From 98dfd59a0445666060c97b0dccaf0e9f030b547a Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 30 May 2013 09:51:41 +1000 Subject: [PATCH] i965: fix problem with constant out of bounds access (v2) This is my attempt at fixing this as the CVE is making RH security team care enough to make me look at this. (please upstream, security fixes are more important than whatever else you are doing, if for no other reason than it saves me having to fix stuff I've no real clue about). Since Frank's original fix was denied, here is my attempt to just alias all constants that are out of bounds < 0 or > nr_params to constant 0, hopefully this provides the undefined behaviour idr requires.. CVE-2013-1872 v2: drop the last hunk which was a separate fix (now in master). hopefully fix the indentations. NOTE: This is a candidate for stable branches. Reviewed-by: Kenneth Graunke Signed-off-by: Dave Airlie --- src/mesa/drivers/dri/i965/brw_fs.cpp | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index baaa25c..9efdfc8 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -1504,7 +1504,13 @@ fs_visitor::remove_dead_constants() if (inst->src[i].file != UNIFORM) continue; - assert(constant_nr < (int)c->prog_data.nr_params); + /* if we get a negative constant nr or one greater than we can + * handle, this can cause an overflow, we can't just refuse to + * build, so just go undefined and alias everyone to constant 0. + */ + if (constant_nr < 0 || constant_nr >= (int)c->prog_data.nr_params) { + constant_nr = 0; + } /* For now, set this to non-negative. We'll give it the * actual new number in a moment, in order to keep the @@ -1552,6 +1558,10 @@ fs_visitor::remove_dead_constants() if (inst->src[i].file != UNIFORM) continue; + /* as above alias to 0 */ + if (constant_nr < 0 || constant_nr >= (int)c->prog_data.nr_params) { + constant_nr = 0; + } assert(this->params_remap[constant_nr] != -1); inst->src[i].reg = this->params_remap[constant_nr]; inst->src[i].reg_offset = 0; -- 2.7.4