mesa: don't memcmp() off the end of a cache key.

Reported-by: `per` in #intel-gfx

The size of the cache key varies, so store the actual size as well as
the key blob itself, rather than just assuming it's the same as the size
passed in.

NOTE: This is a candidate for stable branches.

V2: Don't leave silly holes in structure; use unsigned instead of GLuint.
V3: Fix missing case for `last` match.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Paul Berry <stereotype441@gmail.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/src/mesa/program/prog_cache.c b/src/mesa/program/prog_cache.c
index 47f926b..1f1c614 100644
--- a/src/mesa/program/prog_cache.c
+++ b/src/mesa/program/prog_cache.c
@@ -37,6 +37,7 @@
 struct cache_item
 {
    GLuint hash;
+   unsigned keysize;
    void *key;
    struct gl_program *program;
    struct cache_item *next;
@@ -174,7 +175,8 @@ struct gl_program *
 _mesa_search_program_cache(struct gl_program_cache *cache,
                            const void *key, GLuint keysize)
 {
-   if (cache->last && 
+   if (cache->last &&
+       cache->last->keysize == keysize &&
        memcmp(cache->last->key, key, keysize) == 0) {
       return cache->last->program;
    }
@@ -183,7 +185,10 @@ _mesa_search_program_cache(struct gl_program_cache *cache,
       struct cache_item *c;
 
       for (c = cache->items[hash % cache->size]; c; c = c->next) {
-         if (c->hash == hash && memcmp(c->key, key, keysize) == 0) {
+         if (c->hash == hash &&
+             c->keysize == keysize &&
+             memcmp(c->key, key, keysize) == 0) {
+
             cache->last = c;
             return c->program;
          }
@@ -207,6 +212,7 @@ _mesa_program_cache_insert(struct gl_context *ctx,
 
    c->key = malloc(keysize);
    memcpy(c->key, key, keysize);
+   c->keysize = keysize;
 
    c->program = program;  /* no refcount change */
 
@@ -235,6 +241,7 @@ _mesa_shader_cache_insert(struct gl_context *ctx,
 
    c->key = malloc(keysize);
    memcpy(c->key, key, keysize);
+   c->keysize = keysize;
 
    c->program = (struct gl_program *)program;  /* no refcount change */