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authorFlorian Weimer <fweimer@redhat.com>2016-05-23 20:18:34 +0200
committerFlorian Weimer <fweimer@redhat.com>2016-05-23 20:18:34 +0200
commitbc779a1a5b3035133024b21e2f339fe4219fb11c (patch)
tree6c7b4ca874d7277de7a4f77d20f3013380ee79bf
parent3375cfafa7961c6ae0e509c31c3b3cef9ad1f03d (diff)
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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).
-rw-r--r--ChangeLog7
-rw-r--r--NEWS4
-rw-r--r--sunrpc/clnt_udp.c10
3 files changed, 20 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index 4455c6d..ab323b2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
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.
+
+2016-05-23 Florian Weimer <fweimer@redhat.com>
+
[BZ #20111]
* bits/sockaddr.h (_SS_SIZE): Define.
* bits/socket.h (_SS_SIZE): Remove.
diff --git a/NEWS b/NEWS
index b3fd3cc..2341697 100644
--- a/NEWS
+++ b/NEWS
@@ -48,6 +48,10 @@ 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:
[The release manager will add the list generated by
diff --git a/sunrpc/clnt_udp.c b/sunrpc/clnt_udp.c
index a6cf5f1..4d9acb1 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