s3/loadparm: ensure default service options are not changed

Rename sDefault to _sDefault and make it const. sDefault is make a copy
of _sDefault in in the initialisation function lp_load_ex().

As we may end up in setup_lp_context() without going through
lp_load_ex(), sDefault may still be uninitialized at that point, so I'm
initializing lp_ctx->sDefault from _sDefault.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=13051

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index 433727b3f7982ff9f6b51d7144938990a539ce4d..bb6b128604ea4ac7179ee930275544584c3495bb 100644 (file)
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -111,7 +111,7 @@ static bool defaults_saved = false;
 static struct loadparm_global Globals;
 
 /* This is a default service used to prime a services structure */
-static struct loadparm_service sDefault =
+static const struct loadparm_service _sDefault =
 {
        .valid = true,
        .autoloaded = false,
@@ -249,6 +249,12 @@ static struct loadparm_service sDefault =
        .dummy = ""
 };
 
+/*
+ * This is a copy of the default service structure. Service options in the
+ * global section would otherwise overwrite the initial default values.
+ */
+static struct loadparm_service sDefault;
+
 /* local variables */
 static struct loadparm_service **ServicePtrs = NULL;
 static int iNumServices = 0;
@@ -975,7 +981,7 @@ static struct loadparm_context *setup_lp_context(TALLOC_CTX *mem_ctx)
                return NULL;
        }
 
-       *lp_ctx->sDefault = sDefault;
+       *lp_ctx->sDefault = _sDefault;
        lp_ctx->services = NULL; /* We do not want to access this directly */
        lp_ctx->bInGlobalSection = bInGlobalSection;
        lp_ctx->flags = flags_list;
@@ -3865,6 +3871,7 @@ static bool lp_load_ex(const char *pszFname,
        bInGlobalSection = true;
        bGlobalOnly = global_only;
        bAllowIncludeRegistry = allow_include_registry;
+       sDefault = _sDefault;
 
        lp_ctx = setup_lp_context(talloc_tos());