From 5c43bb2484414b37115dac56dc76f1ecf4c05837 Mon Sep 17 00:00:00 2001 From: Adam Jackson Date: Mon, 10 Nov 2014 12:13:36 -0500 Subject: glx: Be more paranoid about variable-length requests [CVE-2014-8093 1/6] (v2) If the size computation routine returns -1 we should just reject the request outright. Clamping it to zero could give an attacker the opportunity to also mangle cmdlen in such a way that the subsequent length check passes, and the request would get executed, thus passing data we wanted to reject to the renderer. v3: backport to nx-libs 3.6.x (Mike DePaulo) v2: backport to RHEL5 - fix swap paths Reviewed-by: Keith Packard Reviewed-by: Julien Cristau Reviewed-by: Michal Srb Reviewed-by: Andy Ritger Signed-off-by: Adam Jackson Signed-off-by: Alan Coopersmith Signed-off-by: Fedora X Ninjas Signed-off-by: Dave Airlie fixup swaps --- nx-X11/programs/Xserver/GL/glx/glxcmds.c | 4 ++-- nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/nx-X11/programs/Xserver/GL/glx/glxcmds.c b/nx-X11/programs/Xserver/GL/glx/glxcmds.c index ca5eee82a..02f3ba7f2 100644 --- a/nx-X11/programs/Xserver/GL/glx/glxcmds.c +++ b/nx-X11/programs/Xserver/GL/glx/glxcmds.c @@ -1484,7 +1484,7 @@ int __glXRender(__GLXclientState *cl, GLbyte *pc) /* variable size command */ extra = (*entry->varsize)(pc + __GLX_RENDER_HDR_SIZE, False); if (extra < 0) { - extra = 0; + return BadLength; } if (cmdlen != __GLX_PAD(entry->bytes + extra)) { return BadLength; @@ -1601,7 +1601,7 @@ int __glXRenderLarge(__GLXclientState *cl, GLbyte *pc) */ extra = (*entry->varsize)(pc + __GLX_RENDER_LARGE_HDR_SIZE, False); if (extra < 0) { - extra = 0; + return BadLength; } /* large command's header is 4 bytes longer, so add 4 */ if (cmdlen != __GLX_PAD(entry->bytes + 4 + extra)) { diff --git a/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c b/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c index 595e814e5..027cba709 100644 --- a/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c +++ b/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c @@ -535,7 +535,7 @@ int __glXSwapRender(__GLXclientState *cl, GLbyte *pc) /* variable size command */ extra = (*entry->varsize)(pc + __GLX_RENDER_HDR_SIZE, True); if (extra < 0) { - extra = 0; + return BadLength; } if (cmdlen != __GLX_PAD(entry->bytes + extra)) { return BadLength; @@ -659,7 +659,7 @@ int __glXSwapRenderLarge(__GLXclientState *cl, GLbyte *pc) */ extra = (*entry->varsize)(pc + __GLX_RENDER_LARGE_HDR_SIZE, True); if (extra < 0) { - extra = 0; + return BadLength; } /* large command's header is 4 bytes longer, so add 4 */ if (cmdlen != __GLX_PAD(entry->bytes + 4 + extra)) { -- cgit v1.2.3