Fix most of clang -Wcast-align compilation warnings

Unlike gcc, clang is not smart enough to infer the alignment
of structure fields, so add some alignment hints to the code.

* libpam/include/pam_cc_compat.h (PAM_ATTRIBUTE_ALIGNED): New macro.
* modules/pam_namespace/md5.h: Include "pam_cc_compat.h".
(struct MD5Context): Add PAM_ATTRIBUTE_ALIGNED to "in" field.
* modules/pam_namespace/md5.c [!(__i386__ || __x86_64__)]
(uint8_aligned): New type.
[!(__i386__ || __x86_64__)] (byteReverse): Use it instead of
unsigned char.
* modules/pam_timestamp/sha1.h: Include "pam_cc_compat.h".
(struct sha1_context): Add PAM_ATTRIBUTE_ALIGNED to pending field.
* modules/pam_unix/md5.h: Include "pam_cc_compat.h".
(struct MD5Context): Add PAM_ATTRIBUTE_ALIGNED to "in" field.
* modules/pam_unix/md5.c [!HIGHFIRST] (uint8_aligned): New type.
[!HIGHFIRST] (byteReverse): Use it instead of unsigned char.

5 files changed, 17 insertions, 7 deletions

diff --git a/modules/pam_namespace/md5.c b/modules/pam_namespace/md5.c
index dc95ab14..b9a7f084 100644
--- a/modules/pam_namespace/md5.c
+++ b/modules/pam_namespace/md5.c
@@ -26,12 +26,14 @@
 #if defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__)
 #define byteReverse(buf, len)	/* Nothing */
 #else
-static void byteReverse(unsigned char *buf, unsigned longs);
+typedef unsigned char PAM_ATTRIBUTE_ALIGNED(4) uint8_aligned;
+
+static void byteReverse(uint8_aligned *buf, unsigned longs);
 
 /*
  * Note: this code is harmless on little-endian machines.
  */
-static void byteReverse(unsigned char *buf, unsigned longs)
+static void byteReverse(uint8_aligned *buf, unsigned longs)
 {
 	uint32 t;
 	do {
diff --git a/modules/pam_namespace/md5.h b/modules/pam_namespace/md5.h
index 73f85833..bded3302 100644
--- a/modules/pam_namespace/md5.h
+++ b/modules/pam_namespace/md5.h
@@ -2,12 +2,14 @@
 #ifndef MD5_H
 #define MD5_H
 
+#include "pam_cc_compat.h"
+
 typedef unsigned int uint32;
 
 struct MD5Context {
 	uint32 buf[4];
 	uint32 bits[2];
-	unsigned char in[64];
+	unsigned char in[64] PAM_ATTRIBUTE_ALIGNED(4);
 };
 
 #define MD5_DIGEST_LENGTH 16
diff --git a/modules/pam_timestamp/sha1.h b/modules/pam_timestamp/sha1.h
index a445e4e6..a1c38917 100644
--- a/modules/pam_timestamp/sha1.h
+++ b/modules/pam_timestamp/sha1.h
@@ -40,12 +40,13 @@
 
 #include <stdint.h>
 #include <sys/types.h>
+#include "pam_cc_compat.h"
 
 #define SHA1_BLOCK_SIZE 64
 
 struct sha1_context {
 	size_t count;
-	unsigned char pending[SHA1_BLOCK_SIZE];
+	unsigned char pending[SHA1_BLOCK_SIZE] PAM_ATTRIBUTE_ALIGNED(4);
 	uint32_t counts[2];
 	size_t pending_count;
 	uint32_t a, b, c, d, e;
diff --git a/modules/pam_unix/md5.c b/modules/pam_unix/md5.c
index 94f0485b..9954536f 100644
--- a/modules/pam_unix/md5.c
+++ b/modules/pam_unix/md5.c
@@ -24,13 +24,16 @@
 #ifndef HIGHFIRST
 #define byteReverse(buf, len)	/* Nothing */
 #else
-static void byteReverse(unsigned char *buf, unsigned longs);
+
+typedef unsigned char PAM_ATTRIBUTE_ALIGNED(4) uint8_aligned;
+
+static void byteReverse(uint8_aligned *buf, unsigned longs);
 
 #ifndef ASM_MD5
 /*
  * Note: this code is harmless on little-endian machines.
  */
-static void byteReverse(unsigned char *buf, unsigned longs)
+static void byteReverse(uint8_aligned *buf, unsigned longs)
 {
 	uint32 t;
 	do {
diff --git a/modules/pam_unix/md5.h b/modules/pam_unix/md5.h
index 103f168a..d9186b7f 100644
--- a/modules/pam_unix/md5.h
+++ b/modules/pam_unix/md5.h
@@ -2,12 +2,14 @@
 #ifndef MD5_H
 #define MD5_H
 
+#include "pam_cc_compat.h"
+
 typedef unsigned int uint32;
 
 struct MD5Context {
 	uint32 buf[4];
 	uint32 bits[2];
-	unsigned char in[64];
+	unsigned char in[64] PAM_ATTRIBUTE_ALIGNED(4);
 };
 
 void GoodMD5Init(struct MD5Context *);