scsi: sg: only check for dxfer_len greater than 256M (f930c704) · Commits · 戴 / test

Don't make any assumptions on the sg_io_hdr_t::dxfer_direction or the sg_io_hdr_t::dxferp in order to determine if it is a valid request. The only way we can check for bad requests is by checking if the length exceeds 256M. Signed-off-by:

Johannes Thumshirn <jthumshirn@suse.de> Fixes: (scsi: sg: check for valid direction before starting the request) Reported-by:

Jason L Tibbitts III <tibbs@math.uh.edu> Tested-by:

Jason L Tibbitts III <tibbs@math.uh.edu> Suggested-by:

Doug Gilbert <dgilbert@interlog.com> Cc: Doug Gilbert <dgilbert@interlog.com> Cc: <stable@vger.kernel.org> Reviewed-by:

Hannes Reinecke <hare@suse.com> Signed-off-by:

Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sg.c

+1 −30

Original line number	Diff line number	Diff line
		@@ -751,35 +751,6 @@ sg_new_write(Sg_fd sfp, struct file file, const char __user *buf,
		return count;
		}

		static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
		{
		switch (hp->dxfer_direction) {
		case SG_DXFER_NONE:
		if (hp->dxferp \|\| hp->dxfer_len > 0)
		return false;
		return true;
		case SG_DXFER_FROM_DEV:
		/*
		* for SG_DXFER_FROM_DEV we always set dxfer_len to > 0. dxferp
		* can either be NULL or != NULL so there's no point in checking
		* it either. So just return true.
		*/
		return true;
		case SG_DXFER_TO_DEV:
		case SG_DXFER_TO_FROM_DEV:
		if (!hp->dxferp \|\| hp->dxfer_len == 0)
		return false;
		return true;
		case SG_DXFER_UNKNOWN:
		if ((!hp->dxferp && hp->dxfer_len) \|\|
		(hp->dxferp && hp->dxfer_len == 0))
		return false;
		return true;
		default:
		return false;
		}
		}

		static int
		sg_common_write(Sg_fd * sfp, Sg_request * srp,
		unsigned char *cmnd, int timeout, int blocking)
		@@ -800,7 +771,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
		"sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n",
		(int) cmnd[0], (int) hp->cmd_len));

		if (!sg_is_valid_dxfer(hp))
		if (hp->dxfer_len >= SZ_256M)
		return -EINVAL;

		k = sg_start_req(srp, cmnd);

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