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Subject[PATCH] ovl: avoid setting uninitialized creds
Date
If the call to ovl_copy_up() fails, we now call revert_creds on
an uninitialized structure after a recent patch, as found
by "gcc -Wmayby-uninitialized":

fs/overlayfs/inode.c: In function 'ovl_open_maybe_copy_up':
fs/overlayfs/inode.c:39:2: error: 'old_cred' may be used uninitialized in this function [-Werror=maybe-uninitialized]
fs/overlayfs/inode.c:22:21: note: 'old_cred' was declared here

This changes the code back to not call revert_creds unless
we have already called ovl_override_creds().

Fixes: 54249cd03956 ("ovl: during copy up, switch to mounter's creds early")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/overlayfs/inode.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index af87c7c109b7..65375f9c5563 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -30,13 +30,14 @@ static int ovl_copy_up_truncate(struct dentry *dentry)
old_cred = ovl_override_creds(dentry->d_sb);
err = vfs_getattr(&lowerpath, &stat);
if (err)
- goto out_dput_parent;
+ goto out_revert;

stat.size = 0;
err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);

-out_dput_parent:
+out_revert:
revert_creds(old_cred);
+out_dput_parent:
dput(parent);
return err;
}
--
2.9.0
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