[PATCH bpf-next v2 1/2] bpf: add bpf_strcasestr,bpf_strncasestr kfuncs

[PATCH bpf-next v2 1/2] bpf: add bpf_strcasestr,bpf_strncasestr kfuncs

[Rong Tao]

From: Rong Tao <rongtao@cestc.cn>

bpf_strcasestr() and bpf_strncasestr() functions perform same like
bpf_strstr() and bpf_strnstr() except ignoring the case of the
characters.

Signed-off-by: Rong Tao <rongtao@cestc.cn>
---
 kernel/bpf/helpers.c | 96 ++++++++++++++++++++++++++++++++++----------
 1 file changed, 75 insertions(+), 21 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index c9fab9a356df..4df902e5f208 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -3675,34 +3675,20 @@ __bpf_kfunc int bpf_strcspn(const char *s__ign, const char *reject__ign)
 	return -EFAULT;
 }
 
-/**
- * bpf_strnstr - Find the first substring in a length-limited string
- * @s1__ign: The string to be searched
- * @s2__ign: The string to search for
- * @len: the maximum number of characters to search
- *
- * Return:
- * * >=0      - Index of the first character of the first occurrence of @s2__ign
- *              within the first @len characters of @s1__ign
- * * %-ENOENT - @s2__ign not found in the first @len characters of @s1__ign
- * * %-EFAULT - Cannot read one of the strings
- * * %-E2BIG  - One of the strings is too large
- * * %-ERANGE - One of the strings is outside of kernel address space
- */
-__bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len)
+int __bpf_strnstr(const char *s1, const char *s2, size_t len, bool ignore_case)
 {
 	char c1, c2;
 	int i, j;
 
-	if (!copy_from_kernel_nofault_allowed(s1__ign, 1) ||
-	    !copy_from_kernel_nofault_allowed(s2__ign, 1)) {
+	if (!copy_from_kernel_nofault_allowed(s1, 1) ||
+	    !copy_from_kernel_nofault_allowed(s2, 1)) {
 		return -ERANGE;
 	}
 
