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[PULL,04/20] block: fix theoretical overflow in bdrv_init_padding()

Message ID 20210202224529.642055-5-eblake@redhat.com
State New
Headers show
Series [PULL,01/20] iotests: Fix expected whitespace for 185 | expand

Commit Message

Eric Blake Feb. 2, 2021, 10:45 p.m. UTC 
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Calculation of sum may theoretically overflow, so use 64bit type and
add some good assertions.

Use int64_t constantly.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: tweak assertion order]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
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Patch

diff --git a/block/io.c b/block/io.c
index ab953bd58f48..c8c9dea55466 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1565,8 +1565,12 @@  static bool bdrv_init_padding(BlockDriverState *bs,
                               int64_t offset, int64_t bytes,
                               BdrvRequestPadding *pad)
 {
-    uint64_t align = bs->bl.request_alignment;
-    size_t sum;
+    int64_t align = bs->bl.request_alignment;
+    int64_t sum;
+
+    bdrv_check_request(offset, bytes, &error_abort);
+    assert(align <= INT_MAX); /* documented in block/block_int.h */
+    assert(align <= SIZE_MAX / 2); /* so we can allocate the buffer */

     memset(pad, 0, sizeof(*pad));