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[PATCH 1/3] xfs: validate acl count

To: stable@xxxxxxxxxxxxxxx
Subject: [PATCH 1/3] xfs: validate acl count
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Tue, 6 Dec 2011 16:21:05 -0500
Cc: xfs@xxxxxxxxxxx
In-reply-to: <20111206212056.GA24640@xxxxxxxxxxxxx>
References: <20111206212056.GA24640@xxxxxxxxxxxxx>
User-agent: Mutt/1.5.21 (2010-09-15)
commit fa8b18edd752a8b4e9d1ee2cd615b82c93cf8bba upstream.

This prevents in-memory corruption and possible panics if the on-disk
ACL is badly corrupted.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Ben Myers <bpm@xxxxxxx>
---
 fs/xfs/linux-2.6/xfs_acl.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index 39f4f80..4b9fb91 100644
--- a/fs/xfs/linux-2.6/xfs_acl.c
+++ b/fs/xfs/linux-2.6/xfs_acl.c
@@ -42,6 +42,8 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
        int count, i;
 
        count = be32_to_cpu(aclp->acl_cnt);
+       if (count > XFS_ACL_MAX_ENTRIES)
+               return ERR_PTR(-EFSCORRUPTED);
 
        acl = posix_acl_alloc(count, GFP_KERNEL);
        if (!acl)
-- 
1.7.7.3

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