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bpf: add bpf_strcasestr,bpf_strncasestr kfuncs

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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>
Link: https://lore.kernel.org/r/tencent_B01165355D42A8B8BF5E8D0A21EE1A88090A@qq.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Rong Tao
2025-10-09 09:22:25 +08:00
committed by Alexei Starovoitov
parent 17566cf0e3
commit b5b693f735
1 changed files with 77 additions and 21 deletions
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98
kernel/bpf/helpers.c
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@@ -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