diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/seccomp.h | 6 | ||||
| -rw-r--r-- | include/uapi/linux/seccomp.h | 29 |
2 files changed, 32 insertions, 3 deletions
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 84868d37b35d..03583b6d1416 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -33,10 +33,10 @@ struct seccomp { #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER extern int __secure_computing(const struct seccomp_data *sd); -static inline int secure_computing(const struct seccomp_data *sd) +static inline int secure_computing(void) { if (unlikely(test_thread_flag(TIF_SECCOMP))) - return __secure_computing(sd); + return __secure_computing(NULL); return 0; } #else @@ -59,7 +59,7 @@ struct seccomp { }; struct seccomp_filter { }; #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER -static inline int secure_computing(struct seccomp_data *sd) { return 0; } +static inline int secure_computing(void) { return 0; } #else static inline void secure_computing_strict(int this_syscall) { return; } #endif diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h index 90734aa5aa36..be84d87f1f46 100644 --- a/include/uapi/linux/seccomp.h +++ b/include/uapi/linux/seccomp.h @@ -76,6 +76,35 @@ struct seccomp_notif { struct seccomp_data data; }; +/* + * Valid flags for struct seccomp_notif_resp + * + * Note, the SECCOMP_USER_NOTIF_FLAG_CONTINUE flag must be used with caution! + * If set by the process supervising the syscalls of another process the + * syscall will continue. This is problematic because of an inherent TOCTOU. + * An attacker can exploit the time while the supervised process is waiting on + * a response from the supervising process to rewrite syscall arguments which + * are passed as pointers of the intercepted syscall. + * It should be absolutely clear that this means that the seccomp notifier + * _cannot_ be used to implement a security policy! It should only ever be used + * in scenarios where a more privileged process supervises the syscalls of a + * lesser privileged process to get around kernel-enforced security + * restrictions when the privileged process deems this safe. In other words, + * in order to continue a syscall the supervising process should be sure that + * another security mechanism or the kernel itself will sufficiently block + * syscalls if arguments are rewritten to something unsafe. + * + * Similar precautions should be applied when stacking SECCOMP_RET_USER_NOTIF + * or SECCOMP_RET_TRACE. For SECCOMP_RET_USER_NOTIF filters acting on the + * same syscall, the most recently added filter takes precedence. This means + * that the new SECCOMP_RET_USER_NOTIF filter can override any + * SECCOMP_IOCTL_NOTIF_SEND from earlier filters, essentially allowing all + * such filtered syscalls to be executed by sending the response + * SECCOMP_USER_NOTIF_FLAG_CONTINUE. Note that SECCOMP_RET_TRACE can equally + * be overriden by SECCOMP_USER_NOTIF_FLAG_CONTINUE. + */ +#define SECCOMP_USER_NOTIF_FLAG_CONTINUE (1UL << 0) + struct seccomp_notif_resp { __u64 id; __s64 val; |