[Xen-changelog] [qemu-xen-unstable] Improve block range checks

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

commit 8c20718dab7f1612dcc40fe478642cbc1102aa9b
Author: Kevin Wolf <kwolf@xxxxxxxxxx>
Date:   Fri May 8 14:47:24 2009 +0200

    Improve block range checks
    
    This patch makes the range checks for block requests more strict: It fixes a
    potential integer overflow and checks for negative offsets. Also, it adds 
the
    check for compressed writes.
    
    Signed-off-by: Kevin Wolf <kwolf@xxxxxxxxxx>
    Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
    (cherry picked from commit fbb7b4e0804d2168f24142eebf7552adde1968dc)
---
 block.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index 3261225..69c6da5 100644
--- a/block.c
+++ b/block.c
@@ -559,7 +559,10 @@ static int bdrv_check_byte_request(BlockDriverState *bs, 
int64_t offset,
 
     len = bdrv_getlength(bs);
 
-    if ((offset + size) > len)
+    if (offset < 0)
+        return -EIO;
+
+    if ((offset > len) || (len - offset < size))
         return -EIO;
 
     return 0;
@@ -1209,6 +1212,8 @@ int bdrv_write_compressed(BlockDriverState *bs, int64_t 
sector_num,
        return -EIO;
     if (!drv->bdrv_write_compressed)
         return -ENOTSUP;
+    if (bdrv_check_request(bs, sector_num, nb_sectors))
+        return -EIO;
     return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
 }
 
--
generated by git-patchbot for /home/xen/git/qemu-xen-unstable.git

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