From 26bffaf6784a1c8deb25776be8924a7c3407b7bd Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Mon, 17 Oct 2022 17:06:39 +0200
Subject: [PATCH] ovl: remove privs in ovl_fallocate()
[ Upstream commit 23a8ce16419a3066829ad4a8b7032a75817af65b ]
Underlying fs doesn't remove privs because fallocate is called with
privileged mounter credentials.
This fixes some failure in fstests generic/683..687.
Fixes: aab8848cee5e ("ovl: add ovl_fallocate()")
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/overlayfs/file.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index b56e1f7a8c62b..28cb05ef018c7 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -516,9 +516,16 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
const struct cred *old_cred;
int ret;
+ inode_lock(inode);
+ /* Update mode */
+ ovl_copyattr(inode);
+ ret = file_remove_privs(file);
+ if (ret)
+ goto out_unlock;
+
ret = ovl_real_fdget(file, &real);
if (ret)
- return ret;
+ goto out_unlock;
old_cred = ovl_override_creds(file_inode(file)->i_sb);
ret = vfs_fallocate(real.file, mode, offset, len);
@@ -529,6 +536,9 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
fdput(real);
+out_unlock:
+ inode_unlock(inode);
+
return ret;
}
--
2.30.2