| Message ID | 20250128150307.GA15325@redhat.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | [v2,1/4] seccomp/mips: change syscall_trace_enter() to use secure_computing() | expand |
On Tue, Jan 28, 2025 at 4:03 PM Oleg Nesterov <oleg@redhat.com> wrote: > Depending on CONFIG_HAVE_ARCH_SECCOMP_FILTER, __secure_computing(NULL) > will crash or not. This is not consistent/safe, especially considering > that after the previous change __secure_computing(sd) is always called > with sd == NULL. > > Fortunately, if CONFIG_HAVE_ARCH_SECCOMP_FILTER=n, __secure_computing() > has no callers, these architectures use secure_computing_strict(). Yet > it make sense make __secure_computing(NULL) safe in this case. > > Note also that with this change we can unexport secure_computing_strict() > and change the current callers to use __secure_computing(NULL). > > Fixes: 8cf8dfceebda ("seccomp: Stub for !HAVE_ARCH_SECCOMP_FILTER") > Signed-off-by: Oleg Nesterov <oleg@redhat.com> I had no idea it was this complex, thanks a lot for looking into this Oleg! Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Yours, Linus Walleij
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index e45531455d3b..d55949071c30 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -22,8 +22,9 @@ #include <linux/atomic.h> #include <asm/seccomp.h> -#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER extern int __secure_computing(const struct seccomp_data *sd); + +#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER static inline int secure_computing(void) { if (unlikely(test_syscall_work(SECCOMP))) @@ -32,11 +33,6 @@ static inline int secure_computing(void) } #else extern void secure_computing_strict(int this_syscall); -static inline int __secure_computing(const struct seccomp_data *sd) -{ - secure_computing_strict(sd->nr); - return 0; -} #endif extern long prctl_get_seccomp(void); diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 385d48293a5f..327b7b486f1c 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -29,13 +29,11 @@ #include <linux/syscalls.h> #include <linux/sysctl.h> +#include <asm/syscall.h> + /* Not exposed in headers: strictly internal use only. */ #define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1) -#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER -#include <asm/syscall.h> -#endif - #ifdef CONFIG_SECCOMP_FILTER #include <linux/file.h> #include <linux/filter.h> @@ -1062,6 +1060,14 @@ void secure_computing_strict(int this_syscall) else BUG(); } +int __secure_computing(const struct seccomp_data *sd) +{ + int this_syscall = sd ? sd->nr : + syscall_get_nr(current, current_pt_regs()); + + secure_computing_strict(this_syscall); + return 0; +} #else #ifdef CONFIG_SECCOMP_FILTER
Depending on CONFIG_HAVE_ARCH_SECCOMP_FILTER, __secure_computing(NULL) will crash or not. This is not consistent/safe, especially considering that after the previous change __secure_computing(sd) is always called with sd == NULL. Fortunately, if CONFIG_HAVE_ARCH_SECCOMP_FILTER=n, __secure_computing() has no callers, these architectures use secure_computing_strict(). Yet it make sense make __secure_computing(NULL) safe in this case. Note also that with this change we can unexport secure_computing_strict() and change the current callers to use __secure_computing(NULL). Fixes: 8cf8dfceebda ("seccomp: Stub for !HAVE_ARCH_SECCOMP_FILTER") Signed-off-by: Oleg Nesterov <oleg@redhat.com> --- include/linux/seccomp.h | 8 ++------ kernel/seccomp.c | 14 ++++++++++---- 2 files changed, 12 insertions(+), 10 deletions(-)