 	guard(pagefault)();
 	for (i = 0; i < XATTR_SIZE_MAX; i++) {
 		for (j = 0; i + j <= len && j < XATTR_SIZE_MAX; j++) {
-			__get_kernel_nofault(&c2, s2__ign + j, char, err_out);
+			__get_kernel_nofault(&c2, s2 + j, char, err_out);
 			if (c2 == '\0')
 				return i;
 			/*
@@ -3712,7 +3698,13 @@ __bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len
 			 */
 			if (i + j == len)
 				break;
-			__get_kernel_nofault(&c1, s1__ign + j, char, err_out);
+			__get_kernel_nofault(&c1, s1 + j, char, err_out);
+
+			if (ignore_case) {
+				c1 = tolower(c1);
+				c2 = tolower(c2);
+			}
+
 			if (c1 == '\0')
 				return -ENOENT;
 			if (c1 != c2)
@@ -3722,7 +3714,7 @@ __bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len
 			return -E2BIG;
 		if (i + j == len)
 			return -ENOENT;
-		s1__ign++;
+		s1++;
 	}
 	return -E2BIG;
 err_out:
@@ -3744,8 +3736,68 @@ __bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len
  */
 __bpf_kfunc int bpf_strstr(const char *s1__ign, const char *s2__ign)
 {
-	return bpf_strnstr(s1__ign, s2__ign, XATTR_SIZE_MAX);
+	return __bpf_strnstr(s1__ign, s2__ign, XATTR_SIZE_MAX, false);
+}
+
+/**
+ * bpf_strcasestr - Find the first substring in a string, ignoring the case of
+ *                  the characters
+ * @s1__ign: The string to be searched
+ * @s2__ign: The string to search for
+ *
+ * Return:
+ * * >=0      - Index of the first character of the first occurrence of @s2__ign
+ *              within @s1__ign
+ * * %-ENOENT - @s2__ign is not a substring of @s1__ign
+ * * %-EFAULT - Cannot read one of the strings
+ * * %-E2BIG  - One of the strings is too large
+ * * %-ERANGE - One of the strings is outside of kernel address space
+ */
+__bpf_kfunc int bpf_strcasestr(const char *s1__ign, const char *s2__ign)
+{
+	return __bpf_strnstr(s1__ign, s2__ign, XATTR_SIZE_MAX, true);
 }
+
+/**
+ * bpf_strnstr - Find the first substring in a length-limited string
+ * @s1__ign: The string to be searched
+ * @s2__ign: The string to search for
+ * @len: the maximum number of characters to search
+ *
+ * Return:
+ * * >=0      - Index of the first character of the first occurrence of @s2__ign
+ *              within the first @len characters of @s1__ign
+ * * %-ENOENT - @s2__ign not found in the first @len characters of @s1__ign
+ * * %-EFAULT - Cannot read one of the strings
+ * * %-E2BIG  - One of the strings is too large
+ * * %-ERANGE - One of the strings is outside of kernel address space
+ */
+__bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len)
+{
+	return __bpf_strnstr(s1__ign, s2__ign, len, false);
+}
+
+/**
+ * bpf_strnstr - Find the first substring in a length-limited string, ignoring
+ *               the case of the characters
+ * @s1__ign: The string to be searched
+ * @s2__ign: The string to search for
+ * @len: the maximum number of characters to search
+ *
+ * Return:
+ * * >=0      - Index of the first character of the first occurrence of @s2__ign
+ *              within the first @len characters of @s1__ign
+ * * %-ENOENT - @s2__ign not found in the first @len characters of @s1__ign
+ * * %-EFAULT - Cannot read one of the strings
+ * * %-E2BIG  - One of the strings is too large
+ * * %-ERANGE - One of the strings is outside of kernel address space
+ */
+__bpf_kfunc int bpf_strncasestr(const char *s1__ign, const char *s2__ign,
+								size_t len)
+{
+	return __bpf_strnstr(s1__ign, s2__ign, len, true);
+}
+
 #ifdef CONFIG_KEYS
 /**
  * bpf_lookup_user_key - lookup a key by its serial
@@ -4367,7 +4419,9 @@ BTF_ID_FLAGS(func, bpf_strnlen);
 BTF_ID_FLAGS(func, bpf_strspn);
 BTF_ID_FLAGS(func, bpf_strcspn);
 BTF_ID_FLAGS(func, bpf_strstr);
+BTF_ID_FLAGS(func, bpf_strcasestr);
 BTF_ID_FLAGS(func, bpf_strnstr);
+BTF_ID_FLAGS(func, bpf_strncasestr);
 #if defined(CONFIG_BPF_LSM) && defined(CONFIG_CGROUPS)
 BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU)
 #endif
-- 
2.51.0

[PATCH bpf-next v2 2/2] selftests/bpf: Test bpf_strcasestr,bpf_strncasestr kfuncs

[Rong Tao]

From: Rong Tao <rongtao@cestc.cn>

Add tests for new kfuncs bpf_strcasestr() and bpf_strncasestr().

Signed-off-by: Rong Tao <rongtao@cestc.cn>
---
 .../selftests/bpf/prog_tests/string_kfuncs.c        |  2 ++
 .../selftests/bpf/progs/string_kfuncs_failure1.c    | 12 ++++++++++++
 .../selftests/bpf/progs/string_kfuncs_failure2.c    |  2 ++
 .../selftests/bpf/progs/string_kfuncs_success.c     | 13 +++++++++++++
 4 files changed, 29 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
index 4d66fad3c8bd..0f3bf594e7a5 100644
--- a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
+++ b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
@@ -20,7 +20,9 @@ static const char * const test_cases[] = {
 	"strcspn_str",
 	"strcspn_reject",
 	"strstr",
+	"strcasestr",
 	"strnstr",
+	"strncasestr",
 };
 
