linux-ext4 - [PATCH] off-by-one in "Add checks to validate extent entries."

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Message-ID: <49D4F217.7050105@ph.tum.de>
Date:	Thu, 02 Apr 2009 19:12:55 +0200
From:	Thiemo Nagel <thiemo.nagel@...tum.de>
To:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	Theodore Tso <tytso@....edu>
CC:	linux-ext4@...r.kernel.org
Subject: [PATCH] off-by-one in "Add checks to validate extent entries."

Theodore Tso wrote:
 > I haven't had time yet to check your other patches; could you also
 > take a quick scan to make sure we have all of the byte-swapping calls
 > needed for proper big-endian checking, that we're using the correct
 > __le32 types and not doing any casts?

I had a look at all patches I have sent, but I didn't notice anything 
suspicious.  While doing that, however I think I found an off-by-one in
56b19868aca856a7d7bf20c3a7a1030e4fd75b2b

Kind regards,

Thiemo

---
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ac77d8b..6132353 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -342,7 +342,7 @@ static int ext4_valid_extent_idx(struct inode *inode,
         ext4_fsblk_t block = idx_pblock(ext_idx);
         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
         if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
-                       (block > ext4_blocks_count(es))))
+                       (block >= ext4_blocks_count(es))))
                 return 0;
         else
                 return 1;
--
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