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[Qemu-devel] [PATCH v5 09/16] block: vhdx - add region overlap detection
From: |
Jeff Cody |
Subject: |
[Qemu-devel] [PATCH v5 09/16] block: vhdx - add region overlap detection for image files |
Date: |
Tue, 3 Sep 2013 15:53:17 -0400 |
Regions in the image file cannot overlap - the log, region tables,
and metdata must all be unique and non-overlapping.
This adds region checking by means of a QLIST; there can be a variable
number of regions and metadata (there may be metadata or region tables
that we do not recognize / know about, but are not required).
This adds the capability to register a region for later checking, and
to check against registered regions for any overlap.
Also, if neither the BAT or Metadata region tables are found, return
error.
Signed-off-by: Jeff Cody <address@hidden>
---
block/vhdx.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/vhdx.h | 8 ++++++
2 files changed, 91 insertions(+)
diff --git a/block/vhdx.c b/block/vhdx.c
index d0499ba..b15d6e5 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -203,6 +203,51 @@ void vhdx_guid_generate(MSGUID *guid)
memcpy(guid, uuid, sizeof(MSGUID));
}
+/* Check for region overlaps inside the VHDX image */
+static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
+{
+ int ret = 0;
+ uint64_t end;
+ VHDXRegionEntry *r;
+
+ end = start + length;
+ QLIST_FOREACH(r, &s->regions, entries) {
+ if ((start >= r->start && start < r->end) ||
+ (end > r->start && end <= r->end)) {
+ ret = -EINVAL;
+ goto exit;
+ }
+ }
+
+exit:
+ return ret;
+}
+
+/* Register a region for future checks */
+static void vhdx_region_register(BDRVVHDXState *s,
+ uint64_t start, uint64_t length)
+{
+ VHDXRegionEntry *r;
+
+ r = g_malloc0(sizeof(*r));
+
+ r->start = start;
+ r->end = start + length;
+
+ QLIST_INSERT_HEAD(&s->regions, r, entries);
+}
+
+/* Free all registered regions */
+static void vhdx_region_unregister_all(BDRVVHDXState *s)
+{
+ VHDXRegionEntry *r, *r_next;
+
+ QLIST_FOREACH_SAFE(r, &s->regions, entries, r_next) {
+ QLIST_REMOVE(r, entries);
+ g_free(r);
+ }
+}
+
/*
* Per the MS VHDX Specification, for every VHDX file:
* - The header section is fixed size - 1 MB
@@ -388,6 +433,9 @@ static int vhdx_parse_header(BlockDriverState *bs,
BDRVVHDXState *s)
}
}
+ vhdx_region_register(s, s->headers[s->curr_header]->log_offset,
+ s->headers[s->curr_header]->log_length);
+
ret = 0;
goto exit;
@@ -451,6 +499,15 @@ static int vhdx_open_region_tables(BlockDriverState *bs,
BDRVVHDXState *s)
le32_to_cpus(&rt_entry.length);
le32_to_cpus(&rt_entry.data_bits);
+ /* check for region overlap between these entries, and any
+ * other memory regions in the file */
+ ret = vhdx_region_check(s, rt_entry.file_offset, rt_entry.length);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ vhdx_region_register(s, rt_entry.file_offset, rt_entry.length);
+
/* see if we recognize the entry */
if (guid_eq(rt_entry.guid, bat_guid)) {
/* must be unique; if we have already found it this is invalid */
@@ -481,6 +538,12 @@ static int vhdx_open_region_tables(BlockDriverState *bs,
BDRVVHDXState *s)
goto fail;
}
}
+
+ if (!bat_rt_found || !metadata_rt_found) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
ret = 0;
fail:
@@ -743,6 +806,7 @@ static void vhdx_close(BlockDriverState *bs)
qemu_vfree(s->bat);
qemu_vfree(s->parent_entries);
qemu_vfree(s->log.hdr);
+ vhdx_region_unregister_all(s);
}
static int vhdx_open(BlockDriverState *bs, QDict *options, int flags)
@@ -760,6 +824,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options,
int flags)
s->log.write = s->log.read = 0;
qemu_co_mutex_init(&s->lock);
+ QLIST_INIT(&s->regions);
/* validate the file signature */
ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
@@ -846,8 +911,26 @@ static int vhdx_open(BlockDriverState *bs, QDict *options,
int flags)
goto fail;
}
+ uint64_t payblocks = s->chunk_ratio;
+ /* endian convert, and verify populated BAT field file offsets against
+ * region table and log entries */
for (i = 0; i < s->bat_entries; i++) {
le64_to_cpus(&s->bat[i]);
+ if (payblocks--) {
+ /* payload bat entries */
+ if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
+ PAYLOAD_BLOCK_FULL_PRESENT) {
+ ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
+ s->block_size);
+ if (ret < 0) {
+ goto fail;
+ }
+ }
+ } else {
+ payblocks = s->chunk_ratio;
+ /* Once differencing files are supported, verify sector bitmap
+ * blocks here */
+ }
}
if (flags & BDRV_O_RDWR) {
diff --git a/block/vhdx.h b/block/vhdx.h
index dfb3ed9..831aa13 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -230,6 +230,7 @@ typedef struct QEMU_PACKED VHDXLogDataSector {
other bits are reserved */
#define VHDX_BAT_STATE_BIT_MASK 0x07
#define VHDX_BAT_FILE_OFF_BITS (64 - 44)
+#define VHDX_BAT_FILE_OFF_MASK 0xFFFFFFFFFFF00000 /* upper 44 bits */
typedef uint64_t VHDXBatEntry;
/* ---- METADATA REGION STRUCTURES ---- */
@@ -334,6 +335,12 @@ typedef struct VHDXLogEntries {
uint32_t tail;
} VHDXLogEntries;
+typedef struct VHDXRegionEntry {
+ uint64_t start;
+ uint64_t end;
+ QLIST_ENTRY(VHDXRegionEntry) entries;
+} VHDXRegionEntry;
+
typedef struct BDRVVHDXState {
CoMutex lock;
@@ -373,6 +380,7 @@ typedef struct BDRVVHDXState {
VHDXParentLocatorHeader parent_header;
VHDXParentLocatorEntry *parent_entries;
+ QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
} BDRVVHDXState;
void vhdx_guid_generate(MSGUID *guid);
--
1.8.1.4
- [Qemu-devel] [PATCH v5 00/16] VHDX log replay and write support, .bdrv_create(), Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 01/16] block: vhdx - minor comments and typo correction., Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 02/16] block: vhdx - add header update capability., Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 03/16] block: vhdx code movement - VHDXMetadataEntries and BDRVVHDXState to header., Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 04/16] block: vhdx - log support struct and defines, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 05/16] block: vhdx - break endian translation functions out, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 06/16] block: vhdx - update log guid in header, and first write tracker, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 07/16] block: vhdx code movement - move vhdx_close() above vhdx_open(), Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 08/16] block: vhdx - log parsing, replay, and flush support, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 09/16] block: vhdx - add region overlap detection for image files,
Jeff Cody <=
- [Qemu-devel] [PATCH v5 10/16] block: vhdx - add log write support, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 11/16] block: vhdx write support, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 12/16] block: vhdx - remove BAT file offset bit shifting, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 13/16] block: vhdx - move more endian translations to vhdx-endian.c, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 14/16] block: vhdx - break out code operations to functions, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 15/16] block: vhdx - fix comment typos in header, fix incorrect struct fields, Jeff Cody, 2013/09/03
- [Qemu-devel] [PATCH v5 16/16] block: vhdx - add .bdrv_create() support, Jeff Cody, 2013/09/03