[PATCH v19 4/4] overlayfs: inode_owner_or_capable called during execv

From: David Anderson
Date: Tue Nov 16 2021 - 20:58:57 EST

From: John Stultz <john.stultz@xxxxxxxxxx>

Using old_creds as an indication that we are not overriding the
credentials, bypass call to inode_owner_or_capable. This solves
a problem with all execv calls being blocked when using the caller's

Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
Signed-off-by: David Anderson <dvander@xxxxxxxxxx>
Fixes: 05acefb4872da ("ovl: check permission to open real file")
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: linux-unionfs@xxxxxxxxxxxxxxx
Cc: Stephen Smalley <sds@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
Cc: kernel-team@xxxxxxxxxxx
Cc: selinux@xxxxxxxxxxxxxxx
Cc: paulmoore@xxxxxxxxxxxxx
Cc: Luca.Boccassi@xxxxxxxxxxxxx

v19 - rebase

v18 - rebase

v17 - rebase

v16 - introduced fix over rebased series
fs/overlayfs/file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 11d8277c94cd..586de55bba79 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -55,7 +55,8 @@ static struct file *ovl_open_realfile(const struct file *file,
if (err) {
realfile = ERR_PTR(err);
} else {
- if (!inode_owner_or_capable(&init_user_ns, realinode))
+ if (old_cred && !inode_owner_or_capable(&init_user_ns,
+ realinode))
flags &= ~O_NOATIME;

realfile = open_with_fake_path(&file->f_path, flags, realinode,