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[Qemu-devel] [PULL v2 26/37] block: vhdx - add region overlap detection
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL v2 26/37] block: vhdx - add region overlap detection for image files |
Date: |
Fri, 8 Nov 2013 11:12:20 +0100 |
From: Jeff Cody <address@hidden>
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>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/vhdx.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/vhdx.h | 9 +++++++
2 files changed, 91 insertions(+)
diff --git a/block/vhdx.c b/block/vhdx.c
index 8fbfbd6..574ac4c 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -204,6 +204,50 @@ 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->end) || (end <= r->start))) {
+ 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
@@ -389,6 +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;
@@ -452,6 +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 */
@@ -482,6 +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:
@@ -751,6 +813,7 @@ static void vhdx_close(BlockDriverState *bs)
error_free(s->migration_blocker);
qemu_vfree(s->log.hdr);
s->log.hdr = NULL;
+ vhdx_region_unregister_all(s);
}
static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
@@ -768,6 +831,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options,
int flags,
s->first_visible_write = true;
qemu_co_mutex_init(&s->lock);
+ QLIST_INIT(&s->regions);
/* validate the file signature */
ret = bdrv_pread(bs->file, 0, &signature, sizeof(uint64_t));
@@ -842,8 +906,26 @@ 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 584ebec..d906559 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;
@@ -374,6 +381,8 @@ typedef struct BDRVVHDXState {
VHDXParentLocatorEntry *parent_entries;
Error *migration_blocker;
+
+ QLIST_HEAD(VHDXRegionHead, VHDXRegionEntry) regions;
} BDRVVHDXState;
void vhdx_guid_generate(MSGUID *guid);
--
1.8.3.1
- [Qemu-devel] [PULL v2 07/37] block: qemu-iotests, add quotes to $TEST_IMG usage in 019, (continued)
- [Qemu-devel] [PULL v2 07/37] block: qemu-iotests, add quotes to $TEST_IMG usage in 019, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 08/37] block: qemu-iotests, removes duplicate double quotes in 039, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 33/37] block: vhdx - add .bdrv_create() support, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 37/37] block: Round up total_sectors, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 10/37] block: qemu-iotests, add quotes to $TEST_IMG usage in 061, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 36/37] block: vhdx qemu-iotest - log replay of data sector, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 11/37] blockdev: fix drive_init() opts and bs_opts leaks, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 15/37] qdev-monitor-test: add device_add leak test cases, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 21/37] block: vhdx - log support struct and defines, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 22/37] block: vhdx - break endian translation functions out, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 26/37] block: vhdx - add region overlap detection for image files,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL v2 28/37] block: vhdx write support, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 31/37] block: vhdx - break out code operations to functions, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 35/37] block: qemu-iotests for vhdx, add write test support, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 34/37] block: vhdx - update _make_test_img() to filter out vhdx options, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 23/37] block: vhdx - update log guid in header, and first write tracker, Stefan Hajnoczi, 2013/11/08
- [Qemu-devel] [PULL v2 19/37] block: vhdx - add header update capability., Stefan Hajnoczi, 2013/11/08