diff options
| author | Viktor Malik <vmalik@redhat.com> | 2026-03-09 12:23:57 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-03-09 09:28:42 -0700 |
| commit | 20c2e102a2f30e7e47cba9816ab226de296e8e57 (patch) | |
| tree | 6347001190568aa929dbf55092e08896e06cb4b6 /kernel | |
| parent | 16d9c5660692d6f0e6aba367274de2b6dfd4343c (diff) | |
bpf: Always allow fmod_ret programs on syscalls
fmod_ret BPF programs can only be attached to selected functions. For
convenience, the error injection list was originally used (along with
functions prefixed with "security_"), which contains syscalls and
several other functions.
When error injection is disabled (CONFIG_FUNCTION_ERROR_INJECTION=n),
that list is empty and fmod_ret programs are effectively unavailable for
most of the functions. In such a case, at least enable fmod_ret programs
on syscalls.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/472310f9a5f4944ad03214e4d943a4830fd8eb76.1773055375.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a52e57f3eb80..8e4f69918693 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -24952,15 +24952,6 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) } #define SECURITY_PREFIX "security_" -static int check_attach_modify_return(unsigned long addr, const char *func_name) -{ - if (within_error_injection_list(addr) || - !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1)) - return 0; - - return -EINVAL; -} - #ifdef CONFIG_FUNCTION_ERROR_INJECTION /* list of non-sleepable functions that are otherwise on @@ -24996,6 +24987,15 @@ static int check_attach_sleepable(u32 btf_id, unsigned long addr, const char *fu return -EINVAL; } +static int check_attach_modify_return(unsigned long addr, const char *func_name) +{ + if (within_error_injection_list(addr) || + !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1)) + return 0; + + return -EINVAL; +} + #else /* Unfortunately, the arch-specific prefixes are hard-coded in arch syscall code @@ -25023,7 +25023,7 @@ static bool has_arch_syscall_prefix(const char *func_name) #endif } -/* Without error injection, allow sleepable progs on syscalls. */ +/* Without error injection, allow sleepable and fmod_ret progs on syscalls. */ static int check_attach_sleepable(u32 btf_id, unsigned long addr, const char *func_name) { @@ -25033,6 +25033,15 @@ static int check_attach_sleepable(u32 btf_id, unsigned long addr, const char *fu return -EINVAL; } +static int check_attach_modify_return(unsigned long addr, const char *func_name) +{ + if (has_arch_syscall_prefix(func_name) || + !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1)) + return 0; + + return -EINVAL; +} + #endif /* CONFIG_FUNCTION_ERROR_INJECTION */ int bpf_check_attach_target(struct bpf_verifier_log *log, |