CLEANUP: cache: use read_u32/write_u32 to access the cache entry's hash

Enabling strict aliasing fails on the cache's hash which is a series of
20 bytes cast as u32. And in practice it could even fail on some archs
if the http_txn didn't guarantee the hash was properly aligned. Let's
use read_u32() to read the value and write_u32() to set it, this makes
sure the compiler emits the correct code to access these and knows about
the intentional aliasing.

diff --git a/src/cache.c b/src/cache.c
index dc11cf5..b0be209 100644 (file)
--- a/src/cache.c
+++ b/src/cache.c
@@ -36,6 +36,7 @@
 #include <common/hash.h>
 #include <common/htx.h>
 #include <common/initcall.h>
+#include <common/net_helper.h>
 
 #define CACHE_FLT_F_IMPLICIT_DECL  0x00000001 /* The cache filtre was implicitly declared (ie without
                                               * the filter keyword) */
@@ -95,7 +96,7 @@ struct cache_entry *entry_exist(struct cache *cache, char *hash)
        struct eb32_node *node;
        struct cache_entry *entry;
 
-       node = eb32_lookup(&cache->entries, (*(unsigned int *)hash));
+       node = eb32_lookup(&cache->entries, read_u32(hash));
        if (!node)
                return NULL;
 
@@ -549,7 +550,7 @@ enum act_return http_action_store_cache(struct act_rule *rule, struct proxy *px,
        struct shared_context *shctx = shctx_ptr(cconf->c.cache);
        struct cache_st *cache_ctx = NULL;
        struct cache_entry *object, *old;
-       unsigned int key = *(unsigned int *)txn->cache_hash;
+       unsigned int key = read_u32(txn->cache_hash);
        struct htx *htx;
        struct http_hdr_ctx ctx;
        size_t hdrs_len = 0;
@@ -1530,7 +1531,7 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
                        }
 
                        entry = container_of(node, struct cache_entry, eb);
-                       chunk_printf(&trash, "%p hash:%u size:%u (%u blocks), refcount:%u, expire:%d\n", entry, (*(unsigned int *)entry->hash), block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
+                       chunk_printf(&trash, "%p hash:%u size:%u (%u blocks), refcount:%u, expire:%d\n", entry, read_u32(entry->hash), block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
 
                        next_key = node->key + 1;
                        appctx->ctx.cli.i0 = next_key;

diff --git a/src/http_ana.c b/src/http_ana.c
index b55e1bc..e3d2244 100644 (file)
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -14,6 +14,7 @@
 #include <common/config.h>
 #include <common/debug.h>
 #include <common/htx.h>
+#include <common/net_helper.h>
 #include <common/uri_auth.h>
 
 #include <types/capture.h>
@@ -5047,7 +5048,7 @@ void http_init_txn(struct stream *s)
                      : 0);
        txn->status = -1;
        txn->errmsg = NULL;
-       *(unsigned int *)txn->cache_hash = 0;
+       write_u32(txn->cache_hash, 0);
 
        txn->cookie_first_date = 0;
        txn->cookie_last_date = 0;