bpf_strncasecmp() function performs same like bpf_strcasecmp() except limiting the comparison to a specific length. Signed-off-by: Yuzuki Ishiyama --- kernel/bpf/helpers.c | 37 ++++++++++++++++++++++++++++++++----- 1 file changed, 32 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9eaa4185e0a7..bdd76209cfcf 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3406,18 +3406,23 @@ __bpf_kfunc void __bpf_trap(void) * __get_kernel_nofault instead of plain dereference to make them safe. */ -static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case) +static int __bpf_strncasecmp(const char *s1, const char *s2, bool ignore_case, size_t len) { char c1, c2; - int i; + int i, max_sz; if (!copy_from_kernel_nofault_allowed(s1, 1) || !copy_from_kernel_nofault_allowed(s2, 1)) { return -ERANGE; } + if (len == 0) + return 0; + + max_sz = min_t(int, len, XATTR_SIZE_MAX); + guard(pagefault)(); - for (i = 0; i < XATTR_SIZE_MAX; i++) { + for (i = 0; i < max_sz; i++) { __get_kernel_nofault(&c1, s1, char, err_out); __get_kernel_nofault(&c2, s2, char, err_out); if (ignore_case) { @@ -3431,6 +3436,8 @@ static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case) s1++; s2++; } + if (len < XATTR_SIZE_MAX) + return 0; return -E2BIG; err_out: return -EFAULT; @@ -3451,7 +3458,7 @@ static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case) */ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) { - return __bpf_strcasecmp(s1__ign, s2__ign, false); + return __bpf_strncasecmp(s1__ign, s2__ign, false, XATTR_SIZE_MAX); } /** @@ -3469,7 +3476,26 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) */ __bpf_kfunc int bpf_strcasecmp(const char *s1__ign, const char *s2__ign) { - return __bpf_strcasecmp(s1__ign, s2__ign, true); + return __bpf_strncasecmp(s1__ign, s2__ign, true, XATTR_SIZE_MAX); +} + +/* + * bpf_strncasecmp - Compare two length-limited strings, ignoring case + * @s1__ign: One string + * @s2__ign: Another string + * @len: The maximum number of characters to compare (limited by XATTR_SIZE_MAX) + + * Return: + * * %0 - Strings are equal + * * %-1 - @s1__ign is smaller + * * %1 - @s2__ign is smaller + * * %-EFAULT - Cannot read one of the strings + * * %-E2BIG - One of strings is too large + * * %-ERANGE - One of strings is outside of kernel address space + */ +__bpf_kfunc int bpf_strncasecmp(const char *s1__ign, const char *s2__ign, size_t len) +{ + return __bpf_strncasecmp(s1__ign, s2__ign, true, len); } /** @@ -4521,6 +4547,7 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) BTF_ID_FLAGS(func, __bpf_trap) BTF_ID_FLAGS(func, bpf_strcmp); BTF_ID_FLAGS(func, bpf_strcasecmp); +BTF_ID_FLAGS(func, bpf_strncasecmp); BTF_ID_FLAGS(func, bpf_strchr); BTF_ID_FLAGS(func, bpf_strchrnul); BTF_ID_FLAGS(func, bpf_strnchr); -- 2.52.0 Add testsuites for kfunc bpf_strncasecmp. Signed-off-by: Yuzuki Ishiyama --- tools/testing/selftests/bpf/prog_tests/string_kfuncs.c | 1 + tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c | 6 ++++++ tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c | 1 + tools/testing/selftests/bpf/progs/string_kfuncs_success.c | 7 +++++++ 4 files changed, 15 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c index 0f3bf594e7a5..300032a19445 100644 --- a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c +++ b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c @@ -9,6 +9,7 @@ static const char * const test_cases[] = { "strcmp", "strcasecmp", + "strncasecmp", "strchr", "strchrnul", "strnchr", diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c index 826e6b6aff7e..bddc4e8579d2 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c @@ -33,6 +33,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_null1(void *ctx) { return SEC("syscall") __retval(USER_PTR_ERR)int test_strcmp_null2(void *ctx) { return bpf_strcmp("hello", NULL); } SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_null1(void *ctx) { return bpf_strcasecmp(NULL, "HELLO"); } SEC("syscall") __retval(USER_PTR_ERR)int test_strcasecmp_null2(void *ctx) { return bpf_strcasecmp("HELLO", NULL); } +SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null1(void *ctx) { return bpf_strncasecmp(NULL, "HELLO", 5); } +SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null2(void *ctx) { return bpf_strncasecmp("HELLO", NULL, 5); } SEC("syscall") __retval(USER_PTR_ERR)int test_strchr_null(void *ctx) { return bpf_strchr(NULL, 'a'); } SEC("syscall") __retval(USER_PTR_ERR)int test_strchrnul_null(void *ctx) { return