| commit 06f7ebb1dade2f0dbf872ea2bedf17cff4734bdd |
| Author: Olaf Kirch <okir@...e.de> |
| Date: Thu Aug 6 16:27:20 2015 +0200 |
| |
| Fix memory corruption in PMAP_CALLIT code |
| |
| - A PMAP_CALLIT call comes in on IPv4 UDP |
| - rpcbind duplicates the caller's address to a netbuf and stores it in |
| FINFO[0].caller_addr. caller_addr->buf now points to a memory region A |
| with a size of 16 bytes |
| - rpcbind forwards the call to the local service, receives a reply |
| - when processing the reply, it does this in xprt_set_caller: |
| xprt->xp_rtaddr = *FINFO[0].caller_addr |
| It sends out the reply, and then frees the netbuf caller_addr and |
| caller_addr.buf. |
| However, it does not clear xp_rtaddr, so xp_rtaddr.buf now refers |
| to memory region A, which is free. |
| - When the next call comes in on the UDP/IPv4 socket, svc_dg_recv will |
| be called, which will set xp_rtaddr to the client's address. |
| It will reuse the buffer inside xp_rtaddr, ie it will write a |
| sockaddr_in to region A |
| |
| Some time down the road, an incoming TCP connection is accepted, |
| allocating a fresh SVCXPRT. The memory region A is inside the |
| new SVCXPRT |
| |
| - While processing the TCP call, another UDP call comes in, again |
| overwriting region A with the client's address |
| - TCP client closes connection. In svc_destroy, we now trip over |
| the garbage left in region A |
| |
| We ran into the case where a commercial scanner was triggering |
| occasional rpcbind segfaults. The core file that was captured showed |
| a corrupted xprt->xp_netid pointer that was really a sockaddr_in. |
| |
| Signed-off-by: Olaf Kirch <okir@...e.de> |
| |
| Upstream-Status: Backport |
| |
| Signed-off-by: Li Zhou <li.zhou@windriver.com> |
| --- |
| src/rpcb_svc_com.c | 23 ++++++++++++++++++++++- |
| 1 file changed, 22 insertions(+), 1 deletion(-) |
| |
| Index: rpcbind-0.1.6+git20080930/src/rpcb_svc_com.c |
| =================================================================== |
| --- rpcbind-0.1.6+git20080930.orig/src/rpcb_svc_com.c |
| +++ rpcbind-0.1.6+git20080930/src/rpcb_svc_com.c |
| @@ -1298,12 +1298,33 @@ check_rmtcalls(struct pollfd *pfds, int |
| return (ncallbacks_found); |
| } |
| |
| +/* |
| + * This is really a helper function defined in libtirpc, but unfortunately, it hasn't |
| + * been exported yet. |
| + */ |
| +static struct netbuf * |
| +__rpc_set_netbuf(struct netbuf *nb, const void *ptr, size_t len) |
| +{ |
| + if (nb->len != len) { |
| + if (nb->len) |
| + mem_free(nb->buf, nb->len); |
| + nb->buf = mem_alloc(len); |
| + if (nb->buf == NULL) |
| + return NULL; |
| + |
| + nb->maxlen = nb->len = len; |
| + } |
| + memcpy(nb->buf, ptr, len); |
| + return nb; |
| +} |
| + |
| static void |
| xprt_set_caller(SVCXPRT *xprt, struct finfo *fi) |
| { |
| + const struct netbuf *caller = fi->caller_addr; |
| u_int32_t *xidp; |
| |
| - *(svc_getrpccaller(xprt)) = *(fi->caller_addr); |
| + __rpc_set_netbuf(svc_getrpccaller(xprt), caller->buf, caller->len); |
| xidp = __rpcb_get_dg_xidp(xprt); |
| *xidp = fi->caller_xid; |
| } |