Merge branch 'add-kfuncs-bpf_strcasestr-and-bpf_strncasestr'

Rong Tao says:

====================
Add kfuncs bpf_strcasestr and bpf_strncasestr

From: Rong Tao <rongtao@cestc.cn>

Add kfuncs bpf_strcasestr and bpf_strncasestr, which are extensions of
bpf_strstr and bpf_strnstr, suitable for more scenarios.

v4: Fix wrong comment.
v3: keep __bpf_strnstr() static and compress some tests.
    https://lore.kernel.org/lkml/tencent_6E59062E4249590597452A06AFCDA3098808@qq.com/
v2: remove extra __bpf_kfunc and fix comment of bpf_strncasestr().
    https://lore.kernel.org/all/tencent_6D228941AB904DD6E1E58C8ACDEBEC280C06@qq.com/
v1: https://lore.kernel.org/all/tencent_8AF4D15B4475031E2185ACDE4B1495995707@qq.com/
====================

Link: https://patch.msgid.link/tencent_98ABC9680EA2A20198904316DAE5A84AD906@qq.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

5 files changed, 103 insertions, 21 deletions

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index c9fab9a356df..485f65fbd97f 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -3675,34 +3675,21 @@ err_out:
 	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)
+static 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 +3699,13 @@ __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 +3715,7 @@ __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 +3737,69 @@ err_out:
  */
 __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_strncasestr - 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 +4421,9 @@ 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
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..a8513964516b 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
@@ -33,8 +33,11 @@ __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_found(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 +45,12 @@ __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(-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";