[Xen-changelog] [linux-2.6.18-xen] blkback: Sanity-check nr_segments parameter.

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1194546368 0
# Node ID cf8b6cafa2f0a8ba698322786cc78ae28a1b0f60
# Parent  f539cd7c933160670e2709f3954269883f9f5284
blkback: Sanity-check nr_segments parameter.
From: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
---
 include/xen/blkif.h |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff -r f539cd7c9331 -r cf8b6cafa2f0 include/xen/blkif.h
--- a/include/xen/blkif.h       Wed Nov 07 15:19:39 2007 -0700
+++ b/include/xen/blkif.h       Thu Nov 08 18:26:08 2007 +0000
@@ -72,25 +72,29 @@ enum blkif_protocol {
 
 static void inline blkif_get_x86_32_req(blkif_request_t *dst, 
blkif_x86_32_request_t *src)
 {
-       int i;
+       int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
        dst->operation = src->operation;
        dst->nr_segments = src->nr_segments;
        dst->handle = src->handle;
        dst->id = src->id;
        dst->sector_number = src->sector_number;
-       for (i = 0; i < src->nr_segments; i++)
+       if (n > src->nr_segments)
+               n = src->nr_segments;
+       for (i = 0; i < n; i++)
                dst->seg[i] = src->seg[i];
 }
 
 static void inline blkif_get_x86_64_req(blkif_request_t *dst, 
blkif_x86_64_request_t *src)
 {
-       int i;
+       int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
        dst->operation = src->operation;
        dst->nr_segments = src->nr_segments;
        dst->handle = src->handle;
        dst->id = src->id;
        dst->sector_number = src->sector_number;
-       for (i = 0; i < src->nr_segments; i++)
+       if (n > src->nr_segments)
+               n = src->nr_segments;
+       for (i = 0; i < n; i++)
                dst->seg[i] = src->seg[i];
 }
 

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