- Fix unchecked block read/write vulnerability [2] Submitted by: nox [1] Obtained from: qemu cvs [2] Security: http://www.vuxml.org/freebsd/9cfbca7f-efb7-11dc-be01-0211060005df.html
242 lines
8.3 KiB
Text
242 lines
8.3 KiB
Text
Index: qemu/block-qcow.c
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===================================================================
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RCS file: /sources/qemu/qemu/block-qcow.c,v
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retrieving revision 1.15
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retrieving revision 1.16
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diff -u -p -u -p -r1.15 -r1.16
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--- block-qcow.c 11 Nov 2007 02:51:16 -0000 1.15
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+++ block-qcow.c 11 Mar 2008 17:17:58 -0000 1.16
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@@ -95,7 +95,7 @@ static int qcow_open(BlockDriverState *b
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int len, i, shift, ret;
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QCowHeader header;
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- ret = bdrv_file_open(&s->hd, filename, flags);
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+ ret = bdrv_file_open(&s->hd, filename, flags | BDRV_O_AUTOGROW);
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if (ret < 0)
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return ret;
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if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
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Index: qemu/block-qcow2.c
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===================================================================
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RCS file: /sources/qemu/qemu/block-qcow2.c,v
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retrieving revision 1.10
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retrieving revision 1.11
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diff -u -p -u -p -r1.10 -r1.11
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--- block-qcow2.c 11 Nov 2007 02:51:16 -0000 1.10
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+++ block-qcow2.c 11 Mar 2008 17:17:58 -0000 1.11
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@@ -191,7 +191,7 @@ static int qcow_open(BlockDriverState *b
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int len, i, shift, ret;
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QCowHeader header;
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- ret = bdrv_file_open(&s->hd, filename, flags);
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+ ret = bdrv_file_open(&s->hd, filename, flags | BDRV_O_AUTOGROW);
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if (ret < 0)
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return ret;
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if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
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Index: qemu/block-vmdk.c
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===================================================================
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RCS file: /sources/qemu/qemu/block-vmdk.c,v
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retrieving revision 1.19
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retrieving revision 1.20
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diff -u -p -u -p -r1.19 -r1.20
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--- block-vmdk.c 14 Jan 2008 03:48:37 -0000 1.19
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+++ block-vmdk.c 11 Mar 2008 17:17:58 -0000 1.20
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@@ -378,7 +378,7 @@ static int vmdk_open(BlockDriverState *b
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flags = BDRV_O_RDONLY;
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fprintf(stderr, "(VMDK) image open: flags=0x%x filename=%s\n", flags, bs->filename);
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- ret = bdrv_file_open(&s->hd, filename, flags);
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+ ret = bdrv_file_open(&s->hd, filename, flags | BDRV_O_AUTOGROW);
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if (ret < 0)
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return ret;
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if (bdrv_pread(s->hd, 0, &magic, sizeof(magic)) != sizeof(magic))
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Index: qemu/block.c
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===================================================================
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RCS file: /sources/qemu/qemu/block.c,v
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retrieving revision 1.54
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retrieving revision 1.55
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diff -u -p -u -p -r1.54 -r1.55
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--- block.c 10 Mar 2008 00:05:34 -0000 1.54
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+++ block.c 11 Mar 2008 17:17:58 -0000 1.55
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@@ -123,6 +123,60 @@ void path_combine(char *dest, int dest_s
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}
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}
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+static int bdrv_rd_badreq_sectors(BlockDriverState *bs,
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+ int64_t sector_num, int nb_sectors)
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+{
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+ return
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+ nb_sectors < 0 ||
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+ sector_num < 0 ||
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+ nb_sectors > bs->total_sectors ||
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+ sector_num > bs->total_sectors - nb_sectors;
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+}
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+
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+static int bdrv_rd_badreq_bytes(BlockDriverState *bs,
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+ int64_t offset, int count)
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+{
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+ int64_t size = bs->total_sectors << SECTOR_BITS;
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+ return
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+ count < 0 ||
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+ size < 0 ||
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+ count > size ||
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+ offset > size - count;
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+}
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+
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+static int bdrv_wr_badreq_sectors(BlockDriverState *bs,
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+ int64_t sector_num, int nb_sectors)
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+{
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+ if (sector_num < 0 ||
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+ nb_sectors < 0)
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+ return 1;
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+
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+ if (sector_num > bs->total_sectors - nb_sectors) {
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+ if (bs->autogrow)
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+ bs->total_sectors = sector_num + nb_sectors;
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+ else
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+ return 1;
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+ }
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+ return 0;
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+}
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+
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+static int bdrv_wr_badreq_bytes(BlockDriverState *bs,
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+ int64_t offset, int count)
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+{
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+ int64_t size = bs->total_sectors << SECTOR_BITS;
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+ if (count < 0 ||
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+ offset < 0)
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+ return 1;
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+
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+ if (offset > size - count) {
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+ if (bs->autogrow)
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+ bs->total_sectors = (offset + count + SECTOR_SIZE - 1) >> SECTOR_BITS;
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+ else
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+ return 1;
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+ }
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+ return 0;
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+}
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+
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static void bdrv_register(BlockDriver *bdrv)
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{