 void run_too_long_tests(void)
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
index 99d72c68f76a..826e6b6aff7e 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
@@ -45,8 +45,12 @@ SEC("syscall")  __retval(USER_PTR_ERR)int test_strcspn_null1(void *ctx) { return
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strcspn_null2(void *ctx) { return bpf_strcspn("hello", NULL); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strstr_null1(void *ctx) { return bpf_strstr(NULL, "hello"); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strstr_null2(void *ctx) { return bpf_strstr("hello", NULL); }
+SEC("syscall")  __retval(USER_PTR_ERR)int test_strcasestr_null1(void *ctx) { return bpf_strcasestr(NULL, "hello"); }
+SEC("syscall")  __retval(USER_PTR_ERR)int test_strcasestr_null2(void *ctx) { return bpf_strcasestr("hello", NULL); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strnstr_null1(void *ctx) { return bpf_strnstr(NULL, "hello", 1); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strnstr_null2(void *ctx) { return bpf_strnstr("hello", NULL, 1); }
+SEC("syscall")  __retval(USER_PTR_ERR)int test_strncasestr_null1(void *ctx) { return bpf_strncasestr(NULL, "hello", 1); }
+SEC("syscall")  __retval(USER_PTR_ERR)int test_strncasestr_null2(void *ctx) { return bpf_strncasestr("hello", NULL, 1); }
 
 /* Passing userspace ptr to string kfuncs */
 SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr1(void *ctx) { return bpf_strcmp(user_ptr, "hello"); }
@@ -65,8 +69,12 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strcspn_user_ptr1(void *ctx) { re
 SEC("syscall") __retval(USER_PTR_ERR) int test_strcspn_user_ptr2(void *ctx) { return bpf_strcspn("hello", user_ptr); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strstr_user_ptr1(void *ctx) { return bpf_strstr(user_ptr, "hello"); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strstr_user_ptr2(void *ctx) { return bpf_strstr("hello", user_ptr); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strcasestr_user_ptr1(void *ctx) { return bpf_strcasestr(user_ptr, "hello"); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strcasestr_user_ptr2(void *ctx) { return bpf_strcasestr("hello", user_ptr); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strnstr_user_ptr1(void *ctx) { return bpf_strnstr(user_ptr, "hello", 1); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strnstr_user_ptr2(void *ctx) { return bpf_strnstr("hello", user_ptr, 1); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strncasestr_user_ptr1(void *ctx) { return bpf_strncasestr(user_ptr, "hello", 1); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strncasestr_user_ptr2(void *ctx) { return bpf_strncasestr("hello", user_ptr, 1); }
 
 #endif /* __TARGET_ARCH_s390 */
 
@@ -87,7 +95,11 @@ SEC("syscall") __retval(-EFAULT) int test_strcspn_pagefault1(void *ctx) { return
 SEC("syscall") __retval(-EFAULT) int test_strcspn_pagefault2(void *ctx) { return bpf_strcspn("hello", invalid_kern_ptr); }
 SEC("syscall") __retval(-EFAULT) int test_strstr_pagefault1(void *ctx) { return bpf_strstr(invalid_kern_ptr, "hello"); }
 SEC("syscall") __retval(-EFAULT) int test_strstr_pagefault2(void *ctx) { return bpf_strstr("hello", invalid_kern_ptr); }
+SEC("syscall") __retval(-EFAULT) int test_strcasestr_pagefault1(void *ctx) { return bpf_strcasestr(invalid_kern_ptr, "hello"); }
+SEC("syscall") __retval(-EFAULT) int test_strcasestr_pagefault2(void *ctx) { return bpf_strcasestr("hello", invalid_kern_ptr); }
 SEC("syscall") __retval(-EFAULT) int test_strnstr_pagefault1(void *ctx) { return bpf_strnstr(invalid_kern_ptr, "hello", 1); }
 SEC("syscall") __retval(-EFAULT) int test_strnstr_pagefault2(void *ctx) { return bpf_strnstr("hello", invalid_kern_ptr, 1); }
+SEC("syscall") __retval(-EFAULT) int test_strncasestr_pagefault1(void *ctx) { return bpf_strncasestr(invalid_kern_ptr, "hello", 1); }
+SEC("syscall") __retval(-EFAULT) int test_strncasestr_pagefault2(void *ctx) { return bpf_strncasestr("hello", invalid_kern_ptr, 1); }
 
