SUBTEST_NAME_MAX_LEN, "%s_%s",
+			 tests[i].prog_type, "not_on_stack");
+		prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+		if (!ASSERT_OK_PTR(prog, "find rnd_hi32 not_on_stack prog"))
+			goto destroy;
+		bpf_program__set_flags(prog, BPF_F_TEST_RND_HI32);
+	}
+
+	if (!ASSERT_OK(kasan__load(skel), "load prog"))
+		goto destroy;
+
+	ctx->obj = skel->obj;
+	ctx->access_size = &skel->bss->access_size;
+	ctx->skip_load_acq_store_rel = skel->data->skip_load_acq_store_rel_tests;
+
+	ctx->klog_fd = open_kernel_logs();
+	if (!ASSERT_OK_FD(ctx->klog_fd, "open kernel logs"))
+		goto destroy;
+
+	/* Fill map with recognizable values */
+	ret = bpf_map__lookup_elem(skel->maps.test_map, &key, sizeof(key),
+				   &val, sizeof(val), 0);
+	if (!ASSERT_OK(ret, "get map"))
+		goto close;
+	val.data_1 = 0xAA;
+	val.data_2 = 0xBBBB;
+	val.data_4 = 0xCCCCCCCC;
+	val.data_8 = 0xDDDDDDDDDDDDDDDD;
+	ret = bpf_map__update_elem(skel->maps.test_map, &key, sizeof(key),
+				   &val, sizeof(val), 0);
+	if (!ASSERT_OK(ret, "set map"))
+		goto close;
+
+	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+		test = &tests[i];
+		run_subtest(ctx, test);
+	}
+
+	/*
+	 * Blinding subtest is handled differently as it needs the
+	 * corresponding program to be loaded with bpf_jit_harden raised
+	 */
+	run_blinding_subtest();
+
+close:
+	close(ctx->klog_fd);
+destroy:
+	kasan__destroy(skel);
+end:
+	free(ctx);
+}
diff --git a/tools/testing/selftests/bpf/progs/kasan.c b/tools/testing/selftests/bpf/progs/kasan.c
new file mode 100644
index 000000000000..ea29197646b0
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kasan.c
@@ -0,0 +1,462 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+#include <stdbool.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+
+extern void bpf_kfunc_kasan_poison(void *mem, __u32 mem__sz) __ksym;
+extern void bpf_kfunc_kasan_unpoison(void *mem, __u32 mem__sz) __ksym;
+
+struct bpf_testmod_oob {
+	__u8 data;
+	union {
+		__u8 redzone_1;
+		__u16 redzone_2;
+		__u32 redzone_4;
+		__u64 redzone_8;
+	};
+};
+
+extern struct bpf_testmod_oob *bpf_testmod_oob_alloc(void) __ksym;
+extern void bpf_testmod_oob_free(struct bpf_testmod_oob *oob) __ksym;
+
+int access_size;
+
+struct kasan_test_val {
+	__u8 data_1;
+	__u16 data_2;
+	__u32 data_4;
+	__u64 data_8;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct kasan_test_val);
+} test_map SEC(".maps");
+
+SEC("tcx/ingress")
+int st_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		val.data_1 = 0xAA;
+		break;
+	case 2:
+		val.data_2 = 0xAA;
+		break;
+	case 4:
+		val.data_4 = 0xAA;
+		break;
+	case 8:
+		val.data_8 = 0xAA;
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int st_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		val->data_1 = 0xAA;
+		break;
+	case 2:
+		val->data_2 = 0xAA;
+		break;
+	case 4:
+		val->data_4 = 0xAA;
+		break;
+	case 8:
+		val->data_8 = 0xAA;
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int stx_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		val.data_1 = access_size;
+		break;
+	case 2:
+		val.data_2 = access_size;
+		break;
+	case 4:
+		val.data_4 = access_size;
+		break;
+	case 8:
+		val.data_8 = access_size;
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int stx_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		val->data_1 = access_size;
+		break;
+	case 2:
+		val->data_2 = access_size;
+		break;
+	case 4:
+		val->data_4 = access_size;
+		break;
+	case 8:
+		val->data_8 = access_size;
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int ldx_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__sink(val.data_1);
+		break;
+	case 2:
+		__sink(val.data_2);
+		break;
+	case 4:
+		__sink(val.data_4);
+		break;
+	case 8:
+		__sink(val.data_8);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int ldx_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__sink(val->data_1);
+		break;
+	case 2:
+		__sink(val->data_2);
+		break;
+	case 4:
+		__sink(val->data_4);
+		break;
+	case 8:
+		__sink(val->data_8);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int ldx_patched_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	__sink(val->data_4);
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+
+	return 0;
+}
+
+SEC("tcx/ingress")
+int ldx_patched_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	__sink(val.data_4);
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+
+	return 0;
+}
+
+SEC("tcx/ingress")
+int simple_atomic_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 4:
+		__sync_fetch_and_add(&val.data_4, 4);
+		break;
+	case 8:
+		__sync_fetch_and_add(&val.data_8, 8);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int simple_atomic_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 4:
