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[PULL,for-2.0,43/51] block: Limit request size (CVE-2014-0143)

Message ID 1396372769-11688-44-git-send-email-stefanha@redhat.com
State New
Headers show

Commit Message

Stefan Hajnoczi April 1, 2014, 5:19 p.m. UTC 
From: Kevin Wolf <kwolf@redhat.com>

Limiting the size of a single request to INT_MAX not only fixes a
direct integer overflow in bdrv_check_request() (which would only
trigger bad behaviour with ridiculously huge images, as in close to
2^64 bytes), but can also prevent overflows in all block drivers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/block.c b/block.c
index acb70fd..7a90a1b 100644
--- a/block.c
+++ b/block.c
@@ -2588,6 +2588,10 @@  static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
                               int nb_sectors)
 {
+    if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
+        return -EIO;
+    }
+
     return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
                                    nb_sectors * BDRV_SECTOR_SIZE);
 }