On 3/6/24 2:00 AM, Kees Cook wrote:
On Tue, Mar 05, 2024 at 07:20:27PM +0500, Muhammad Usama Anjum wrote:
Hello,
I've been running execveat (execveat.c) locally on v6.1 and next-20240228. It has flaky test case. There are some test cases which fail consistently. The comment (not very clear) on top of failing cases is as following:
/*
- Execute as a long pathname relative to "/". If this is a script,
- the interpreter will launch but fail to open the script because its
- name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
- The failure code is usually 127 (POSIX: "If a command is not found,
- the exit status shall be 127."), but some systems give 126 (POSIX:
- "If the command name is found, but it is not an executable utility,
- the exit status shall be 126."), so allow either.
*/ The file name is just less than PATH_MAX (4096) and we are expecting the execveat() to fail with particular 99 or 127/128 error code. But kernel is returning 1 error code. Snippet from full output:
# child 3493092 exited with 1 not 99 nor 99 # child 3493094 exited with 1 not 127 nor 126
I'm not sure if test is wrong or the kernel has changed the return error codes.
The error code is actually coming from the script interpreter (in this case, "/bin/sh"). On my system, /bin/sh is /bin/dash, and I see the failure. If I manually change "script" to use "#!/bin/bash", the test passes for me.
Since lots of other selftests appears to depend on /bin/bash, I think the right fix is simply:
diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c index bf79d664c8e6..0546ca24f2b2 100644 --- a/tools/testing/selftests/exec/execveat.c +++ b/tools/testing/selftests/exec/execveat.c @@ -393,7 +393,7 @@ static int run_tests(void) static void prerequisites(void) { int fd;
- const char *script = "#!/bin/sh\nexit $*\n";
- const char *script = "#!/bin/bash\nexit $*\n";
/* Create ephemeral copies of files */ exe_cp("execveat", "execveat.ephemeral");
Can you test this and let me know if this fixes it for you?
I've tested this patch. Still getting same failures.
Thanks for the report!
-Kees