torvalds/linux
3
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-03-22 07:27:12 +08:00
Code Issues Packages Projects Releases Wiki Activity

Merge branch 'bpf-add-kfunc-bpf_strncasecmp'

Browse Source 
Yuzuki Ishiyama says:

====================
bpf: Add kfunc bpf_strncasecmp()

This patchset introduces bpf_strncasecmp to allow case-insensitive and
limited-length string comparison. This is useful for parsing protocol
headers like HTTP.
---

Changes in v5:
- Fixed the test function numbering

Changes in v4:
- Updated the loop variable to maintain style consistency

Changes in v3:
- Use ternary operator to maintain style consistency
- Reverted unnecessary doc comment about XATTR_SIZE_MAX

Changes in v2:
- Compute max_sz upfront and remove len check from the loop body
- Document that @len is limited by XATTR_SIZE_MAX
====================

Link: https://patch.msgid.link/20260121033328.1850010-1-ishiyama@hpc.is.uec.ac.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov
2026-01-21 09:42:53 -08:00
parent d0f5d4f8f3 f4924ad0b1
commit d73cbe2c14
5 changed files with 40 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
kernel/bpf/helpers.c
View File

@@ -3413,7 +3413,7 @@ __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)
static int __bpf_strncasecmp(const char *s1, const char *s2, bool ignore_case, size_t len)
{
char c1, c2;
int i;
@@ -3424,7 +3424,7 @@ static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case)
}
guard(pagefault)();
for (i = 0; i < XATTR_SIZE_MAX; i++) {
for (i = 0; i < len && i < XATTR_SIZE_MAX; i++) {
__get_kernel_nofault(&c1, s1, char, err_out);
__get_kernel_nofault(&c2, s2, char, err_out);
if (ignore_case) {
@@ -3438,7 +3438,7 @@ static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case)
s1++;
s2++;
}
return -E2BIG;
return i == XATTR_SIZE_MAX ? -E2BIG : 0;
err_out:
return -EFAULT;
}
@@ -3458,7 +3458,7 @@ err_out:
*/
__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
{
return __bpf_strcasecmp(s1__ign, s2__ign, false);
return __bpf_strncasecmp(s1__ign, s2__ign, false, XATTR_SIZE_MAX);
}
/**
@@ -3476,7 +3476,26 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
*/
__bpf_kfunc int bpf_strcasecmp(const char *s1__ign, const char *s2__ign)
{
return __bpf_strcasecmp(s1__ign, s2__ign, true);
return __bpf_strncasecmp(s1__ign, s2__ign, true, XATTR_SIZE_MAX);
}
/*
* bpf_strncasecmp - Compare two length-limited strings, ignoring case
* @s1__ign: One string
* @s2__ign: Another string
* @len: The maximum number of characters to compare
*
* 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_strncasecmp(const char *s1__ign, const char *s2__ign, size_t len)
{
return __bpf_strncasecmp(s1__ign, s2__ign, true, len);
}
/**
@@ -4526,6 +4545,7 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE)
BTF_ID_FLAGS(func, __bpf_trap)
BTF_ID_FLAGS(func, bpf_strcmp);
BTF_ID_FLAGS(func, bpf_strcasecmp);
BTF_ID_FLAGS(func, bpf_strncasecmp);
BTF_ID_FLAGS(func, bpf_strchr);
BTF_ID_FLAGS(func, bpf_strchrnul);
BTF_ID_FLAGS(func, bpf_strnchr);

1
tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
View File

@@ -9,6 +9,7 @@
static const char * const test_cases[] = {
"strcmp",
"strcasecmp",
"strncasecmp",
"strchr",
"strchrnul",
"strnchr",

