63 lines
2.0 KiB
Diff
63 lines
2.0 KiB
Diff
From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Wed, 26 Mar 2014 13:05:26 +0100
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Subject: [PATCH] block/cloop: prevent offsets_size integer overflow
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(CVE-2014-0143)
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The following integer overflow in offsets_size can lead to out-of-bounds
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memory stores when n_blocks has a huge value:
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uint32_t n_blocks, offsets_size;
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[...]
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ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4);
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[...]
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s->n_blocks = be32_to_cpu(s->n_blocks);
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/* read offsets */
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offsets_size = s->n_blocks * sizeof(uint64_t);
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s->offsets = g_malloc(offsets_size);
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[...]
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for(i=0;i<s->n_blocks;i++) {
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s->offsets[i] = be64_to_cpu(s->offsets[i]);
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offsets_size can be smaller than n_blocks due to integer overflow.
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Therefore s->offsets[] is too small when the for loop byteswaps offsets.
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This patch refuses to open files if offsets_size would overflow.
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Note that changing the type of offsets_size is not a fix since 32-bit
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hosts still only have 32-bit size_t.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit 509a41bab5306181044b5fff02eadf96d9c8676a)
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Conflicts:
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tests/qemu-iotests/075
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tests/qemu-iotests/075.out
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---
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block/cloop.c | 7 +++++++
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1 file changed, 7 insertions(+)
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diff --git a/block/cloop.c b/block/cloop.c
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index c2441b0..e20d0d8 100644
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--- a/block/cloop.c
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+++ b/block/cloop.c
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@@ -98,6 +98,13 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags)
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s->n_blocks = be32_to_cpu(s->n_blocks);
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/* read offsets */
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+ if (s->n_blocks > UINT32_MAX / sizeof(uint64_t)) {
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+ /* Prevent integer overflow */
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+ fprintf(stderr, "n_blocks %u must be %zu or less",
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+ s->n_blocks,
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+ UINT32_MAX / sizeof(uint64_t));
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+ return -EINVAL;
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+ }
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offsets_size = s->n_blocks * sizeof(uint64_t);
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s->offsets = g_malloc(offsets_size);
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