From 37e7fb1f64b29ef06ec4d69ab0b7afa99c613383 Mon Sep 17 00:00:00 2001 From: Alan Coopersmith Date: Fri, 17 Jan 2014 18:54:03 -0800 Subject: [PATCH 18/40] unchecked malloc may allow unauthed client to crash Xserver [CVE-2014-8091] authdes_ezdecode() calls malloc() using a length provided by the connection handshake sent by a newly connected client in order to authenticate to the server, so should be treated as untrusted. It didn't check if malloc() failed before writing to the newly allocated buffer, so could lead to a server crash if the server fails to allocate memory (up to UINT16_MAX bytes, since the len field is a CARD16 in the X protocol). Reported-by: Ilja Van Sprundel Signed-off-by: Alan Coopersmith Reviewed-by: Peter Hutterer Conflicts: os/rpcauth.c --- nx-X11/programs/Xserver/os/rpcauth.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/nx-X11/programs/Xserver/os/rpcauth.c b/nx-X11/programs/Xserver/os/rpcauth.c index 3c5cb59..a12931e 100644 --- a/nx-X11/programs/Xserver/os/rpcauth.c +++ b/nx-X11/programs/Xserver/os/rpcauth.c @@ -78,6 +78,10 @@ authdes_ezdecode(char *inmsg, int len) SVCXPRT xprt; temp_inmsg = (char *) xalloc(len); + if (temp_inmsg == NULL) { + why = AUTH_FAILED; /* generic error, since there is no AUTH_BADALLOC */ + return NULL; + } memmove(temp_inmsg, inmsg, len); memset((char *)&msg, 0, sizeof(msg)); -- 2.1.4