6
tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
View File

@@ -33,6 +33,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_null1(void *ctx) { return
SEC("syscall") __retval(USER_PTR_ERR)int test_strcmp_null2(void *ctx) { return bpf_strcmp("hello", NULL); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_null1(void *ctx) { return bpf_strcasecmp(NULL, "HELLO"); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strcasecmp_null2(void *ctx) { return bpf_strcasecmp("HELLO", NULL); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null1(void *ctx) { return bpf_strncasecmp(NULL, "HELLO", 5); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null2(void *ctx) { return bpf_strncasecmp("HELLO", NULL, 5); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strchr_null(void *ctx) { return bpf_strchr(NULL, 'a'); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strchrnul_null(void *ctx) { return bpf_strchrnul(NULL, 'a'); }
SEC("syscall") __retval(USER_PTR_ERR)int test_strnchr_null(void *ctx) { return bpf_strnchr(NULL, 1, 'a'); }
@@ -57,6 +59,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr1(void *ctx) { ret
SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr2(void *ctx) { return bpf_strcmp("hello", user_ptr); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr1(void *ctx) { return bpf_strcasecmp(user_ptr, "HELLO"); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr2(void *ctx) { return bpf_strcasecmp("HELLO", user_ptr); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr1(void *ctx) { return bpf_strncasecmp(user_ptr, "HELLO", 5); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr2(void *ctx) { return bpf_strncasecmp("HELLO", user_ptr, 5); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strchr_user_ptr(void *ctx) { return bpf_strchr(user_ptr, 'a'); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strchrnul_user_ptr(void *ctx) { return bpf_strchrnul(user_ptr, 'a'); }
SEC("syscall") __retval(USER_PTR_ERR) int test_strnchr_user_ptr(void *ctx) { return bpf_strnchr(user_ptr, 1, 'a'); }
@@ -83,6 +87,8 @@ SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault1(void *ctx) { return
SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault2(void *ctx) { return bpf_strcmp("hello", invalid_kern_ptr); }
SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault1(void *ctx) { return bpf_strcasecmp(invalid_kern_ptr, "HELLO"); }
SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault2(void *ctx) { return bpf_strcasecmp("HELLO", invalid_kern_ptr); }
SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault1(void *ctx) { return bpf_strncasecmp(invalid_kern_ptr, "HELLO", 5); }
SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault2(void *ctx) { return bpf_strncasecmp("HELLO", invalid_kern_ptr, 5); }
SEC("syscall") __retval(-EFAULT) int test_strchr_pagefault(void *ctx) { return bpf_strchr(invalid_kern_ptr, 'a'); }
SEC("syscall") __retval(-EFAULT) int test_strchrnul_pagefault(void *ctx) { return bpf_strchrnul(invalid_kern_ptr, 'a'); }
SEC("syscall") __retval(-EFAULT) int test_strnchr_pagefault(void *ctx) { return bpf_strnchr(invalid_kern_ptr, 1, 'a'); }

1
tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
View File

@@ -8,6 +8,7 @@ char long_str[XATTR_SIZE_MAX + 1];
SEC("syscall") int test_strcmp_too_long(void *ctx) { return bpf_strcmp(long_str, long_str); }
SEC("syscall") int test_strcasecmp_too_long(void *ctx) { return bpf_strcasecmp(long_str, long_str); }
SEC("syscall") int test_strncasecmp_too_long(void *ctx) { return bpf_strncasecmp(long_str, long_str, sizeof(long_str)); }
SEC("syscall") int test_strchr_too_long(void *ctx) { return bpf_strchr(long_str, 'b'); }
SEC("syscall") int test_strchrnul_too_long(void *ctx) { return bpf_strchrnul(long_str, 'b'); }
SEC("syscall") int test_strnchr_too_long(void *ctx) { return bpf_strnchr(long_str, sizeof(long_str), 'b'); }

7
tools/testing/selftests/bpf/progs/string_kfuncs_success.c
View File

@@ -17,6 +17,13 @@ __test(0) int test_strcasecmp_eq2(void *ctx) { return bpf_strcasecmp(str, "HELLO
__test(0) int test_strcasecmp_eq3(void *ctx) { return bpf_strcasecmp(str, "HELLO world"); }
__test(1) int test_strcasecmp_neq1(void *ctx) { return bpf_strcasecmp(str, "hello"); }
__test(1) int test_strcasecmp_neq2(void *ctx) { return bpf_strcasecmp(str, "HELLO"); }
__test(0) int test_strncasecmp_eq1(void *ctx) { return bpf_strncasecmp(str, "hello world", 11); }
__test(0) int test_strncasecmp_eq2(void *ctx) { return bpf_strncasecmp(str, "HELLO WORLD", 11); }
__test(0) int test_strncasecmp_eq3(void *ctx) { return bpf_strncasecmp(str, "HELLO world", 11); }
__test(0) int test_strncasecmp_eq4(void *ctx) { return bpf_strncasecmp(str, "hello", 5); }
__test(0) int test_strncasecmp_eq5(void *ctx) { return bpf_strncasecmp(str, "hello world!", 11); }
__test(-1) int test_strncasecmp_neq1(void *ctx) { return bpf_strncasecmp(str, "hello!", 6); }
__test(1) int test_strncasecmp_neq2(void *ctx) { return bpf_strncasecmp(str, "abc", 3); }
__test(1) int test_strchr_found(void *ctx) { return bpf_strchr(str, 'e'); }
__test(11) int test_strchr_null(void *ctx) { return bpf_strchr(str, '\0'); }
__test(-ENOENT) int test_strchr_notfound(void *ctx) { return bpf_strchr(str, 'x'); }