 char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
index e41cc5601994..05e1da1f250f 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
@@ -19,6 +19,8 @@ SEC("syscall") int test_strspn_accept_too_long(void *ctx) { return bpf_strspn("b
 SEC("syscall") int test_strcspn_str_too_long(void *ctx) { return bpf_strcspn(long_str, "b"); }
 SEC("syscall") int test_strcspn_reject_too_long(void *ctx) { return bpf_strcspn("b", long_str); }
 SEC("syscall") int test_strstr_too_long(void *ctx) { return bpf_strstr(long_str, "hello"); }
+SEC("syscall") int test_strcasestr_too_long(void *ctx) { return bpf_strcasestr(long_str, "hello"); }
 SEC("syscall") int test_strnstr_too_long(void *ctx) { return bpf_strnstr(long_str, "hello", sizeof(long_str)); }
+SEC("syscall") int test_strncasestr_too_long(void *ctx) { return bpf_strncasestr(long_str, "hello", sizeof(long_str)); }
 
 char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
index 2e3498e37b9c..d21330b4cc3b 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
@@ -33,8 +33,12 @@ __test(11) int test_strnlen(void *ctx) { return bpf_strnlen(str, 12); }
 __test(5) int test_strspn(void *ctx) { return bpf_strspn(str, "ehlo"); }
 __test(2) int test_strcspn(void *ctx) { return bpf_strcspn(str, "lo"); }
 __test(6) int test_strstr_found(void *ctx) { return bpf_strstr(str, "world"); }
+__test(6) int test_strcasestr_found1(void *ctx) { return bpf_strcasestr(str, "world"); }
+__test(6) int test_strcasestr_found2(void *ctx) { return bpf_strcasestr(str, "WORLD"); }
 __test(-ENOENT) int test_strstr_notfound(void *ctx) { return bpf_strstr(str, "hi"); }
+__test(-ENOENT) int test_strcasestr_notfound(void *ctx) { return bpf_strcasestr(str, "hi"); }
 __test(0) int test_strstr_empty(void *ctx) { return bpf_strstr(str, ""); }
+__test(0) int test_strcasestr_empty(void *ctx) { return bpf_strcasestr(str, ""); }
 __test(0) int test_strnstr_found1(void *ctx) { return bpf_strnstr("", "", 0); }
 __test(0) int test_strnstr_found2(void *ctx) { return bpf_strnstr(str, "hello", 5); }
 __test(0) int test_strnstr_found3(void *ctx) { return bpf_strnstr(str, "hello", 6); }
@@ -42,5 +46,14 @@ __test(-ENOENT) int test_strnstr_notfound1(void *ctx) { return bpf_strnstr(str,
 __test(-ENOENT) int test_strnstr_notfound2(void *ctx) { return bpf_strnstr(str, "hello", 4); }
 __test(-ENOENT) int test_strnstr_notfound3(void *ctx) { return bpf_strnstr("", "a", 0); }
 __test(0) int test_strnstr_empty(void *ctx) { return bpf_strnstr(str, "", 1); }
+__test(0) int test_strncasestr_found1(void *ctx) { return bpf_strncasestr("", "", 0); }
+__test(0) int test_strncasestr_found2(void *ctx) { return bpf_strncasestr(str, "hello", 5); }
+__test(0) int test_strncasestr_found3(void *ctx) { return bpf_strncasestr(str, "hello", 6); }
+__test(0) int test_strncasestr_found4(void *ctx) { return bpf_strncasestr(str, "HELLO", 5); }
+__test(0) int test_strncasestr_found5(void *ctx) { return bpf_strncasestr(str, "HELLO", 6); }
+__test(-ENOENT) int test_strncasestr_notfound1(void *ctx) { return bpf_strncasestr(str, "hi", 10); }
+__test(-ENOENT) int test_strncasestr_notfound2(void *ctx) { return bpf_strncasestr(str, "hello", 4); }
+__test(-ENOENT) int test_strncasestr_notfound3(void *ctx) { return bpf_strncasestr("", "a", 0); }
+__test(0) int test_strncasestr_empty(void *ctx) { return bpf_strncasestr(str, "", 1); }
 
 char _license[] SEC("license") = "GPL";
-- 
2.51.0

Re: [PATCH bpf-next v2 1/2] bpf: add bpf_strcasestr,bpf_strncasestr kfuncs

[Andrii Nakryiko]