+		__sync_fetch_and_add(&val->data_4, 4);
+		break;
+	case 8:
+		__sync_fetch_and_add(&val->data_8, 8);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int simple_atomic_fetch_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	__sync_fetch_and_or(&val.data_8, 8);
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int simple_atomic_fetch_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	__sync_fetch_and_or(&val->data_8, 8);
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+bool skip_load_acq_store_rel_tests SEC(".data") = 0;
+
+SEC("tcx/ingress")
+int load_acquire_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__atomic_load_n(&val.data_1, __ATOMIC_ACQUIRE);
+		break;
+	case 2:
+		__atomic_load_n(&val.data_2, __ATOMIC_ACQUIRE);
+		break;
+	case 4:
+		__atomic_load_n(&val.data_4, __ATOMIC_ACQUIRE);
+		break;
+	case 8:
+		__atomic_load_n(&val.data_8, __ATOMIC_ACQUIRE);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int load_acquire_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__atomic_load_n(&val->data_1, __ATOMIC_ACQUIRE);
+		break;
+	case 2:
+		__atomic_load_n(&val->data_2, __ATOMIC_ACQUIRE);
+		break;
+	case 4:
+		__atomic_load_n(&val->data_4, __ATOMIC_ACQUIRE);
+		break;
+	case 8:
+		__atomic_load_n(&val->data_8, __ATOMIC_ACQUIRE);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int store_release_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val val;
+
+	bpf_kfunc_kasan_poison(&val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__atomic_store_n(&val.data_1, 0xAA, __ATOMIC_RELEASE);
+		break;
+	case 2:
+		__atomic_store_n(&val.data_2, 0xBBBB, __ATOMIC_RELEASE);
+		break;
+	case 4:
+		__atomic_store_n(&val.data_4, 0xCCCCCCCC, __ATOMIC_RELEASE);
+		break;
+	case 8:
+		__atomic_store_n(&val.data_8, 0xDDDDDDDDDDDDDDDD,
+				 __ATOMIC_RELEASE);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(&val, sizeof(struct kasan_test_val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int store_release_not_on_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	switch (access_size) {
+	case 1:
+		__atomic_store_n(&val->data_1, 0xAA, __ATOMIC_RELEASE);
+		break;
+	case 2:
+		__atomic_store_n(&val->data_2, 0xBBBB, __ATOMIC_RELEASE);
+		break;
+	case 4:
+		__atomic_store_n(&val->data_4, 0xCCCCCCCC, __ATOMIC_RELEASE);
+		break;
+	case 8:
+		__atomic_store_n(&val->data_8, 0xDDDDDDDDDDDDDDDD,
+				 __ATOMIC_RELEASE);
+		break;
+	}
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+	return 0;
+}
+#else
+bool skip_load_acq_store_rel_tests SEC(".data") = 1;
+#endif
+
+SEC("tcx/ingress")
+int verifier_paths_stack_and_non_stack(struct __sk_buff *skb)
+{
+	struct kasan_test_val stack_val = {};
+	struct kasan_test_val *val;
+	void *ptr;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	if (access_size)
+		ptr = val;
+	else
+		ptr = &stack_val;
+
+	bpf_kfunc_kasan_poison(val, sizeof(*val));
+	*(__u8 *)ptr = 0xAA;
+	bpf_kfunc_kasan_unpoison(val, sizeof(*val));
+	return 0;
+}
+
+SEC("tcx/ingress")
+int ldx_oob(struct __sk_buff *skb)
+{
+	struct bpf_testmod_oob *val;
+	struct kasan_test_val volatile tmp;
+
+	val = bpf_testmod_oob_alloc();
+	if (!val)
+		return 0;
+
+	switch (access_size) {
+	case 1:
+		tmp.data_1 = (__u8)val->redzone_1;
+		break;
+	case 2:
+		tmp.data_2 = (__u16)val->redzone_2;
+		break;
+	case 4:
+		tmp.data_4 = (__u32)val->redzone_4;
+		break;
+	case 8:
+		tmp.data_8 = (__u64)val->redzone_8;
+		break;
+	}
+	bpf_testmod_oob_free(val);
+	return tmp.data_1;
+}
+
+char LICENSE[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/kasan_harden.c b/tools/testing/selftests/bpf/progs/kasan_harden.c
new file mode 100644
index 000000000000..a2756bbfd529
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kasan_harden.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+extern void bpf_kfunc_kasan_poison(void *mem, __u32 mem__sz) __ksym;
+extern void bpf_kfunc_kasan_unpoison(void *mem, __u32 mem__sz) __ksym;
+
+struct kasan_test_val {
+	__u8 data_1;
+	__u16 data_2;
+	__u32 data_4;
+	__u64 data_8;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct kasan_test_val);
+} test_map SEC(".maps");
+
+SEC("tcx/ingress")
+int st_blinded(struct __sk_buff *skb)
+{
+	struct kasan_test_val *val;
+	__u32 key = 0;
+
+	val = bpf_map_lookup_elem(&test_map, &key);
+	if (!val)
+		return 0;
+
+	bpf_kfunc_kasan_poison(val, sizeof(struct kasan_test_val));
+	val->data_1 = 0xAA;
+	bpf_kfunc_kasan_unpoison(val, sizeof(struct kasan_test_val));
+
+	return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index 850cf4f830c4..f5e89ce0ff32 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -75,6 +75,16 @@ union bpf_testmod_union_arg_2 {
 	struct bpf_testmod_struct_arg_2 arg;
 };
 
