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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
This commit is contained in:
aliguori 2009-01-28 21:58:22 +00:00
parent baa8c60229
commit e035b43d7c
1 changed files with 6 additions and 3 deletions
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9
hw/scsi-disk.c
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@ -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;