On Sat, Oct 4, 2025 at 7:52 AM Rong Tao <rtoax@foxmail.com> wrote:
>
> From: Rong Tao <rongtao@cestc.cn>
>
> bpf_strcasestr() and bpf_strncasestr() functions perform same like
> bpf_strstr() and bpf_strnstr() except ignoring the case of the
> characters.
>
> Signed-off-by: Rong Tao <rongtao@cestc.cn>
> ---
>  kernel/bpf/helpers.c | 96 ++++++++++++++++++++++++++++++++++----------
>  1 file changed, 75 insertions(+), 21 deletions(-)
>
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index c9fab9a356df..4df902e5f208 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -3675,34 +3675,20 @@ __bpf_kfunc int bpf_strcspn(const char *s__ign, const char *reject__ign)
>         return -EFAULT;
>  }
>
> -/**
> - * bpf_strnstr - Find the first substring in a length-limited string
> - * @s1__ign: The string to be searched
> - * @s2__ign: The string to search for
> - * @len: the maximum number of characters to search
> - *
> - * Return:
> - * * >=0      - Index of the first character of the first occurrence of @s2__ign
> - *              within the first @len characters of @s1__ign
> - * * %-ENOENT - @s2__ign not found in the first @len characters of @s1__ign
> - * * %-EFAULT - Cannot read one of the strings
> - * * %-E2BIG  - One of the strings is too large
> - * * %-ERANGE - One of the strings is outside of kernel address space
> - */
> -__bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len)
> +int __bpf_strnstr(const char *s1, const char *s2, size_t len, bool ignore_case)

keep it static?

pw-bot: cr


[...]

Re: [PATCH bpf-next v2 2/2] selftests/bpf: Test bpf_strcasestr,bpf_strncasestr kfuncs

[Eduard Zingerman]

On Sat, 2025-10-04 at 22:47 +0800, Rong Tao wrote:
> From: Rong Tao <rongtao@cestc.cn>
> 
> Add tests for new kfuncs bpf_strcasestr() and bpf_strncasestr().
> 
> Signed-off-by: Rong Tao <rongtao@cestc.cn>
> ---

Acked-by: Eduard Zingerman <eddyz87@gmail.com>

[...]

> diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
> index 2e3498e37b9c..d21330b4cc3b 100644
> --- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
> +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
> @@ -33,8 +33,12 @@ __test(11) int test_strnlen(void *ctx) { return bpf_strnlen(str, 12); }
>  __test(5) int test_strspn(void *ctx) { return bpf_strspn(str, "ehlo"); }
>  __test(2) int test_strcspn(void *ctx) { return bpf_strcspn(str, "lo"); }
>  __test(6) int test_strstr_found(void *ctx) { return bpf_strstr(str, "world"); }
> +__test(6) int test_strcasestr_found1(void *ctx) { return bpf_strcasestr(str, "world"); }
> +__test(6) int test_strcasestr_found2(void *ctx) { return bpf_strcasestr(str, "WORLD"); }

Nit: I'd compress these two tests into one:
     __test(6) int test_strcasestr_found1(void *ctx) { return bpf_strcasestr(str, "woRLD"); }
     (and did the same for (str, "hello") variants below).

