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authorPeter Wu <peter@lekensteyn.nl>2015-01-06 18:48:11 +0100
committerKevin Wolf <kwolf@redhat.com>2015-02-06 17:24:21 +0100
commitc6d34865fa02463cf34634f45369ebcc725b101b (patch)
tree685cb55ed16e4512a4739dd21c1a61dae05321a7 /block
parent8daf425794ed624083de98caab04b9fedb873420 (diff)
downloadhqemu-c6d34865fa02463cf34634f45369ebcc725b101b.zip
hqemu-c6d34865fa02463cf34634f45369ebcc725b101b.tar.gz
block/dmg: fix sector data offset calculation
This patch addresses two issues: - The data fork offset was not taken into account, resulting in failure to read an InstallESD.dmg file (5164763151 bytes) which had a non-zero DataForkOffset field. - The offset of the previous block ("partition") was unconditionally added to the current block because older files would start the input offset of a new block at zero. Newer files (including vlc-2.1.5.dmg, tuxpaint-0.9.15-macosx.dmg and OS X Yosemite [MAS].dmg) failed in reads because these files have chunk offsets, relative to the begin of a data fork. Now the data offset of the mish is taken into account. While we could check that the data_offset is within the data fork, let's not do that here as it would only result in parse failures on invalid files (rather than gracefully handling such bad files). dmg_read will error out if the offset is incorrect. Signed-off-by: Peter Wu <peter@lekensteyn.nl> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 1420566495-13284-9-git-send-email-peter@lekensteyn.nl Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/dmg.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/block/dmg.c b/block/dmg.c
index a33c131..34dc632 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -186,7 +186,7 @@ static int64_t dmg_find_koly_offset(BlockDriverState *file_bs, Error **errp)
typedef struct DmgHeaderState {
/* used internally by dmg_read_mish_block to remember offsets of blocks
* across calls */
- uint64_t last_in_offset;
+ uint64_t data_fork_offset;
uint64_t last_out_offset;
/* exported for dmg_open */
uint32_t max_compressed_size;
@@ -201,6 +201,8 @@ static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
size_t new_size;
uint32_t chunk_count;
int64_t offset = 0;
+ uint64_t data_offset;
+ uint64_t in_offset = ds->data_fork_offset;
type = buff_read_uint32(buffer, offset);
/* skip data that is not a valid MISH block (invalid magic or too small) */
@@ -209,8 +211,12 @@ static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
return 0;
}
- offset += 4;
- offset += 200;
+ /* location in data fork for (compressed) blob (in bytes) */
+ data_offset = buff_read_uint64(buffer, offset + 0x18);
+ in_offset += data_offset;
+
+ /* move to begin of chunk entries */
+ offset += 204;
chunk_count = (count - 204) / 40;
new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
@@ -226,7 +232,6 @@ static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
if (s->types[i] != 0x80000005 && s->types[i] != 1 &&
s->types[i] != 2) {
if (s->types[i] == 0xffffffff && i > 0) {
- ds->last_in_offset = s->offsets[i - 1] + s->lengths[i - 1];
ds->last_out_offset = s->sectors[i - 1] +
s->sectorcounts[i - 1];
}
@@ -253,7 +258,7 @@ static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
}
s->offsets[i] = buff_read_uint64(buffer, offset);
- s->offsets[i] += ds->last_in_offset;
+ s->offsets[i] += in_offset;
offset += 8;
s->lengths[i] = buff_read_uint64(buffer, offset);
@@ -412,7 +417,7 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
s->n_chunks = 0;
s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
/* used by dmg_read_mish_block to keep track of the current I/O position */
- ds.last_in_offset = 0;
+ ds.data_fork_offset = 0;
ds.last_out_offset = 0;
ds.max_compressed_size = 1;
ds.max_sectors_per_chunk = 1;
@@ -424,6 +429,15 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
goto fail;
}
+ /* offset of data fork (DataForkOffset) */
+ ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset);
+ if (ret < 0) {
+ goto fail;
+ } else if (ds.data_fork_offset > offset) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
/* offset of resource fork (RsrcForkOffset) */
ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset);
if (ret < 0) {
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