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?
Thanks for the report!
-Kees
--
Kees Cook