>  __test(-ENOENT) int test_strstr_notfound(void *ctx) { return bpf_strstr(str, "hi"); }
> +__test(-ENOENT) int test_strcasestr_notfound(void *ctx) { return bpf_strcasestr(str, "hi"); }
>  __test(0) int test_strstr_empty(void *ctx) { return bpf_strstr(str, ""); }
> +__test(0) int test_strcasestr_empty(void *ctx) { return bpf_strcasestr(str, ""); }
>  __test(0) int test_strnstr_found1(void *ctx) { return bpf_strnstr("", "", 0); }
>  __test(0) int test_strnstr_found2(void *ctx) { return bpf_strnstr(str, "hello", 5); }
>  __test(0) int test_strnstr_found3(void *ctx) { return bpf_strnstr(str, "hello", 6); }
> @@ -42,5 +46,14 @@ __test(-ENOENT) int test_strnstr_notfound1(void *ctx) { return bpf_strnstr(str,
>  __test(-ENOENT) int test_strnstr_notfound2(void *ctx) { return bpf_strnstr(str, "hello", 4); }
>  __test(-ENOENT) int test_strnstr_notfound3(void *ctx) { return bpf_strnstr("", "a", 0); }
>  __test(0) int test_strnstr_empty(void *ctx) { return bpf_strnstr(str, "", 1); }
> +__test(0) int test_strncasestr_found1(void *ctx) { return bpf_strncasestr("", "", 0); }
> +__test(0) int test_strncasestr_found2(void *ctx) { return bpf_strncasestr(str, "hello", 5); }
> +__test(0) int test_strncasestr_found3(void *ctx) { return bpf_strncasestr(str, "hello", 6); }
> +__test(0) int test_strncasestr_found4(void *ctx) { return bpf_strncasestr(str, "HELLO", 5); }
> +__test(0) int test_strncasestr_found5(void *ctx) { return bpf_strncasestr(str, "HELLO", 6); }
> +__test(-ENOENT) int test_strncasestr_notfound1(void *ctx) { return bpf_strncasestr(str, "hi", 10); }
> +__test(-ENOENT) int test_strncasestr_notfound2(void *ctx) { return bpf_strncasestr(str, "hello", 4); }
> +__test(-ENOENT) int test_strncasestr_notfound3(void *ctx) { return bpf_strncasestr("", "a", 0); }
> +__test(0) int test_strncasestr_empty(void *ctx) { return bpf_strncasestr(str, "", 1); }
>  
>  char _license[] SEC("license") = "GPL";

Re: [PATCH bpf-next v2 1/2] bpf: add bpf_strcasestr,bpf_strncasestr kfuncs

[rtoax]

On 10/7/25 7:23 AM, Andrii Nakryiko wrote:
> On Sat, Oct 4, 2025 at 7:52 AM Rong Tao <rtoax@foxmail.com> wrote:
>> From: Rong Tao <rongtao@cestc.cn>
>>
>> bpf_strcasestr() and bpf_strncasestr() functions perform same like
>> bpf_strstr() and bpf_strnstr() except ignoring the case of the
>> characters.
>>
>> Signed-off-by: Rong Tao <rongtao@cestc.cn>
>> ---
>>   kernel/bpf/helpers.c | 96 ++++++++++++++++++++++++++++++++++----------
>>   1 file changed, 75 insertions(+), 21 deletions(-)
>>
>> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
>> index c9fab9a356df..4df902e5f208 100644
>> --- a/kernel/bpf/helpers.c
>> +++ b/kernel/bpf/helpers.c
>> @@ -3675,34 +3675,20 @@ __bpf_kfunc int bpf_strcspn(const char *s__ign, const char *reject__ign)
>>          return -EFAULT;
>>   }
>>
>> -/**
>> - * bpf_strnstr - Find the first substring in a length-limited string
>> - * @s1__ign: The string to be searched
>> - * @s2__ign: The string to search for
>> - * @len: the maximum number of characters to search
>> - *
>> - * Return:
>> - * * >=0      - Index of the first character of the first occurrence of @s2__ign
>> - *              within the first @len characters of @s1__ign
>> - * * %-ENOENT - @s2__ign not found in the first @len characters of @s1__ign
>> - * * %-EFAULT - Cannot read one of the strings
>> - * * %-E2BIG  - One of the strings is too large
>> - * * %-ERANGE - One of the strings is outside of kernel address space
>> - */
>> -__bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len)
>> +int __bpf_strnstr(const char *s1, const char *s2, size_t len, bool ignore_case)
> keep it static?

Thanks, fixed in v3, please review.

Rong Tao

>
> pw-bot: cr
>
>
> [...]

