Subject: [PATCH] Fix possible memory corruption in xfs_readlink From: Carlos Maiolino Date: Tue, 18 Oct 2011 02:18:58 -0200 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 --- fs/xfs/xfs_vnodeops.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index 51fc429..c3288be 100644 --- a/fs/xfs/xfs_vnodeops.c +++ b/fs/xfs/xfs_vnodeops.c @@ -123,13 +123,18 @@ xfs_readlink( xfs_ilock(ip, XFS_ILOCK_SHARED); - ASSERT(S_ISLNK(ip->i_d.di_mode)); - ASSERT(ip->i_d.di_size <= MAXPATHLEN); - pathlen = ip->i_d.di_size; if (!pathlen) goto out; + if (pathlen > MAXPATHLEN) { + xfs_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'; -- 1.7.6.2