On Thu, Nov 03, 2016 at 08:17:51AM -0700, Christoph Hellwig wrote: > On Fri, Oct 14, 2016 at 09:38:21AM +0200, Johannes Thumshirn wrote: > > On Thu, Oct 13, 2016 at 05:55:11PM +0200, Steffen Maier wrote: > > > Hm, still behaves for me like I reported for v2: > > > http://marc.info/?l=linux-scsi&m=147637177902937&w=2 > > > > Hi Steffen, > > > > Can you please try the following on top of 2/16? > > How does this fit into the patch we're replying to? Sorry but I don't quite get you. If you look at a mixed source assembly listing for fc_host_dispatch() [1] we load the the offset of 24 from %r12 into %r1 and then the beginning of %r1 into %r2 and crash. So if we now check if job->request_len is smaller than uint32_t we know we can't have a messagecode in the request and bail out early, instead of accessing a possible NULL pointer. At least that's my analysis, feel free to correct me if I'm wrong. [1] Listing: static int fc_bsg_host_dispatch(struct Scsi_Host *shost, struct bsg_job *job) { struct fc_internal *i = to_fc_internal(shost->transportt); struct fc_bsg_request *bsg_request = job->request; 5d54: e3 10 c0 18 00 04 lg %r1,24(%r12) struct fc_bsg_reply *bsg_reply = job->reply; 5d5a: e3 b0 c0 20 00 04 lg %r11,32(%r12) int cmdlen = sizeof(uint32_t); /* start with length of msgcode */ int ret; /* check if we really have all the request data needed */ if (job->request_len < cmdlen) { 5d60: a7 c4 00 48 jle 5df0 <fc_bsg_dispatch+0x1f0> ret = -ENOMSG; goto fail_host_msg; } /* Validate the host command */ switch (bsg_request->msgcode) { 5d64: 58 20 10 00 l %r2,0(%r1) 5d68: c2 2f 80 00 00 03 clfi %r2,2147483651 5d6e: a7 84 00 1a je 5da2 <fc_bsg_dispatch+0x1a2> 5d72: a7 24 00 0a jh 5d86 <fc_bsg_dispatch+0x186> 5d76: c0 19 80 00 00 01 iilf %r1,2147483649 5d7c: ec 21 00 2b a0 77 clrj %r2,%r1,10,5dd2 <fc_bsg_dispatch+0x1d2> 5d82: a7 f4 00 3b j 5df8 <fc_bsg_dispatch+0x1f8> 5d86: c0 59 80 00 00 04 iilf %r5,2147483652 5d8c: ec 25 00 0b 80 76 crj %r2,%r5,8,5da2 <fc_bsg_dispatch+0x1a2> 5d92: c0 59 80 00 00 ff iilf %r5,2147483903 5d98: ec 25 00 13 80 76 crj %r2,%r5,8,5dbe <fc_bsg_dispatch+0x1be> 5d9e: a7 f4 00 2d j 5df8 <fc_bsg_dispatch+0x1f8> Thanks, Johannes -- Johannes Thumshirn Storage jthumshirn@xxxxxxx +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 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