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@@ -335,6 +389,10 @@ int bdrv_open2(BlockDriverState *bs, con
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bs->read_only = 0;
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bs->is_temporary = 0;
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bs->encrypted = 0;
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+ bs->autogrow = 0;
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+
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+ if (flags & BDRV_O_AUTOGROW)
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+ bs->autogrow = 1;
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if (flags & BDRV_O_SNAPSHOT) {
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BlockDriverState *bs1;
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@@ -379,6 +437,7 @@ int bdrv_open2(BlockDriverState *bs, con
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}
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bs->drv = drv;
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bs->opaque = qemu_mallocz(drv->instance_size);
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+ bs->total_sectors = 0; /* driver will set if it does not do getlength */
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if (bs->opaque == NULL && drv->instance_size > 0)
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return -1;
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/* Note: for compatibility, we open disk image files as RDWR, and
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@@ -444,6 +503,7 @@ void bdrv_close(BlockDriverState *bs)
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bs->drv = NULL;
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/* call the change callback */
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+ bs->total_sectors = 0;
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bs->media_changed = 1;
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if (bs->change_cb)
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bs->change_cb(bs->change_opaque);
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@@ -509,6 +569,8 @@ int bdrv_read(BlockDriverState *bs, int6
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if (!drv)
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return -ENOMEDIUM;
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+ if (bdrv_rd_badreq_sectors(bs, sector_num, nb_sectors))
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+ return -EDOM;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(buf, bs->boot_sector_data, 512);
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sector_num++;
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@@ -549,6 +611,8 @@ int bdrv_write(BlockDriverState *bs, int
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return -ENOMEDIUM;
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if (bs->read_only)
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return -EACCES;
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+ if (bdrv_wr_badreq_sectors(bs, sector_num, nb_sectors))
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+ return -EDOM;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(bs->boot_sector_data, buf, 512);
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}
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@@ -674,6 +738,8 @@ int bdrv_pread(BlockDriverState *bs, int
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return -ENOMEDIUM;
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if (!drv->bdrv_pread)
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return bdrv_pread_em(bs, offset, buf1, count1);
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+ if (bdrv_rd_badreq_bytes(bs, offset, count1))
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+ return -EDOM;
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return drv->bdrv_pread(bs, offset, buf1, count1);
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}
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@@ -689,6 +755,8 @@ int bdrv_pwrite(BlockDriverState *bs, in
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return -ENOMEDIUM;
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if (!drv->bdrv_pwrite)
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return bdrv_pwrite_em(bs, offset, buf1, count1);
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+ if (bdrv_wr_badreq_bytes(bs, offset, count1))
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+ return -EDOM;
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return drv->bdrv_pwrite(bs, offset, buf1, count1);
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}
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@@ -955,6 +1023,8 @@ int bdrv_write_compressed(BlockDriverSta
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return -ENOMEDIUM;
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if (!drv->bdrv_write_compressed)
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return -ENOTSUP;
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+ if (bdrv_wr_badreq_sectors(bs, sector_num, nb_sectors))
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+ return -EDOM;
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return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
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}
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@@ -1101,6 +1171,8 @@ BlockDriverAIOCB *bdrv_aio_read(BlockDri
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if (!drv)
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return NULL;
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+ if (bdrv_rd_badreq_sectors(bs, sector_num, nb_sectors))
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+ return NULL;
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/* XXX: we assume that nb_sectors == 0 is suppored by the async read */
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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@@ -1132,6 +1204,8 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDr
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return NULL;
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if (bs->read_only)
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return NULL;
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+ if (bdrv_wr_badreq_sectors(bs, sector_num, nb_sectors))
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+ return NULL;
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if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
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memcpy(bs->boot_sector_data, buf, 512);
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}
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Index: qemu/block.h
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===================================================================
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RCS file: /sources/qemu/qemu/block.h,v
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retrieving revision 1.6
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retrieving revision 1.7
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diff -u -p -u -p -r1.6 -r1.7
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--- block.h 24 Dec 2007 16:10:43 -0000 1.6
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+++ block.h 11 Mar 2008 17:17:59 -0000 1.7
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@@ -45,6 +45,7 @@ typedef struct QEMUSnapshotInfo {
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it (default for
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bdrv_file_open()) */
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#define BDRV_O_DIRECT 0x0020
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+#define BDRV_O_AUTOGROW 0x0040 /* Allow backing file to extend when writing past end of file */
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#ifndef QEMU_IMG
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void bdrv_info(void);
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Index: qemu/block_int.h
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===================================================================
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RCS file: /sources/qemu/qemu/block_int.h,v
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retrieving revision 1.16
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retrieving revision 1.17
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diff -u -p -u -p -r1.16 -r1.17
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--- block_int.h 24 Dec 2007 16:10:43 -0000 1.16
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+++ block_int.h 11 Mar 2008 17:17:59 -0000 1.17
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@@ -97,6 +97,7 @@ struct BlockDriverState {
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int locked; /* if true, the media cannot temporarily be ejected */
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int encrypted; /* if true, the media is encrypted */
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int sg; /* if true, the device is a /dev/sg* */
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+ int autogrow; /* if true, the backing store can auto-extend to allocate new extents */
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/* event callback when inserting/removing */
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void (*change_cb)(void *opaque);
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void *change_opaque;
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