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| author | Florian Weimer <fweimer@redhat.com> | 2016-05-23 20:18:34 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2016-05-24 11:16:07 +0200 |
| commit | bdce95930e1d9a7d013d1ba78740243491262879 (patch) | |
| tree | 1c1a697d937332c5a9b39961bea91cdbc969c71e | |
| parent | 25a34b0ac1356c1442380db2d2b13e05ccaeedd9 (diff) | |
| download | glibc-bdce95930e1d9a7d013d1ba78740243491262879.tar.gz | |
CVE-2016-4429: sunrpc: Do not use alloca in clntudp_call [BZ #20112]
The call is technically in a loop, and under certain circumstances
(which are quite difficult to reproduce in a test case), alloca
can be invoked repeatedly during a single call to clntudp_call.
As a result, the available stack space can be exhausted (even
though individual alloca sizes are bounded implicitly by what
can fit into a UDP packet, as a side effect of the earlier
successful send operation).
(cherry picked from commit bc779a1a5b3035133024b21e2f339fe4219fb11c)
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | NEWS | 4 | ||||
| -rw-r--r-- | sunrpc/clnt_udp.c | 10 |
3 files changed, 20 insertions, 1 deletions
@@ -1,3 +1,10 @@ +2016-05-23 Florian Weimer <fweimer@redhat.com> + + CVE-2016-4429 + [BZ #20112] + * sunrpc/clnt_udp.c (clntudp_call): Use malloc/free for the error + payload. + 2016-05-13 Florian Weimer <fweimer@redhat.com> Fix race condition in tst-mallocfork2, use fewer resources. @@ -18,6 +18,10 @@ Security related changes: called with the GLOB_ALTDIRFUNC flag and encountered a long file name. Reported by Alexander Cherepanov. (CVE-2016-1234) +* The Sun RPC UDP client could exhaust all available stack space when + flooded with crafted ICMP and UDP messages. Reported by Aldy Hernandez' + alloca plugin for GCC. (CVE-2016-4429) + The following bugs are resolved with this release: [19679] gcc-4.9.3 C++ exception handling broken due to unaligned stack diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c index a6cf5f1ca7..4d9acb1e6a 100644 --- a/sunrpc/clnt_udp.c +++ b/sunrpc/clnt_udp.c @@ -388,9 +388,15 @@ send_again: struct sock_extended_err *e; struct sockaddr_in err_addr; struct iovec iov; - char *cbuf = (char *) alloca (outlen + 256); + char *cbuf = malloc (outlen + 256); int ret; + if (cbuf == NULL) + { + cu->cu_error.re_errno = errno; + return (cu->cu_error.re_status = RPC_CANTRECV); + } + iov.iov_base = cbuf + 256; iov.iov_len = outlen; msg.msg_name = (void *) &err_addr; @@ -415,10 +421,12 @@ send_again: cmsg = CMSG_NXTHDR (&msg, cmsg)) if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR) { + free (cbuf); e = (struct sock_extended_err *) CMSG_DATA(cmsg); cu->cu_error.re_errno = e->ee_errno; return (cu->cu_error.re_status = RPC_CANTRECV); } + free (cbuf); } #endif do |