Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'bpf-add-kfunc-bpf_strncasecmp'
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>
+40
-5
+25
-5
kernel/bpf/helpers.c
+25
-5
kernel/bpf/helpers.c
···
3413
3413
* __get_kernel_nofault instead of plain dereference to make them safe.
3414
3414
*/
3415
3415
3416
-
static int __bpf_strcasecmp(const char *s1, const char *s2, bool ignore_case)
3416
+
static int __bpf_strncasecmp(const char *s1, const char *s2, bool ignore_case, size_t len)
3417
3417
{
3418
3418
char c1, c2;
3419
3419
int i;
···
3424
3424
}
3425
3425
3426
3426
guard(pagefault)();
3427
-
for (i = 0; i < XATTR_SIZE_MAX; i++) {
3427
+
for (i = 0; i < len && i < XATTR_SIZE_MAX; i++) {
3428
3428
__get_kernel_nofault(&c1, s1, char, err_out);
3429
3429
__get_kernel_nofault(&c2, s2, char, err_out);
3430
3430
if (ignore_case) {
···
3438
3438
s1++;
3439
3439
s2++;
3440
3440
}
3441
-
return -E2BIG;
3441
+
return i == XATTR_SIZE_MAX ? -E2BIG : 0;
3442
3442
err_out:
3443
3443
return -EFAULT;
3444
3444
}
···
3458
3458
*/
3459
3459
__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
3460
3460
{
3461
-
return __bpf_strcasecmp(s1__ign, s2__ign, false);
3461
+
return __bpf_strncasecmp(s1__ign, s2__ign, false, XATTR_SIZE_MAX);
3462
3462
}
3463
3463
3464
3464
/**
···
3476
3476
*/
3477
3477
__bpf_kfunc int bpf_strcasecmp(const char *s1__ign, const char *s2__ign)
3478
3478
{
3479
-
return __bpf_strcasecmp(s1__ign, s2__ign, true);
3479
+
return __bpf_strncasecmp(s1__ign, s2__ign, true, XATTR_SIZE_MAX);
3480
+
}
3481
+
3482
+
/*
3483
+
* bpf_strncasecmp - Compare two length-limited strings, ignoring case
3484
+
* @s1__ign: One string
3485
+
* @s2__ign: Another string
3486
+
* @len: The maximum number of characters to compare
3487
+
*
3488
+
* Return:
3489
+
* * %0 - Strings are equal
3490
+
* * %-1 - @s1__ign is smaller
3491
+
* * %1 - @s2__ign is smaller
3492
+
* * %-EFAULT - Cannot read one of the strings
3493
+
* * %-E2BIG - One of strings is too large
3494
+
* * %-ERANGE - One of strings is outside of kernel address space
3495
+
*/
3496
+
__bpf_kfunc int bpf_strncasecmp(const char *s1__ign, const char *s2__ign, size_t len)
3497
+
{
3498
+
return __bpf_strncasecmp(s1__ign, s2__ign, true, len);
3480
3499
}
3481
3500
3482
3501
/**
···
4545
4526
BTF_ID_FLAGS(func, __bpf_trap)
4546
4527
BTF_ID_FLAGS(func, bpf_strcmp);
4547
4528
BTF_ID_FLAGS(func, bpf_strcasecmp);
4529
+
BTF_ID_FLAGS(func, bpf_strncasecmp);
4548
4530
BTF_ID_FLAGS(func, bpf_strchr);
4549
4531
BTF_ID_FLAGS(func, bpf_strchrnul);
4550
4532
BTF_ID_FLAGS(func, bpf_strnchr);
+1
tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
+1
tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
+6
tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
+6
tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
···
33
33
SEC("syscall") __retval(USER_PTR_ERR)int test_strcmp_null2(void *ctx) { return bpf_strcmp("hello", NULL); }
34
34
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_null1(void *ctx) { return bpf_strcasecmp(NULL, "HELLO"); }
35
35
SEC("syscall") __retval(USER_PTR_ERR)int test_strcasecmp_null2(void *ctx) { return bpf_strcasecmp("HELLO", NULL); }
36
+
SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null1(void *ctx) { return bpf_strncasecmp(NULL, "HELLO", 5); }
37
+
SEC("syscall") __retval(USER_PTR_ERR)int test_strncasecmp_null2(void *ctx) { return bpf_strncasecmp("HELLO", NULL, 5); }
36
38
SEC("syscall") __retval(USER_PTR_ERR)int test_strchr_null(void *ctx) { return bpf_strchr(NULL, 'a'); }
37
39
SEC("syscall") __retval(USER_PTR_ERR)int test_strchrnul_null(void *ctx) { return bpf_strchrnul(NULL, 'a'); }
38
40
SEC("syscall") __retval(USER_PTR_ERR)int test_strnchr_null(void *ctx) { return bpf_strnchr(NULL, 1, 'a'); }
···
59
57
SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr2(void *ctx) { return bpf_strcmp("hello", user_ptr); }
