From d13a8ea18f852e97201269e55255a14fe4fe5d0f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Mon, 30 Jan 2023 17:36:57 +0100
Subject: Enable format compiler warnings

* libpam/include/pam_cc_compat.h (DIAG_PUSH_IGNORE_FORMAT_NONLITERAL,
DIAG_POP_IGNORE_FORMAT_NONLITERAL): New macros.
* libpam/pam_handlers.c (_pam_open_config_file): Use them to exempt
usage of format string literals from a constant array.
* m4/warn_lang_flags.m4 (gl_WARN_ADD): Add -Wformat=2.
---
 libpam/include/pam_cc_compat.h | 20 ++++++++++++++++----
 libpam/pam_handlers.c          |  6 ++++--
 m4/warn_lang_flags.m4          |  1 +
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/libpam/include/pam_cc_compat.h b/libpam/include/pam_cc_compat.h
index 69190368..0a6e32d5 100644
--- a/libpam/include/pam_cc_compat.h
+++ b/libpam/include/pam_cc_compat.h
@@ -32,6 +32,11 @@
 	_Pragma("GCC diagnostic ignored \"-Wcast-align\"")
 # define DIAG_POP_IGNORE_CAST_ALIGN					\
 	_Pragma("GCC diagnostic pop")
+# define DIAG_PUSH_IGNORE_FORMAT_NONLITERAL				\
+	_Pragma("GCC diagnostic push");					\
+	_Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
+# define DIAG_POP_IGNORE_FORMAT_NONLITERAL				\
+	_Pragma("GCC diagnostic pop")
 #elif PAM_CLANG_PREREQ(2, 6)
 # define DIAG_PUSH_IGNORE_CAST_QUAL					\
 	_Pragma("clang diagnostic push");				\
@@ -43,11 +48,18 @@
 	_Pragma("clang diagnostic ignored \"-Wcast-align\"")
 # define DIAG_POP_IGNORE_CAST_ALIGN					\
 	_Pragma("clang diagnostic pop")
+# define DIAG_PUSH_IGNORE_FORMAT_NONLITERAL				\
+	_Pragma("clang diagnostic push");				\
+	_Pragma("clang diagnostic ignored \"-Wformat-nonliteral\"")
+# define DIAG_POP_IGNORE_FORMAT_NONLITERAL				\
+	_Pragma("clang diagnostic pop")
 #else
-# define DIAG_PUSH_IGNORE_CAST_QUAL	/* empty */
-# define DIAG_POP_IGNORE_CAST_QUAL	/* empty */
-# define DIAG_PUSH_IGNORE_CAST_ALIGN	/* empty */
-# define DIAG_POP_IGNORE_CAST_ALIGN	/* empty */
+# define DIAG_PUSH_IGNORE_CAST_QUAL		/* empty */
+# define DIAG_POP_IGNORE_CAST_QUAL		/* empty */
+# define DIAG_PUSH_IGNORE_CAST_ALIGN		/* empty */
+# define DIAG_POP_IGNORE_CAST_ALIGN		/* empty */
+# define DIAG_PUSH_IGNORE_FORMAT_NONLITERAL	/* empty */
+# define DIAG_POP_IGNORE_FORMAT_NONLITERAL	/* empty */
 #endif
 
 /*
diff --git a/libpam/pam_handlers.c b/libpam/pam_handlers.c
index 12ebb8fc..6629480e 100644
--- a/libpam/pam_handlers.c
+++ b/libpam/pam_handlers.c
@@ -281,7 +281,7 @@ _pam_open_config_file(pam_handle_t *pamh
 			, char **path
 			, FILE **file)
 {
-    const char *pamd_dirs[] = { PAM_CONFIG_DF, PAM_CONFIG_DIST_DF
+    const char *const pamd_dirs[] = { PAM_CONFIG_DF, PAM_CONFIG_DIST_DF
 #ifdef VENDORDIR
                                , PAM_CONFIG_DIST2_DF
 #endif
@@ -317,10 +317,12 @@ _pam_open_config_file(pam_handle_t *pamh
     }
 
     for (i = 0; i < PAM_ARRAY_SIZE(pamd_dirs); i++) {
-        if (asprintf (&p, pamd_dirs[i], service) < 0) {
+	DIAG_PUSH_IGNORE_FORMAT_NONLITERAL
+	if (asprintf (&p, pamd_dirs[i], service) < 0) {
 	    pam_syslog(pamh, LOG_CRIT, "asprintf failed");
 	    return PAM_BUF_ERR;
 	}
+	DIAG_POP_IGNORE_FORMAT_NONLITERAL
 
 	D(("opening %s", p));
 	f = fopen(p, "r");
diff --git a/m4/warn_lang_flags.m4 b/m4/warn_lang_flags.m4
index 3ae03274..a4d6022f 100644
--- a/m4/warn_lang_flags.m4
+++ b/m4/warn_lang_flags.m4
@@ -8,6 +8,7 @@ gl_WARN_ADD([-Wcast-align])
 gl_WARN_ADD([-Wcast-align=strict])
 gl_WARN_ADD([-Wcast-qual])
 gl_WARN_ADD([-Wdeprecated])
+gl_WARN_ADD([-Wformat=2])
 gl_WARN_ADD([-Winit-self])
 gl_WARN_ADD([-Winline])
 gl_WARN_ADD([-Wmain])
-- 
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