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sg: prevent integer overflow when converting from sectors to bytes 

This prevents integer overflow when converting the request queue's
max_sectors from sectors to bytes.  However, this is a preparation for
extending the data type of max_sectors in struct Scsi_Host and
scsi_host_template.  So, it is impossible to happen this integer
overflow for now, because SCSI low-level drivers can not specify
max_sectors greater than 0xffff due to the data type limitation.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Akinobu Mita 2014-06-02 22:56:46 +09:00 committed by Christoph Hellwig
parent fcc95a7634
commit 46f69e6a6b
1 changed files with 13 additions and 4 deletions
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17
drivers/scsi/sg.c
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@ -806,6 +806,15 @@ static int srp_done(Sg_fd *sfp, Sg_request *srp)
return ret;
}
static int max_sectors_bytes(struct request_queue *q)
{
unsigned int max_sectors = queue_max_sectors(q);
max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
return max_sectors << 9;
}
static long
sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
@ -945,7 +954,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
if (val < 0)
return -EINVAL;
val = min_t(int, val,
queue_max_sectors(sdp->device->request_queue) * 512);
max_sectors_bytes(sdp->device->request_queue));
if (val != sfp->reserve.bufflen) {
if (sg_res_in_use(sfp) || sfp->mmap_called)
return -EBUSY;
@ -955,7 +964,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return 0;
case SG_GET_RESERVED_SIZE:
val = min_t(int, sfp->reserve.bufflen,
queue_max_sectors(sdp->device->request_queue) * 512);
max_sectors_bytes(sdp->device->request_queue));
return put_user(val, ip);
case SG_SET_COMMAND_Q:
result = get_user(val, ip);
@ -1095,7 +1104,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return -ENODEV;
return scsi_ioctl(sdp->device, cmd_in, p);
case BLKSECTGET:
return put_user(queue_max_sectors(sdp->device->request_queue) * 512,
return put_user(max_sectors_bytes(sdp->device->request_queue),
ip);
case BLKTRACESETUP:
return blk_trace_setup(sdp->device->request_queue,
@ -2085,7 +2094,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
sg_big_buff = def_reserved_size;
bufflen = min_t(int, sg_big_buff,
queue_max_sectors(sdp->device->request_queue) * 512);
max_sectors_bytes(sdp->device->request_queue));
sg_build_reserve(sfp, bufflen);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
sfp->reserve.bufflen, sfp->reserve.k_use_sg));