diff options
| author | Vasily Averin <vvs@virtuozzo.com> | 2018-12-24 14:44:52 +0300 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2018-12-28 05:00:58 +0300 |
| commit | d4b09acf924b84bae77cad090a9d108e70b43643 (patch) | |
| tree | a5d2cc482f5aadfa509c83d61abf883366feb787 /net/sunrpc/svc.c | |
| parent | b8be5674fa9a6f3677865ea93f7803c4212f3e10 (diff) | |
| download | linux-d4b09acf924b84bae77cad090a9d108e70b43643.tar.xz | |
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 'net/sunrpc/svc.c')
| -rw-r--r-- | net/sunrpc/svc.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index d13e05f1a990..fb647bc01fc5 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1172,7 +1172,8 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv) clear_bit(RQ_DROPME, &rqstp->rq_flags); /* Setup reply header */ - rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); + if (rqstp->rq_prot == IPPROTO_TCP) + svc_tcp_prep_reply_hdr(rqstp); svc_putu32(resv, rqstp->rq_xid); @@ -1244,7 +1245,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv) * for lower versions. RPC_PROG_MISMATCH seems to be the closest * fit. */ - if (versp->vs_need_cong_ctrl && + if (versp->vs_need_cong_ctrl && rqstp->rq_xprt && !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags)) goto err_bad_vers; @@ -1336,7 +1337,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv) return 0; close: - if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) + if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) svc_close_xprt(rqstp->rq_xprt); dprintk("svc: svc_process close\n"); return 0; @@ -1459,10 +1460,10 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req, dprintk("svc: %s(%p)\n", __func__, req); /* Build the svc_rqst used by the common processing routine */ - rqstp->rq_xprt = serv->sv_bc_xprt; rqstp->rq_xid = req->rq_xid; rqstp->rq_prot = req->rq_xprt->prot; rqstp->rq_server = serv; + rqstp->rq_bc_net = req->rq_xprt->xprt_net; rqstp->rq_addrlen = sizeof(req->rq_xprt->addr); memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen); |