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 | 97 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 76 insertions(+), 21 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index c9fab9a356df..db319aa61c3f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3675,34 +3675,21 @@ __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) +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 +3737,68 @@ __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 +4420,9 @@ 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