diff options
| author | Kees Cook <keescook@chromium.org> | 2022-02-07 20:21:13 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-16 12:52:53 +0100 |
| commit | 1e30073c0e556410f853bc8686c638e58e0b2182 (patch) | |
| tree | 83ad8877a1fb54a4d95bda6dca9ce7020b2da938 /kernel | |
| parent | a3769078c9459ad373fc3a46b26b90016c6d50ac (diff) | |
seccomp: Invalidate seccomp mode to catch death failures
commit 495ac3069a6235bfdf516812a2a9b256671bbdf9 upstream.
If seccomp tries to kill a process, it should never see that process
again. To enforce this proactively, switch the mode to something
impossible. If encountered: WARN, reject all syscalls, and attempt to
kill the process again even harder.
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Fixes: 8112c4f140fa ("seccomp: remove 2-phase API")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/seccomp.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 1d62fa2b6b91..b2e1981663b8 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -28,6 +28,9 @@ #include <linux/syscalls.h> #include <linux/sysctl.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 @@ -706,6 +709,7 @@ static void __secure_computing_strict(int this_syscall) #ifdef SECCOMP_DEBUG dump_stack(); #endif + current->seccomp.mode = SECCOMP_MODE_DEAD; seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true); do_exit(SIGKILL); } @@ -892,6 +896,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd, case SECCOMP_RET_KILL_THREAD: case SECCOMP_RET_KILL_PROCESS: default: + current->seccomp.mode = SECCOMP_MODE_DEAD; seccomp_log(this_syscall, SIGSYS, action, true); /* Dump core only if this is the last remaining thread. */ if (action == SECCOMP_RET_KILL_PROCESS || @@ -944,6 +949,11 @@ int __secure_computing(const struct seccomp_data *sd) return 0; case SECCOMP_MODE_FILTER: return __seccomp_filter(this_syscall, sd, false); + /* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */ + case SECCOMP_MODE_DEAD: + WARN_ON_ONCE(1); + do_exit(SIGKILL); + return -1; default: BUG(); } |