Re: [PATCH v3 02/16] scsi: don't use fc_bsg_job::request and fc_bsg_job::reply directly

From: Johannes Thumshirn
Date: Fri Oct 14 2016 - 03:38:42 EST


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?

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 4149dac..baebaab 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3786,6 +3786,12 @@ enum fc_dispatch_result {
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) {
+ ret = -ENOMSG;
+ goto fail_host_msg;
+ }
+
/* Validate the host command */
switch (bsg_request->msgcode) {
case FC_BSG_HST_ADD_RPORT:
@@ -3831,12 +3837,6 @@ enum fc_dispatch_result {
goto fail_host_msg;
}

- /* check if we really have all the request data needed */
- if (job->request_len < cmdlen) {
- ret = -ENOMSG;
- goto fail_host_msg;
- }
-
ret = i->f->bsg_request(job);
if (!ret)
return FC_DISPATCH_UNLOCKED;
@@ -3887,6 +3887,12 @@ enum fc_dispatch_result {
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) {
+ ret = -ENOMSG;
+ goto fail_rport_msg;
+ }
+
/* Validate the rport command */
switch (bsg_request->msgcode) {
case FC_BSG_RPT_ELS:



The rational behind this is, in fc_req_to_bsgjob() we're assigning
job->request as req->cmd and job->request_len = req->cmd_len. But without
checkinf job->request_len we don't know whether we're save to touch
job->request (a.k.a. bsg_request).

In the meanwhile I try to reproduce your report here.

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