If get_unused_fd_flags() fails, the error handling is incomplete
because bprm->cred is already set to NULL, and therefore
free_bprm will not unlock the cred_guard_mutex.
Note there are two error conditions which end up here,
one before and one after bprm->cred is cleared.
Fixes: b8a61c9e7b4a ("exec: Generic execfd support")
Signed-off-by: Bernd Edlinger <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
---
fs/exec.c | 3 +++
1 file changed, 3 insertions(+)
v2: rebased to v6.7, retested and updated the commit message
to fix a checkpatch.pl style nit about the too short sha1 hash
in the Fixes: statement.
And retained Eric's Acked-by from:
https://lore.kernel.org/lkml/87mts2kcrm.fsf@disp2133/
Thanks
Bernd.
diff --git a/fs/exec.c b/fs/exec.c
index 4aa19b24f281..6d9ed2d765ef 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1408,6 +1408,9 @@ int begin_new_exec(struct linux_binprm * bprm)
out_unlock:
up_write(&me->signal->exec_update_lock);
+ if (!bprm->cred)
+ mutex_unlock(&me->signal->cred_guard_mutex);
+
out:
return retval;
}
--
2.39.2
If get_unused_fd_flags() fails, the error handling is incomplete
because bprm->cred is already set to NULL, and therefore
free_bprm will not unlock the cred_guard_mutex.
Note there are two error conditions which end up here,
one before and one after bprm->cred is cleared.
Fixes: b8a61c9e7b4a ("exec: Generic execfd support")
Signed-off-by: Bernd Edlinger <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
---
fs/exec.c | 3 +++
1 file changed, 3 insertions(+)
v2: rebased to v6.7, retested and updated the commit message
to fix a checkpatch.pl style nit about the too short sha1 hash
in the Fixes: statement.
And retained Eric's Acked-by from:
https://lore.kernel.org/lkml/87mts2kcrm.fsf@disp2133/
v3: removed empty lines after Fixes: and Signed-off-by: header.
Thanks
Bernd.
diff --git a/fs/exec.c b/fs/exec.c
index 8cdd5b2dd09c..e88249a1ce07 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1409,6 +1409,9 @@ int begin_new_exec(struct linux_binprm * bprm)
out_unlock:
up_write(&me->signal->exec_update_lock);
+ if (!bprm->cred)
+ mutex_unlock(&me->signal->cred_guard_mutex);
+
out:
return retval;
}
--
2.39.2
On Mon, 22 Jan 2024 19:34:21 +0100, Bernd Edlinger wrote:
> If get_unused_fd_flags() fails, the error handling is incomplete
> because bprm->cred is already set to NULL, and therefore
> free_bprm will not unlock the cred_guard_mutex.
> Note there are two error conditions which end up here,
> one before and one after bprm->cred is cleared.
>
>
> [...]
Applied to for-next/execve, thanks!
[1/1] Fix error handling in begin_new_exec
https://git.kernel.org/kees/c/84c39ec57d40
Take care,
--
Kees Cook