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bpf: add bpf_strcasecmp kfunc

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bpf_strcasecmp() function performs same like bpf_strcmp() except ignoring
the case of the characters.

Signed-off-by: Rong Tao <rongtao@cestc.cn>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Viktor Malik <vmalik@redhat.com>
Link: https://lore.kernel.org/r/tencent_292BD3682A628581AA904996D8E59F4ACD06@qq.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Rong Tao
2025-09-03 07:47:10 +08:00
committed by Alexei Starovoitov
parent 525ac69b1e
commit 19559e8441
1 changed files with 49 additions and 21 deletions
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70
kernel/bpf/helpers.c
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@@ -3349,6 +3349,36 @@ __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)
{
char c1, c2;
int i;
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++) {
__get_kernel_nofault(&c1, s1, char, err_out);
__get_kernel_nofault(&c2, s2, char, err_out);
if (ignore_case) {
c1 = tolower(c1);
c2 = tolower(c2);
}
if (c1 != c2)
return c1 < c2 ? -1 : 1;
if (c1 == '\0')
return 0;
s1++;
s2++;
}
return -E2BIG;
err_out:
return -EFAULT;
}
/**
* bpf_strcmp - Compare two strings
* @s1__ign: One string
@@ -3364,28 +3394,25 @@ __bpf_kfunc void __bpf_trap(void)
*/
__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
{
char c1, c2;
int i;
return __bpf_strcasecmp(s1__ign, s2__ign, false);
}
if (!copy_from_kernel_nofault_allowed(s1__ign, 1) ||
!copy_from_kernel_nofault_allowed(s2__ign, 1)) {
return -ERANGE;
}
guard(pagefault)();
for (i = 0; i < XATTR_SIZE_MAX; i++) {
__get_kernel_nofault(&c1, s1__ign, char, err_out);
__get_kernel_nofault(&c2, s2__ign, char, err_out);
if (c1 != c2)
return c1 < c2 ? -1 : 1;
if (c1 == '\0')
return 0;
s1__ign++;
s2__ign++;
}
return -E2BIG;
err_out:
return -EFAULT;
/**
* bpf_strcasecmp - Compare two strings, ignoring the case of the characters
* @s1__ign: One string
* @s2__ign: Another string
*
* 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_strcasecmp(const char *s1__ign, const char *s2__ign)
{
return __bpf_strcasecmp(s1__ign, s2__ign, true);
}
/**
@@ -3832,6 +3859,7 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE)
#endif
BTF_ID_FLAGS(func, __bpf_trap)
BTF_ID_FLAGS(func, bpf_strcmp);
BTF_ID_FLAGS(func, bpf_strcasecmp);
BTF_ID_FLAGS(func, bpf_strchr);
BTF_ID_FLAGS(func, bpf_strchrnul);
BTF_ID_FLAGS(func, bpf_strnchr);