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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-01-28 21:58:22 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-01-28 21:58:22 +0000
commite035b43d7c98b1509420d41b017abcdac0de0442 (patch)
tree2dccc84bb2394e3b5d5b56474abea2ab24c72a64 /hw/scsi-disk.c
parentbaa8c602295b1d33844503ce0a172b85f84646d3 (diff)
fix signed/unsigned overflows in SCSI disk (Rik van Riel)
Sector numbers can overflow on a virtual scsi disk of over 1TB in size. Qemu's bdrv_read expects an int64_t, so fix the overflow by going to that data type. On large disks, we clip the capacity to 2TB instead of returning "capacity modulo 2TB". Turn sector_count into an unsigned to prevent a signed/unsigned overflow with SCSI transfers larger than 2TB. We're unlikely to ever hit this bug, but fixing it is just one line. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6467 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'hw/scsi-disk.c')
-rw-r--r--hw/scsi-disk.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 2a571a0f16..89b44c31b7 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -47,11 +47,11 @@ do { fprintf(stderr, "scsi-disk: " fmt , ##args); } while (0)
typedef struct SCSIRequest {
SCSIDeviceState *dev;
uint32_t tag;
- /* ??? We should probably keep track of whether the data trasfer is
+ /* ??? We should probably keep track of whether the data transfer is
a read or a write. Currently we rely on the host getting it right. */
/* Both sector and sector_count are in terms of qemu 512 byte blocks. */
- int sector;
- int sector_count;
+ uint64_t sector;
+ uint32_t sector_count;
/* The amounnt of data in the buffer. */
int buf_len;
uint8_t *dma_buf;
@@ -731,6 +731,9 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
/* Returned value is the address of the last sector. */
if (nb_sectors) {
nb_sectors--;
+ /* Clip to 2TB, instead of returning capacity modulo 2TB. */
+ if (nb_sectors > UINT32_MAX)
+ nb_sectors = UINT32_MAX;
outbuf[0] = (nb_sectors >> 24) & 0xff;
outbuf[1] = (nb_sectors >> 16) & 0xff;
outbuf[2] = (nb_sectors >> 8) & 0xff;