From: Miklos Szeredi <miklos@szeredi.hu>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-unionfs@vger.kernel.org
Subject: [PATCH 2/2] ovl: ignore permissions on underlying lookup
Date: Tue, 22 Mar 2016 14:23:02 +0100 [thread overview]
Message-ID: <20160322132302.GE11906@tucsk> (raw)
In-Reply-To: <20160322132103.GD11906@tucsk>
Generally permission checking is not necessary when overlayfs looks up a
dentry on one of the underlying layers, since search permission on base
directory was already checked in ovl_permission().
More specifically using lookup_one_len() causes a problem when the lower
directory lacks search permission for a specific user while the upper
directory does have search permission. Since lookups are cached, this
causes inconsistency in behavior: success depends on who did the first
lookup.
So instead use lookup_hash() which doesn't do the permission check.
Reported-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/overlayfs/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -379,7 +379,7 @@ static inline struct dentry *ovl_lookup_
struct dentry *dentry;
inode_lock(dir->d_inode);
- dentry = lookup_one_len(name->name, dir, name->len);
+ dentry = lookup_hash(name, dir, 0);
inode_unlock(dir->d_inode);
if (IS_ERR(dentry)) {
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
WARNING: multiple messages have this Message-ID (diff)
From: Miklos Szeredi <miklos@szeredi.hu>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-unionfs@vger.kernel.org
Subject: [PATCH 2/2] ovl: ignore permissions on underlying lookup
Date: Tue, 22 Mar 2016 14:23:02 +0100 [thread overview]
Message-ID: <20160322132302.GE11906@tucsk> (raw)
In-Reply-To: <20160322132103.GD11906@tucsk>
Generally permission checking is not necessary when overlayfs looks up a
dentry on one of the underlying layers, since search permission on base
directory was already checked in ovl_permission().
More specifically using lookup_one_len() causes a problem when the lower
directory lacks search permission for a specific user while the upper
directory does have search permission. Since lookups are cached, this
causes inconsistency in behavior: success depends on who did the first
lookup.
So instead use lookup_hash() which doesn't do the permission check.
Reported-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/overlayfs/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -379,7 +379,7 @@ static inline struct dentry *ovl_lookup_
struct dentry *dentry;
inode_lock(dir->d_inode);
- dentry = lookup_one_len(name->name, dir, name->len);
+ dentry = lookup_hash(name, dir, 0);
inode_unlock(dir->d_inode);
if (IS_ERR(dentry)) {
next prev parent reply other threads:[~2016-03-22 13:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-22 13:21 [PATCH 1/2] vfs: export lookup_hash() to modules Miklos Szeredi
2016-03-22 13:23 ` Miklos Szeredi [this message]
2016-03-22 13:23 ` [PATCH 2/2] ovl: ignore permissions on underlying lookup Miklos Szeredi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160322132302.GE11906@tucsk \
--to=miklos@szeredi.hu \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-unionfs@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.