[Mesa-dev] [PATCH v3] intel/decoder: fix the possible out of bounds group_iter

[asimiklit.work at gmail.com]

From: Andrii Simiklit <andrii.simiklit at globallogic.com>

The "gen_group_get_length" function can return a negative value
and it can lead to the out of bounds group_iter.

v2: printing of "unknown command type" was added
v3: just the asserts are added

Signed-off-by: Andrii Simiklit <andrii.simiklit at globallogic.com>
---
 src/intel/common/gen_decoder.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/intel/common/gen_decoder.c b/src/intel/common/gen_decoder.c
index ec0a486..2d9609a 100644
--- a/src/intel/common/gen_decoder.c
+++ b/src/intel/common/gen_decoder.c
@@ -803,8 +803,10 @@ static bool
 iter_more_groups(const struct gen_field_iterator *iter)
 {
    if (iter->group->variable) {
+      int length = gen_group_get_length(iter->group, iter->p);
+      assert(length >= 0 && "error the length is unknown!");
       return iter_group_offset_bits(iter, iter->group_iter + 1) <
-              (gen_group_get_length(iter->group, iter->p) * 32);
+              (length * 32);
    } else {
       return (iter->group_iter + 1) < iter->group->group_count ||
          iter->group->next != NULL;
@@ -991,6 +993,7 @@ gen_field_iterator_init(struct gen_field_iterator *iter,
    iter->p_bit = p_bit;
 
    int length = gen_group_get_length(iter->group, iter->p);
+   assert(length >= 0 && "error the length is unknown!");
    iter->p_end = length > 0 ? &p[length] : NULL;
    iter->print_colors = print_colors;
 }
-- 
2.7.4