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Re: [Qemu-devel] [PATCH for-2.11 4/5] qcow2: Add bounds check to get_ref
From: |
Alberto Garcia |
Subject: |
Re: [Qemu-devel] [PATCH for-2.11 4/5] qcow2: Add bounds check to get_refblock_offset() |
Date: |
Tue, 14 Nov 2017 16:02:49 +0100 |
User-agent: |
Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) |
On Fri 10 Nov 2017 09:31:10 PM CET, Max Reitz wrote:
> +static int64_t get_refblock_offset(BlockDriverState *bs, uint64_t offset)
> +{
> + BDRVQcow2State *s = bs->opaque;
> + uint32_t index = offset_to_reftable_index(s, offset);
> + int64_t covering_refblock_offset = 0;
> +
> + if (index < s->refcount_table_size) {
> + covering_refblock_offset = s->refcount_table[index] &
> REFT_OFFSET_MASK;
> + }
> + if (!covering_refblock_offset) {
> + qcow2_signal_corruption(bs, true, -1, -1, "Refblock at %#" PRIx64 "
> is "
> + "not covered by the refcount structures",
> + offset);
> + return -EIO;
> + }
> +
> + return covering_refblock_offset;
> +}
Isn't it simpler to do something like this instead?
if (index >= s->refcount_table_size) {
qcow2_signal_corruption(...);
return -EIO;
}
return s->refcount_table[index] & REFT_OFFSET_MASK;
Berto
- [Qemu-devel] [PATCH for-2.11 1/5] qcow2: check_errors are fatal, (continued)
[Qemu-devel] [PATCH for-2.11 5/5] qcow2: Refuse to get unaligned offsets from cache, Max Reitz, 2017/11/10
Re: [Qemu-devel] [PATCH for-2.11 5/5] qcow2: Refuse to get unaligned offsets from cache, Alberto Garcia, 2017/11/14