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authorVasily Averin <vvs@virtuozzo.com>2018-12-24 14:44:52 +0300
committerJ. Bruce Fields <bfields@redhat.com>2018-12-27 21:00:58 -0500
commitd4b09acf924b84bae77cad090a9d108e70b43643 (patch)
treea5d2cc482f5aadfa509c83d61abf883366feb787 /include/trace
parentb8be5674fa9a6f3677865ea93f7803c4212f3e10 (diff)
sunrpc: use-after-free in svc_process_common()
if node have NFSv41+ mounts inside several net namespaces it can lead to use-after-free in svc_process_common() svc_process_common() /* Setup reply header */ rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE svc_process_common() can use incorrect rqstp->rq_xprt, its caller function bc_svc_process() takes it from serv->sv_bc_xprt. The problem is that serv is global structure but sv_bc_xprt is assigned per-netnamespace. According to Trond, the whole "let's set up rqstp->rq_xprt for the back channel" is nothing but a giant hack in order to work around the fact that svc_process_common() uses it to find the xpt_ops, and perform a couple of (meaningless for the back channel) tests of xpt_flags. All we really need in svc_process_common() is to be able to run rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr() Bruce J Fields points that this xpo_prep_reply_hdr() call is an awfully roundabout way just to do "svc_putnl(resv, 0);" in the tcp case. This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(), now it calls svc_process_common() with rqstp->rq_xprt = NULL. To adjust reply header svc_process_common() just check rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case. To handle rqstp->rq_xprt = NULL case in functions called from svc_process_common() patch intruduces net namespace pointer svc_rqst->rq_bc_net and adjust SVC_NET() definition. Some other function was also adopted to properly handle described case. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Cc: stable@vger.kernel.org Fixes: 23c20ecd4475 ("NFS: callback up - users counting cleanup") Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/sunrpc.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 28e384186c35..8617f4fd6b70 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -569,7 +569,8 @@ TRACE_EVENT(svc_process,
__field(u32, vers)
__field(u32, proc)
__string(service, name)
- __string(addr, rqst->rq_xprt->xpt_remotebuf)
+ __string(addr, rqst->rq_xprt ?
+ rqst->rq_xprt->xpt_remotebuf : "(null)")
),
TP_fast_assign(
@@ -577,7 +578,8 @@ TRACE_EVENT(svc_process,
__entry->vers = rqst->rq_vers;
__entry->proc = rqst->rq_proc;
__assign_str(service, name);
- __assign_str(addr, rqst->rq_xprt->xpt_remotebuf);
+ __assign_str(addr, rqst->rq_xprt ?
+ rqst->rq_xprt->xpt_remotebuf : "(null)");
),
TP_printk("addr=%s xid=0x%08x service=%s vers=%u proc=%u",