bpf_strchrnul(NULL, 'a'); } SEC("syscall") __retval(USER_PTR_ERR)int test_strnchr_null(void *ctx) { return bpf_strnchr(NULL, 1, 'a'); } @@ -57,6 +59,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr1(void *ctx) { ret SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr2(void *ctx) { return bpf_strcmp("hello", user_ptr); } SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr1(void *ctx) { return bpf_strcasecmp(user_ptr, "HELLO"); } SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr2(void *ctx) { return bpf_strcasecmp("HELLO", user_ptr); } +SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr1(void *ctx) { return bpf_strncasecmp(user_ptr, "HELLO", 5); } +SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr2(void *ctx) { return bpf_strncasecmp("HELLO", user_ptr, 5); } SEC("syscall") __retval(USER_PTR_ERR) int test_strchr_user_ptr(void *ctx) { return bpf_strchr(user_ptr, 'a'); } SEC("syscall") __retval(USER_PTR_ERR) int test_strchrnul_user_ptr(void *ctx) { return bpf_strchrnul(user_ptr, 'a'); } SEC("syscall") __retval(USER_PTR_ERR) int test_strnchr_user_ptr(void *ctx) { return bpf_strnchr(user_ptr, 1, 'a'); } @@ -83,6 +87,8 @@ SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault1(void *ctx) { return SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault2(void *ctx) { return bpf_strcmp("hello", invalid_kern_ptr); } SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault1(void *ctx) { return bpf_strcasecmp(invalid_kern_ptr, "HELLO"); } SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault2(void *ctx) { return bpf_strcasecmp("HELLO", invalid_kern_ptr); } +SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault1(void *ctx) { return bpf_strncasecmp(invalid_kern_ptr, "HELLO", 5); } +SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault2(void *ctx) { return bpf_strncasecmp("HELLO", invalid_kern_ptr, 5); } SEC("syscall") __retval(-EFAULT) int test_strchr_pagefault(void *ctx) { return bpf_strchr(invalid_kern_ptr, 'a'); } SEC("syscall") __retval(-EFAULT) int test_strchrnul_pagefault(void *ctx) { return bpf_strchrnul(invalid_kern_ptr, 'a'); } SEC("syscall") __retval(-EFAULT) int test_strnchr_pagefault(void *ctx) { return bpf_strnchr(invalid_kern_ptr, 1, 'a'); } diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c index 05e1da1f250f..412c53b87b18 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c @@ -8,6 +8,7 @@ char long_str[XATTR_SIZE_MAX + 1]; SEC("syscall") int test_strcmp_too_long(void *ctx) { return bpf_strcmp(long_str, long_str); } SEC("syscall") int test_strcasecmp_too_long(void *ctx) { return bpf_strcasecmp(long_str, long_str); } +SEC("syscall") int test_strncasecmp_too_long(void *ctx) { return bpf_strncasecmp(long_str, long_str, sizeof(long_str)); } SEC("syscall") int test_strchr_too_long(void *ctx) { return bpf_strchr(long_str, 'b'); } SEC("syscall") int test_strchrnul_too_long(void *ctx) { return bpf_strchrnul(long_str, 'b'); } SEC("syscall") int test_strnchr_too_long(void *ctx) { return bpf_strnchr(long_str, sizeof(long_str), 'b'); } diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c index a8513964516b..3ccfae4d27d3 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c @@ -17,6 +17,13 @@ __test(0) int test_strcasecmp_eq2(void *ctx) { return bpf_strcasecmp(str, "HELLO __test(0) int test_strcasecmp_eq3(void *ctx) { return bpf_strcasecmp(str, "HELLO world"); } __test(1) int test_strcasecmp_neq1(void *ctx) { return bpf_strcasecmp(str, "hello"); } __test(1) int test_strcasecmp_neq2(void *ctx) { return bpf_strcasecmp(str, "HELLO"); } +__test(0) int test_strncasecmp_eq1(void *ctx) { return bpf_strncasecmp(str, "hello world", 11); } +__test(0) int test_strncasecmp_eq2(void *ctx) { return bpf_strncasecmp(str, "HELLO WORLD", 11); } +__test(0) int test_strncasecmp_eq3(void *ctx) { return bpf_strncasecmp(str, "HELLO world", 11); } +__test(0) int test_strncasecmp_eq4(void *ctx) { return bpf_strncasecmp(str, "hello", 5); } +__test(0) int test_strncasecmp_eq6(void *ctx) { return bpf_strncasecmp(str, "hello world!", 11); } +__test(-1) int test_strncasecmp_neq1(void *ctx) { return bpf_strncasecmp(str, "hello!", 6); } +__test(1) int test_strncasecmp_neq2(void *ctx) { return bpf_strncasecmp(str, "abc", 3); } __test(1) int test_strchr_found(void *ctx) { return bpf_strchr(str, 'e'); } __test(11) int test_strchr_null(void *ctx) { return bpf_strchr(str, '\0'); } __test(-ENOENT) int test_strchr_notfound(void *ctx) { return bpf_strchr(str, 'x'); } -- 2.52.0