Re: [PATCH bpf-next v2 2/2] selftests/bpf: Test bpf_strcasestr,bpf_strncasestr kfuncs

[rtoax]

On 10/7/25 8:29 AM, Eduard Zingerman wrote:
> On Sat, 2025-10-04 at 22:47 +0800, Rong Tao wrote:
>> From: Rong Tao <rongtao@cestc.cn>
>>
>> Add tests for new kfuncs bpf_strcasestr() and bpf_strncasestr().
>>
>> Signed-off-by: Rong Tao <rongtao@cestc.cn>
>> ---
> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
>
> [...]
>
>> diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
>> index 2e3498e37b9c..d21330b4cc3b 100644
>> --- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
>> +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
>> @@ -33,8 +33,12 @@ __test(11) int test_strnlen(void *ctx) { return bpf_strnlen(str, 12); }
>>   __test(5) int test_strspn(void *ctx) { return bpf_strspn(str, "ehlo"); }
>>   __test(2) int test_strcspn(void *ctx) { return bpf_strcspn(str, "lo"); }
>>   __test(6) int test_strstr_found(void *ctx) { return bpf_strstr(str, "world"); }
>> +__test(6) int test_strcasestr_found1(void *ctx) { return bpf_strcasestr(str, "world"); }
>> +__test(6) int test_strcasestr_found2(void *ctx) { return bpf_strcasestr(str, "WORLD"); }
> Nit: I'd compress these two tests into one:
>       __test(6) int test_strcasestr_found1(void *ctx) { return bpf_strcasestr(str, "woRLD"); }
>       (and did the same for (str, "hello") variants below).

I just submit v3, please review, thanks.

Rong Tao

>
>>   __test(-ENOENT) int test_strstr_notfound(void *ctx) { return bpf_strstr(str, "hi"); }
>> +__test(-ENOENT) int test_strcasestr_notfound(void *ctx) { return bpf_strcasestr(str, "hi"); }
>>   __test(0) int test_strstr_empty(void *ctx) { return bpf_strstr(str, ""); }
>> +__test(0) int test_strcasestr_empty(void *ctx) { return bpf_strcasestr(str, ""); }
>>   __test(0) int test_strnstr_found1(void *ctx) { return bpf_strnstr("", "", 0); }
>>   __test(0) int test_strnstr_found2(void *ctx) { return bpf_strnstr(str, "hello", 5); }
>>   __test(0) int test_strnstr_found3(void *ctx) { return bpf_strnstr(str, "hello", 6); }
>> @@ -42,5 +46,14 @@ __test(-ENOENT) int test_strnstr_notfound1(void *ctx) { return bpf_strnstr(str,
>>   __test(-ENOENT) int test_strnstr_notfound2(void *ctx) { return bpf_strnstr(str, "hello", 4); }
>>   __test(-ENOENT) int test_strnstr_notfound3(void *ctx) { return bpf_strnstr("", "a", 0); }
>>   __test(0) int test_strnstr_empty(void *ctx) { return bpf_strnstr(str, "", 1); }
>> +__test(0) int test_strncasestr_found1(void *ctx) { return bpf_strncasestr("", "", 0); }
>> +__test(0) int test_strncasestr_found2(void *ctx) { return bpf_strncasestr(str, "hello", 5); }
>> +__test(0) int test_strncasestr_found3(void *ctx) { return bpf_strncasestr(str, "hello", 6); }
>> +__test(0) int test_strncasestr_found4(void *ctx) { return bpf_strncasestr(str, "HELLO", 5); }
>> +__test(0) int test_strncasestr_found5(void *ctx) { return bpf_strncasestr(str, "HELLO", 6); }
>> +__test(-ENOENT) int test_strncasestr_notfound1(void *ctx) { return bpf_strncasestr(str, "hi", 10); }
>> +__test(-ENOENT) int test_strncasestr_notfound2(void *ctx) { return bpf_strncasestr(str, "hello", 4); }
>> +__test(-ENOENT) int test_strncasestr_notfound3(void *ctx) { return bpf_strncasestr("", "a", 0); }
>> +__test(0) int test_strncasestr_empty(void *ctx) { return bpf_strncasestr(str, "", 1); }
>>   
>>   char _license[] SEC("license") = "GPL";