Fix mtx (rhbz 1471302)

bz1471302.patch

@@ -0,0 +1,81 @@
+From: Johannes Thumshirn <jthumshirn@suse.de>
+Subject: Re: [REGRESSION] 28676d869bbb (scsi: sg: check for valid direction
+ before starting the request) breaks mtx tape library control
+To: Jason L Tibbitts III <tibbs@math.uh.edu>
+Cc: Doug Gilbert <dgilbert@interlog.com>, linux-scsi@vger.kernel.org,
+	linux-kernel@vger.kernel.org, dvyukov@google.com, hare@suse.com,
+	hch@lst.de, martin.petersen@oracle.com
+Date: Wed, 26 Jul 2017 09:39:34 +0200 (6 hours, 57 minutes ago)
+
+On Tue, Jul 25, 2017 at 01:25:07PM -0500, Jason L Tibbitts III wrote:
+> >>>>> "JT" == Johannes Thumshirn <jthumshirn@suse.de> writes:
+> ioctl(3, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_TO_DEV, cmd_len=12, cmdp="\xa5\x00\x00\x00\x00\x01\x03\xe9\x00\x00\x00\x00", mx_sb_len=20, iovec_count=0, dxfer_len=0, timeout=300000, flags=0, dxferp=NULL, status=0, masked_status=0, msg_status=0, sb_len_wr=0, sbp="", host_status=0, driver_status=0, resid=0, duration=0, info=0}) = -1 EINVAL (Invalid argument)
+
+[...]
+ 	case SG_DXFER_TO_DEV:
+  	case SG_DXFER_TO_FROM_DEV:
+ 		if (!hp->dxferp)
+  			return false;
+  		return true;
+
+So here we go, dxfer_direction is SG_DXFER_TO_DEV, dxfer_len is 0 and dxferp
+is NULL. We bail out because dxferp is NULL here.
+
+I only looked at sg_write() and not sg_new_write() which is called by the
+SG_IO path not the fops->write() path.
+
+It's probably best to just check for dxfer_len <= 2^28 to be valid as Doug
+suggested:
+
+diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
+index 4fe606b000b4..d7ff71e0c85c 100644
+--- a/drivers/scsi/sg.c
++++ b/drivers/scsi/sg.c
+@@ -751,29 +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_TO_DEV:
+-	case SG_DXFER_FROM_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);
+
+-- 
+Johannes Thumshirn                                          Storage
+jthumshirn@suse.de                                +49 911 74053 689
+SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
+GF: Felix Imendörffer, Jane Smithard, Graham Norton
+HRB 21284 (AG Nürnberg)
+Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
+

kernel.spec

@@ -675,6 +675,9 @@ Patch702: CVE-2017-11473.patch
 Patch703: HID-rmi-Make-sure-the-HID-device-is-opened-on-resume.patch
 Patch704: input-rmi4-remove-the-need-for-artifical-IRQ.patch
 
+# rhbz 1471302
+Patch705: bz1471302.patch 
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -2248,6 +2251,9 @@ fi
 #
 #
 %changelog
+* Wed Jul 26 2017 Justin M. Forbes <jforbes@fedoraproject.org>
+- Fix mtx (rhbz 1471302)
+
 * Tue Jul 25 2017 Justin M. Forbes <jforbes@fedoraproject.org>
 - Force python3 for kvm_stat because we can't dep (rhbz 1456722)