[PATCH] exec: Fix min/max typo in stack space calculation

[Kees Cook]

When handling the argc == 0 case, the stack space calculation should be
using max() not min().

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
This is a fix for exec-force-single-empty-string-when-argv-is-empty.patch
https://lore.kernel.org/mm-commits/20220201004100.BF6D6C340E8@xxxxxxxxxxxxxxx/
---
 fs/exec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/exec.c b/fs/exec.c
index bbf3aadf7ce1..40b1008fb0f7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -502,7 +502,7 @@ static int bprm_stack_limits(struct linux_binprm *bprm)
 	 * argc can never be 0, to keep them from walking envp by accident.
 	 * See do_execveat_common().
 	 */
-	ptr_size = (min(bprm->argc, 1) + bprm->envc) * sizeof(void *);
+	ptr_size = (max(bprm->argc, 1) + bprm->envc) * sizeof(void *);
 	if (limit <= ptr_size)
 		return -E2BIG;
 	limit -= ptr_size;
-- 
2.30.2