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| author | Vasily Averin <vvs@virtuozzo.com> | 2018-12-24 14:44:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-16 22:16:12 +0100 |
| commit | 9615b6aeccbfb233fd672107aa6885bf039c3de3 (patch) | |
| tree | eeca274c8ddc354a01ca2169e57fadf974b55110 /include | |
| parent | 3897b4ae1fdc2cdc90594f817c69166855139c06 (diff) | |
| download | linux-stable-9615b6aeccbfb233fd672107aa6885bf039c3de3.tar.gz linux-stable-9615b6aeccbfb233fd672107aa6885bf039c3de3.tar.bz2 linux-stable-9615b6aeccbfb233fd672107aa6885bf039c3de3.zip | |
sunrpc: use-after-free in svc_process_common()
commit d4b09acf924b84bae77cad090a9d108e70b43643 upstream.
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>
v2: - added lost extern svc_tcp_prep_reply_hdr()
- dropped trace_svc_process() changes
- context fixes in svc_process_common()
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sunrpc/svc.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index cc0fc712bb82..a8ac3f25b4ec 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -290,9 +290,12 @@ struct svc_rqst { struct svc_cacherep * rq_cacherep; /* cache info */ struct task_struct *rq_task; /* service thread */ spinlock_t rq_lock; /* per-request lock */ + struct net *rq_bc_net; /* pointer to backchannel's + * net namespace + */ }; -#define SVC_NET(svc_rqst) (svc_rqst->rq_xprt->xpt_net) +#define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net) /* * Rigorous type checking on sockaddr type conversions |