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Fixed Seg fault in PMAP_CALLIT code (bz1264351)

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Signed-off-by: Steve Dickson <steved@redhat.com>
This commit is contained in:
Steve Dickson 2015-11-02 10:23:17 -05:00
parent dd1f5abd51
commit 258db20a41
2 changed files with 85 additions and 1 deletions
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77
rpcbind-0.2.3-pmap_callit.diff Normal file
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@ -0,0 +1,77 @@
commit d5dace219953c45d26ae42db238052b68540649a
Author: Olaf Kirch <okir@suse.de>
Date: Fri Oct 30 10:18:20 2015 -0400
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@suse.de>
Signed-off-by: Steve Dickson <steved@redhat.com>
diff --git a/src/rpcb_svc_com.c b/src/rpcb_svc_com.c
index ff9ce6b..4ae93f1 100644
--- a/src/rpcb_svc_com.c
+++ b/src/rpcb_svc_com.c
@@ -1183,12 +1183,33 @@ check_rmtcalls(struct pollfd *pfds, int nfds)
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;
}

9
rpcbind.spec
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@ -1,6 +1,6 @@
Name: rpcbind
Version: 0.2.3
Release: 0.3%{?dist}
Release: 0.4%{?dist}
Summary: Universal Addresses to RPC Program Number Mapper
Group: System Environment/Daemons
License: BSD
@ -21,6 +21,8 @@ Requires(post): chkconfig systemd
Requires(preun): systemd
Requires(postun): systemd coreutils
Patch001: rpcbind-0.2.3-pmap_callit.diff
Provides: portmap = %{version}-%{release}
Obsoletes: portmap <= 4.0-65.3
@ -32,6 +34,8 @@ RPC calls on a server on that machine.
%prep
%setup -q
%patch001 -p1
%build
%ifarch s390 s390x
PIE="-fPIE"
@ -121,6 +125,9 @@ fi
%{_unitdir}/rpcbind.socket
%changelog
* Mon Nov 2 2015 Steve Dickson <steved@redhat.com> - 0.2.3-0.4
- Fixed Seg fault in PMAP_CALLIT code (bz1264351)
* Sun Nov 01 2015 Kalev Lember <klember@redhat.com> - 0.2.3-0.3
- Rebuilt for libtirpc soname bump