From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kees Cook" <keescook@chromium.org>,
"Robert Święcki" <robert@swiecki.net>,
"Andy Lutomirski" <luto@amacapital.net>,
"Will Drewry" <wad@chromium.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH 3/3] samples/seccomp: Adjust sample to also provide kill option
Date: Wed, 9 Feb 2022 18:53:21 -0800 [thread overview]
Message-ID: <20220210025321.787113-4-keescook@chromium.org> (raw)
In-Reply-To: <20220210025321.787113-1-keescook@chromium.org>
As a quick way to test SECCOMP_RET_KILL, have a negative errno mean to
kill the process.
While we're in here, also swap the arch and syscall arguments so they're
ordered more like how seccomp filters order them.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
samples/seccomp/dropper.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/samples/seccomp/dropper.c b/samples/seccomp/dropper.c
index cc0648eb389e..4bca4b70f665 100644
--- a/samples/seccomp/dropper.c
+++ b/samples/seccomp/dropper.c
@@ -25,7 +25,7 @@
#include <sys/prctl.h>
#include <unistd.h>
-static int install_filter(int nr, int arch, int error)
+static int install_filter(int arch, int nr, int error)
{
struct sock_filter filter[] = {
BPF_STMT(BPF_LD+BPF_W+BPF_ABS,
@@ -42,6 +42,10 @@ static int install_filter(int nr, int arch, int error)
.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
.filter = filter,
};
+ if (error == -1) {
+ struct sock_filter kill = BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL);
+ filter[4] = kill;
+ }
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
perror("prctl(NO_NEW_PRIVS)");
return 1;
@@ -57,9 +61,10 @@ int main(int argc, char **argv)
{
if (argc < 5) {
fprintf(stderr, "Usage:\n"
- "dropper <syscall_nr> <arch> <errno> <prog> [<args>]\n"
+ "dropper <arch> <syscall_nr> <errno> <prog> [<args>]\n"
"Hint: AUDIT_ARCH_I386: 0x%X\n"
" AUDIT_ARCH_X86_64: 0x%X\n"
+ " errno == -1 means SECCOMP_RET_KILL\n"
"\n", AUDIT_ARCH_I386, AUDIT_ARCH_X86_64);
return 1;
}
--
2.30.2
next prev parent reply other threads:[~2022-02-10 2:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 2:53 [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE Kees Cook
2022-02-10 2:53 ` [PATCH 1/3] " Kees Cook
2022-02-10 16:18 ` Jann Horn
2022-02-10 17:37 ` Kees Cook
2022-02-10 18:01 ` Jann Horn
2022-02-10 18:12 ` Eric W. Biederman
2022-02-10 21:09 ` Kees Cook
2022-02-11 20:15 ` Jann Horn
2022-02-10 18:16 ` Eric W. Biederman
2022-02-10 2:53 ` [PATCH 2/3] seccomp: Invalidate seccomp mode to catch death failures Kees Cook
2022-02-10 2:53 ` Kees Cook [this message]
2022-02-10 18:17 ` [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE Eric W. Biederman
2022-02-10 18:41 ` Kees Cook
2022-02-10 18:58 ` Eric W. Biederman
2022-02-10 20:43 ` Kees Cook
2022-02-10 22:48 ` Eric W. Biederman
2022-02-11 1:26 ` Kees Cook
2022-02-11 1:47 ` Eric W. Biederman
2022-02-11 2:53 ` Kees Cook
2022-02-11 12:54 ` Robert Święcki
2022-02-11 17:46 ` Eric W. Biederman
2022-02-11 18:57 ` Robert Święcki
2022-02-11 20:01 ` Kees Cook
2022-02-11 19:58 ` Kees Cook
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