With write-only excl member removed from struct bpf_map, ops moves to offset 32 and inner_map_meta to offset 40. Update the expected verifier message for the former and retarget the latter at the sha byte array, so the beyond-member-end rejection path stays covered: # LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t verifier_map_ptr [...] #619/5 verifier_map_ptr/bpf_map_ptr: read non-existent field rejected:OK #619/6 verifier_map_ptr/bpf_map_ptr: read non-existent field rejected @unpriv:OK #619/7 verifier_map_ptr/bpf_map_ptr: read beyond sha field rejected:OK #619/8 verifier_map_ptr/bpf_map_ptr: read beyond sha field rejected @unpriv:OK #619/9 verifier_map_ptr/bpf_map_ptr: read ops field accepted:OK #619/10 verifier_map_ptr/bpf_map_ptr: read ops field accepted @unpriv:OK [...] #620 verifier_map_ptr_mixing:OK Summary: 2/20 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann --- .../selftests/bpf/progs/verifier_map_ptr.c | 23 ++++++++++--------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/verifier_map_ptr.c b/tools/testing/selftests/bpf/progs/verifier_map_ptr.c index 166193659870..e0a65835c861 100644 --- a/tools/testing/selftests/bpf/progs/verifier_map_ptr.c +++ b/tools/testing/selftests/bpf/progs/verifier_map_ptr.c @@ -72,14 +72,15 @@ __naked void bpf_map_ptr_write_rejected(void) /* * struct bpf_map starts with the SHA256 hash sha[32] at offset 0 (a readable - * byte array), the u32 excl field at offset 32, and the ops pointer at offset - * 40. Reading a u32 at offset 41 reaches into the middle of the ops pointer, - * i.e. a partial pointer access, which is rejected. + * byte array), followed by the ops pointer at offset 32 and the inner_map_meta + * pointer at offset 40. Reading a u32 at offset 41 reaches into the middle of + * the inner_map_meta pointer, i.e. a partial pointer access, which is + * rejected. */ SEC("socket") __description("bpf_map_ptr: read non-existent field rejected") __failure -__msg("cannot access ptr member ops with moff 40 in struct bpf_map with off 41 size 4") +__msg("cannot access ptr member inner_map_meta with moff 40 in struct bpf_map with off 41 size 4") __failure_unpriv __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN") __flag(BPF_F_ANY_ALIGNMENT) @@ -97,23 +98,23 @@ __naked void read_non_existent_field_rejected(void) } /* - * The u32 excl field spans offsets 32..35 (mend 36). Reading a u32 at offset - * 33 starts inside excl but extends past its end, which the verifier rejects + * The sha byte array spans offsets 0..31 (mend 32). Reading a u32 at offset + * 30 starts inside sha but extends past its end, which the verifier rejects * as an out-of-bounds scalar access. */ SEC("socket") -__description("bpf_map_ptr: read beyond excl field rejected") +__description("bpf_map_ptr: read beyond sha field rejected") __failure -__msg("access beyond the end of member excl (mend:36) in struct bpf_map with off 33 size 4") +__msg("access beyond the end of member sha (mend:32) in struct bpf_map with off 30 size 4") __failure_unpriv __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN") __flag(BPF_F_ANY_ALIGNMENT) -__naked void read_beyond_excl_field_rejected(void) +__naked void read_beyond_sha_field_rejected(void) { asm volatile (" \ r6 = 0; \ r1 = %[map_array_48b] ll; \ - r6 = *(u32*)(r1 + 33); \ + r6 = *(u32*)(r1 + 30); \ r0 = 1; \ exit; \ " : @@ -131,7 +132,7 @@ __naked void ptr_read_ops_field_accepted(void) asm volatile (" \ r6 = 0; \ r1 = %[map_array_48b] ll; \ - r6 = *(u64*)(r1 + 40); \ + r6 = *(u64*)(r1 + 32); \ r0 = 1; \ exit; \ " : -- 2.43.0