diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2025-08-29 11:32:03 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-09-09 15:09:29 -0700 |
| commit | 813104c192740ca58ce7131faf31a7f118645ae1 (patch) | |
| tree | b28fb0d124e318582dbf9586f3de16535c41bb45 | |
| parent | 387be23a95b14705a804900c3a0db5a12bf19636 (diff) | |
| parent | 6624fb2f3382271953f951d46f2ea30415a0917e (diff) | |
Merge branch 'fix-bpf_strnstr-len-error'
Rong Tao says:
====================
Fix bpf_strnstr() wrong 'len' parameter, bpf_strnstr("open", "open", 4)
should return 0 instead of -ENOENT. And fix a more general case when s2
is a suffix of the first len characters of s1.
====================
Link: https://patch.msgid.link/tencent_E72A37AF03A3B18853066E421B5969976208@qq.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/helpers.c | 9 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/string_kfuncs_success.c | 8 |
2 files changed, 14 insertions, 3 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 6b4877e85a68..b9b0c5fe33f6 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3664,10 +3664,17 @@ __bpf_kfunc int bpf_strnstr(const char *s1__ign, const char *s2__ign, size_t len guard(pagefault)(); for (i = 0; i < XATTR_SIZE_MAX; i++) { - for (j = 0; i + j < len && j < XATTR_SIZE_MAX; j++) { + for (j = 0; i + j <= len && j < XATTR_SIZE_MAX; j++) { __get_kernel_nofault(&c2, s2__ign + j, char, err_out); if (c2 == '\0') return i; + /* + * We allow reading an extra byte from s2 (note the + * `i + j <= len` above) to cover the case when s2 is + * a suffix of the first len chars of s1. + */ + if (i + j == len) + break; __get_kernel_nofault(&c1, s1__ign + j, char, err_out); if (c1 == '\0') return -ENOENT; diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c index 46697f381878..a47690174e0e 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c @@ -30,8 +30,12 @@ __test(2) int test_strcspn(void *ctx) { return bpf_strcspn(str, "lo"); } __test(6) int test_strstr_found(void *ctx) { return bpf_strstr(str, "world"); } __test(-ENOENT) int test_strstr_notfound(void *ctx) { return bpf_strstr(str, "hi"); } __test(0) int test_strstr_empty(void *ctx) { return bpf_strstr(str, ""); } -__test(0) int test_strnstr_found(void *ctx) { return bpf_strnstr(str, "hello", 6); } -__test(-ENOENT) int test_strnstr_notfound(void *ctx) { return bpf_strnstr(str, "hi", 10); } +__test(0) int test_strnstr_found1(void *ctx) { return bpf_strnstr("", "", 0); } +__test(0) int test_strnstr_found2(void *ctx) { return bpf_strnstr(str, "hello", 5); } +__test(0) int test_strnstr_found3(void *ctx) { return bpf_strnstr(str, "hello", 6); } +__test(-ENOENT) int test_strnstr_notfound1(void *ctx) { return bpf_strnstr(str, "hi", 10); } +__test(-ENOENT) int test_strnstr_notfound2(void *ctx) { return bpf_strnstr(str, "hello", 4); } +__test(-ENOENT) int test_strnstr_notfound3(void *ctx) { return bpf_strnstr("", "a", 0); } __test(0) int test_strnstr_empty(void *ctx) { return bpf_strnstr(str, "", 1); } char _license[] SEC("license") = "GPL"; |