60
58
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr1(void *ctx) { return bpf_strcasecmp(user_ptr, "HELLO"); }
61
59
SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr2(void *ctx) { return bpf_strcasecmp("HELLO", user_ptr); }
60
+
SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr1(void *ctx) { return bpf_strncasecmp(user_ptr, "HELLO", 5); }
61
+
SEC("syscall") __retval(USER_PTR_ERR) int test_strncasecmp_user_ptr2(void *ctx) { return bpf_strncasecmp("HELLO", user_ptr, 5); }
62
62
SEC("syscall") __retval(USER_PTR_ERR) int test_strchr_user_ptr(void *ctx) { return bpf_strchr(user_ptr, 'a'); }
63
63
SEC("syscall") __retval(USER_PTR_ERR) int test_strchrnul_user_ptr(void *ctx) { return bpf_strchrnul(user_ptr, 'a'); }
64
64
SEC("syscall") __retval(USER_PTR_ERR) int test_strnchr_user_ptr(void *ctx) { return bpf_strnchr(user_ptr, 1, 'a'); }
···
87
83
SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault2(void *ctx) { return bpf_strcmp("hello", invalid_kern_ptr); }
88
84
SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault1(void *ctx) { return bpf_strcasecmp(invalid_kern_ptr, "HELLO"); }
89
85
SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault2(void *ctx) { return bpf_strcasecmp("HELLO", invalid_kern_ptr); }
86
+
SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault1(void *ctx) { return bpf_strncasecmp(invalid_kern_ptr, "HELLO", 5); }
87
+
SEC("syscall") __retval(-EFAULT) int test_strncasecmp_pagefault2(void *ctx) { return bpf_strncasecmp("HELLO", invalid_kern_ptr, 5); }
90
88
SEC("syscall") __retval(-EFAULT) int test_strchr_pagefault(void *ctx) { return bpf_strchr(invalid_kern_ptr, 'a'); }
91
89
SEC("syscall") __retval(-EFAULT) int test_strchrnul_pagefault(void *ctx) { return bpf_strchrnul(invalid_kern_ptr, 'a'); }
92
90
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
+1
tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
···
8
8
9
9
SEC("syscall") int test_strcmp_too_long(void *ctx) { return bpf_strcmp(long_str, long_str); }
10
10
SEC("syscall") int test_strcasecmp_too_long(void *ctx) { return bpf_strcasecmp(long_str, long_str); }
11
+
SEC("syscall") int test_strncasecmp_too_long(void *ctx) { return bpf_strncasecmp(long_str, long_str, sizeof(long_str)); }
11
12
SEC("syscall") int test_strchr_too_long(void *ctx) { return bpf_strchr(long_str, 'b'); }
12
13
SEC("syscall") int test_strchrnul_too_long(void *ctx) { return bpf_strchrnul(long_str, 'b'); }
13
14
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
+7
tools/testing/selftests/bpf/progs/string_kfuncs_success.c
···
17
17
__test(0) int test_strcasecmp_eq3(void *ctx) { return bpf_strcasecmp(str, "HELLO world"); }
18
18
__test(1) int test_strcasecmp_neq1(void *ctx) { return bpf_strcasecmp(str, "hello"); }
19
19
__test(1) int test_strcasecmp_neq2(void *ctx) { return bpf_strcasecmp(str, "HELLO"); }
20
+
__test(0) int test_strncasecmp_eq1(void *ctx) { return bpf_strncasecmp(str, "hello world", 11); }
21
+
__test(0) int test_strncasecmp_eq2(void *ctx) { return bpf_strncasecmp(str, "HELLO WORLD", 11); }
22
+
__test(0) int test_strncasecmp_eq3(void *ctx) { return bpf_strncasecmp(str, "HELLO world", 11); }
23
+
__test(0) int test_strncasecmp_eq4(void *ctx) { return bpf_strncasecmp(str, "hello", 5); }
24
+
__test(0) int test_strncasecmp_eq5(void *ctx) { return bpf_strncasecmp(str, "hello world!", 11); }
25
+
__test(-1) int test_strncasecmp_neq1(void *ctx) { return bpf_strncasecmp(str, "hello!", 6); }
26
+
__test(1) int test_strncasecmp_neq2(void *ctx) { return bpf_strncasecmp(str, "abc", 3); }
20
27
__test(1) int test_strchr_found(void *ctx) { return bpf_strchr(str, 'e'); }
21
28
__test(11) int test_strchr_null(void *ctx) { return bpf_strchr(str, '\0'); }
22
29
__test(-ENOENT) int test_strchr_notfound(void *ctx) { return bpf_strchr(str, 'x'); }