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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2014-03-26 13:05:58 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-04-01 15:22:35 +0200 |
| commit | c165f7758009a4f793c1fc19ebb69cf55313450b (patch) | |
| tree | 1df17ab2f0ad8c601252cc2e363b7de4ec77e050 /block/dmg.c | |
| parent | eb71803b041f55779ea10d860c0f66df285c68de (diff) | |
| download | qemu-c165f7758009a4f793c1fc19ebb69cf55313450b.tar.gz | |
dmg: sanitize chunk length and sectorcount (CVE-2014-0145)
Chunk length and sectorcount are used for decompression buffers as well
as the bdrv_pread() count argument. Ensure that they have reasonable
values so neither memory allocation nor conversion from uint64_t to int
will cause problems.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/dmg.c')
| -rw-r--r-- | block/dmg.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/block/dmg.c b/block/dmg.c index f98c94dc47..ad253fe1ed 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -27,6 +27,14 @@ #include "qemu/module.h" #include <zlib.h> +enum { + /* Limit chunk sizes to prevent unreasonable amounts of memory being used + * or truncating when converting to 32-bit types + */ + DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ + DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, +}; + typedef struct BDRVDMGState { CoMutex lock; /* each chunk contains a certain number of sectors, @@ -208,6 +216,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags, } offset += 8; + if (s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { + error_report("sector count %" PRIu64 " for chunk %u is " + "larger than max (%u)", + s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); + ret = -EINVAL; + goto fail; + } + ret = read_uint64(bs, offset, &s->offsets[i]); if (ret < 0) { goto fail; @@ -221,6 +237,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags, } offset += 8; + if (s->lengths[i] > DMG_LENGTHS_MAX) { + error_report("length %" PRIu64 " for chunk %u is larger " + "than max (%u)", + s->lengths[i], i, DMG_LENGTHS_MAX); + ret = -EINVAL; + goto fail; + } + if (s->lengths[i] > max_compressed_size) { max_compressed_size = s->lengths[i]; } |