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From fbf6404575f42b383d9607321bd129f0e28fc0d7 Mon Sep 17 00:00:00 2001
From: Carlos Maiolino <cmaiolino@redhat.com>
Date: Tue, 18 Oct 2011 02:18:58 -0200
Subject: [PATCH] Fix possible memory corruption in xfs_readlink

Fixes a possible memory corruption when the link is larger than
MAXPATHLEN and XFS_DEBUG is not enabled. This also remove the
S_ISLNK assert, since the inode mode is checked previously in
xfs_readlink_by_handle() and via VFS.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 fs/xfs/xfs_vnodeops.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index c164683..529d983 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -564,13 +564,17 @@ xfs_readlink(
 
 	xfs_ilock(ip, XFS_ILOCK_SHARED);
 
-	ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFLNK);
-	ASSERT(ip->i_d.di_size <= MAXPATHLEN);
-
 	pathlen = ip->i_d.di_size;
 	if (!pathlen)
 		goto out;
 
+	if (pathlen > MAXPATHLEN) {
+		xfs_fs_cmn_err(CE_ALERT, mp, "%s: inode (%llu) symlink length (%d) too long",
+			 __func__, (unsigned long long)ip->i_ino, pathlen);
+		ASSERT(0);
+		return XFS_ERROR(EFSCORRUPTED);
+	}
+
 	if (ip->i_df.if_flags & XFS_IFINLINE) {
 		memcpy(link, ip->i_df.if_u1.if_data, pathlen);
 		link[pathlen] = '\0';
-- 
1.7.6.4