Fix race in astdb

The underlying db1 implementation does not fully isolate the pages retrieved
from astdb, so the lock protecting accesses needs to be extended until the
copy from the shared memory structure is done.
(closes issue #14682)
 Reported by: makoto


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@182449 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 6 insertions, 3 deletions

diff --git a/main/db.c b/main/db.c
index 3e61be509..9da3a11dd 100644
--- a/main/db.c
+++ b/main/db.c
@@ -187,10 +187,8 @@ int ast_db_get(const char *family, const char *keys, char *value, int valuelen)
 	memset(value, 0, valuelen);
 	key.data = fullkey;
 	key.size = fullkeylen + 1;
-	
+
 	res = astdb->get(astdb, &key, &data, 0);
-	
-	ast_mutex_unlock(&dblock);
 
 	/* Be sure to NULL terminate our data either way */
 	if (res) {
@@ -208,6 +206,11 @@ int ast_db_get(const char *family, const char *keys, char *value, int valuelen)
 			ast_log(LOG_NOTICE, "Strange, empty value for /%s/%s\n", family, keys);
 		}
 	}
+
+	/* Data is not fully isolated for concurrency, so the lock must be extended
+	 * to after the copy to the output buffer. */
+	ast_mutex_unlock(&dblock);
+
 	return res;
 }