linux-kernel - [PATCH 19/21] Unionfs: Properly handle stale inodes passed to unionfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  9 Apr 2007 10:54:10 -0400
From:	"Josef 'Jeff' Sipek" <jsipek@...sunysb.edu>
To:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:	akpm@...ux-foundation.org, Erez Zadok <ezk@...sunysb.edu>,
	"Josef 'Jeff' Sipek" <jsipek@...sunysb.edu>
Subject: [PATCH 19/21] Unionfs: Properly handle stale inodes passed to unionfs_permission

From: Erez Zadok <ezk@...sunysb.edu>

Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@...sunysb.edu>
---
 fs/unionfs/inode.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
index edd226f..5c452b6 100644
--- a/fs/unionfs/inode.c
+++ b/fs/unionfs/inode.c
@@ -843,8 +843,21 @@ static int unionfs_permission(struct inode *inode, int mask,
 	const int is_file = !S_ISDIR(inode->i_mode);
 	const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
 
+	unionfs_read_lock(inode->i_sb);
+
 	bstart = ibstart(inode);
 	bend = ibend(inode);
+	if (bstart < 0 || bend < 0) {
+		/*
+		 * With branch-management, we can get a stale inode here.
+		 * If so, we return ESTALE back to link_path_walk, which
+		 * would discard the dcache entry and re-lookup the
+		 * dentry+inode.  This should be equivalent to issuing
+		 * __unionfs_d_revalidate_chain on nd.dentry here.
+		 */
+		err = -ESTALE;	/* force revalidate */
+		goto out;
+	}
 
 	for (bindex = bstart; bindex <= bend; bindex++) {
 		hidden_inode = unionfs_lower_inode_idx(inode, bindex);
@@ -881,6 +894,7 @@ static int unionfs_permission(struct inode *inode, int mask,
 	}
 
 out:
+	unionfs_read_unlock(inode->i_sb);
 	return err;
 }
 
-- 
1.5.0.3.268.g3dda

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/