make sure the shm cache entry size is a multiple of 8 bytes

see #1067; thanks @sanzinger

Signed-off-by: Hans Zandbelt <[email protected]>

ChangeLog

@@ -1,6 +1,7 @@
 12/28/2023
 - set memory alignment of shm cache structs to 64 bytes; see #1067
   should fix running on Raspberry PI / ARMv7 32 bits (arm32v7)
+- make sure the shm cache entry size is a multiple of 8 bytes, see #1067; thanks @sanzinger
 - bump to 2.4.15rc13
 
 12/22/2023

auth_openidc.conf

@@ -635,11 +635,12 @@
 # OIDCCacheShmMax <number>
 
 # When using OIDCCacheType "shm":
-# Specifies the maximum size for a single cache entry in bytes with a minimum of 8464 bytes.
+# Specifies the maximum size for a single cache entry in bytes with a minimum of 8736 bytes.
+# The value must a multiple of 8 bytes.
 # When caching large values such as numbers of attributes in a session or large metadata documents the 
 # entry size limit may be overrun, in which case errors will be displayed in the error.log
 # and the OIDCCacheShmEntrySizeMax value has to be increased.
-# When not specified, a default entry size of 16913 bytes (16384 value + 512 key + 17 overhead) is used.
+# When not specified, a default entry size of 16928 bytes (16384 value + 512 key + 32 overhead) is used.
 # OIDCCacheShmEntrySizeMax <bytes>
 
 # When using OIDCCacheType "file":

src/config.c

@@ -116,7 +116,7 @@
 /* default max cache size for shm */
 #define OIDC_DEFAULT_CACHE_SHM_SIZE 10000
 /* default max cache entry size for shm: # value + # key + # overhead */
-#define OIDC_DEFAULT_CACHE_SHM_ENTRY_SIZE_MAX 16384 + 512 + 17
+#define OIDC_DEFAULT_CACHE_SHM_ENTRY_SIZE_MAX 16384 + 512 + 32
 /* for issued-at timestamp (iat) checking */
 #define OIDC_DEFAULT_IDTOKEN_IAT_SLACK 600
 /* for file-based caching: clean interval in seconds */

src/parse.c

@@ -331,16 +331,19 @@ const char *oidc_parse_session_type(apr_pool_t *pool, const char *arg, int *type
 }
 
 /* minimum size of a SHM cache entry */
-#define OIDC_MINIMUM_CACHE_SHM_ENTRY_SIZE_MAX 8192 + 512 + 17 // 8Kb plus overhead
+#define OIDC_MINIMUM_CACHE_SHM_ENTRY_SIZE_MAX 8192 + 512 + 32 // 8Kb plus overhead
 /* maximum size of a SHM cache entry */
 #define OIDC_MAXIMUM_CACHE_SHM_ENTRY_SIZE_MAX 1024 * 1024 // 1Mb incl. overhead
 
 /*
  * parse the slot size of a SHM cache entry
  */
 const char *oidc_parse_cache_shm_entry_size_max(apr_pool_t *pool, const char *arg, int *int_value) {
-	return oidc_parse_int_min_max(pool, arg, int_value, OIDC_MINIMUM_CACHE_SHM_ENTRY_SIZE_MAX,
-				      OIDC_MAXIMUM_CACHE_SHM_ENTRY_SIZE_MAX);
+	const char *rv = oidc_parse_int_min_max(pool, arg, int_value, OIDC_MINIMUM_CACHE_SHM_ENTRY_SIZE_MAX,
+						OIDC_MAXIMUM_CACHE_SHM_ENTRY_SIZE_MAX);
+	if ((rv == NULL) && (((*int_value) % 8) != 0))
+		rv = "the slot size must be a multiple of 8";
+	return rv;
 }
 
 /*