+struct bpf_testmod_oob {
+	__u8 data;
+	union {
+		__u8 redzone_1;
+		__u16 redzone_2;
+		__u32 redzone_4;
+		__u64 redzone_8;
+	};
+};
+
 __bpf_hook_start();
 
 noinline int
@@ -336,6 +346,47 @@ __bpf_kfunc void bpf_kfunc_put_default_trusted_ptr_test(struct prog_test_member
 	 */
 }
 
+#ifdef CONFIG_BPF_JIT_KASAN
+
+extern void kasan_poison(const void *addr, size_t size, u8 value, bool init);
+
+#define KASAN_SLAB_FREE 0xFB
+
+__bpf_kfunc void bpf_kfunc_kasan_poison(void *mem, u32 mem__sz)
+{
+	kasan_poison(mem, mem__sz, KASAN_SLAB_FREE, false);
+}
+
+__bpf_kfunc void bpf_kfunc_kasan_unpoison(void *mem, u32 mem__sz)
+{
+	kasan_poison(mem, mem__sz, 0x00, false);
+}
+#else
+__bpf_kfunc void bpf_kfunc_kasan_poison(void *mem, u32 mem__sz) { }
+__bpf_kfunc void bpf_kfunc_kasan_unpoison(void *mem, u32 mem__sz) { }
+#endif
+
+__bpf_kfunc struct bpf_testmod_oob *bpf_testmod_oob_alloc(void)
+{
+	struct bpf_testmod_oob *p;
+
+	/*
+	 * Only allocate size of data (and so, voluntarily use kmalloc
+	 * instead of kmalloc_obj), not the rest of the structure, so
+	 * that programs under test trying to access the rest of the
+	 * structure trigger OoB accesses
+	 */
+	p = kmalloc(sizeof(p->data), GFP_ATOMIC);
+	if (!p)
+		return NULL;
+	return p;
+}
+
+__bpf_kfunc void bpf_testmod_oob_free(struct bpf_testmod_oob *oob)
+{
+	kfree(oob);
+}
+
 __bpf_kfunc struct bpf_testmod_ctx *
 bpf_testmod_ctx_create(int *err)
 {
@@ -869,6 +920,10 @@ BTF_ID_FLAGS(func, bpf_testmod_ops3_call_test_arena_stack)
 BTF_ID_FLAGS(func, bpf_testmod_ops3_call_test_arena_multislot)
 BTF_ID_FLAGS(func, bpf_kfunc_get_default_trusted_ptr_test);
 BTF_ID_FLAGS(func, bpf_kfunc_put_default_trusted_ptr_test);
+BTF_ID_FLAGS(func, bpf_kfunc_kasan_poison)
+BTF_ID_FLAGS(func, bpf_kfunc_kasan_unpoison)
+BTF_ID_FLAGS(func, bpf_testmod_oob_alloc, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_testmod_oob_free, KF_RELEASE)
 BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids)
 
 BTF_ID_LIST(bpf_testmod_dtor_ids)

-- 
2.55.0