diff options
| author | Waldemar Brodkorb <wbx@uclibc-ng.org> | 2016-08-05 21:33:44 +0200 |
|---|---|---|
| committer | Waldemar Brodkorb <wbx@uclibc-ng.org> | 2016-08-05 21:33:44 +0200 |
| commit | 9213ad631513d0e67d9d31465c9cdb3f3dde0399 (patch) | |
| tree | 046479bb8e8b66192c8227f2054e3260e3dcd483 | |
| parent | 79dc2c282b655adb8d5075d9eb2519883042ccf8 (diff) | |
sunrpc: Do not use alloca in clntudp_call
CVE-2016-4429:
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).
From GNU libc:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;h=bc779a1a5b3035133024b21e2f339fe4219fb11c
| -rw-r--r-- | libc/inet/rpc/clnt_udp.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/libc/inet/rpc/clnt_udp.c b/libc/inet/rpc/clnt_udp.c index 4fc55b732..ce7e9e6d9 100644 --- a/libc/inet/rpc/clnt_udp.c +++ b/libc/inet/rpc/clnt_udp.c @@ -368,9 +368,15 @@ 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; @@ -395,10 +401,12 @@ 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 |