From a5319d241b02f44f273b9283271b5017b45c0b50 Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Wed, 20 Nov 2013 19:43:58 +0100
Subject: [PATCH 15/25] block: vhdx - add region overlap detection for image files
RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <d98c86496e5956aa6bd9359f0f060982e1c44aa0.1384975172.git.jcody@redhat.com>
Patchwork-id: 55808
O-Subject: [RHEL7 qemu-kvm PATCH 15/26] block: vhdx - add region overlap detection for image files
Bugzilla: 879234
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
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 <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 1a848fd4517820981b542e0d10e64c0426414229)
---
block/vhdx.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/vhdx.h | 9 +++++++
2 files changed, 91 insertions(+)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
block/vhdx.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/vhdx.h | 9 ++++++
2 files changed, 91 insertions(+), 0 deletions(-)
diff --git a/block/vhdx.c b/block/vhdx.c
index b552dde..e36c60e 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 b150ad1..91ef8fe 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);
--
1.7.1