Fix -Wcast-align compilation warnings on arm

Apparently, gcc is also not smart enough to infer the alignment
of structure fields, for details see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89133

Use unions to avoid these casts altogether, this fixes compilation
warnings reported by gcc on arm, e.g.:

md5.c: In function 'MD5Update':
md5.c:92:35: error: cast increases required alignment of target type [-Werror=cast-align]
   92 |   MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
      |                                   ^
md5.c:101:35: error: cast increases required alignment of target type [-Werror=cast-align]
  101 |   MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
      |                                   ^
md5.c: In function 'MD5Final':
md5.c:136:35: error: cast increases required alignment of target type [-Werror=cast-align]
  136 |   MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
      |                                   ^
md5.c:147:9: error: cast increases required alignment of target type [-Werror=cast-align]
  147 |  memcpy((uint32 *)ctx->in + 14, ctx->bits, 2*sizeof(uint32));
      |         ^
md5.c:149:34: error: cast increases required alignment of target type [-Werror=cast-align]
  149 |  MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
      |                                  ^

* modules/pam_namespace/md5.h (struct MD5Context): Replace "buf" and
"in" fields with unions.  All users updated.
* modules/pam_unix/md5.h (struct MD5Context): Likewise.
* modules/pam_timestamp/sha1.h (struct sha1_context.pending): Replace
with a union.  All users updated.

Complements: v1.4.0~195 ("Fix most of clang -Wcast-align compilation warnings")

2 files changed, 28 insertions, 22 deletions

diff --git a/modules/pam_namespace/md5.c b/modules/pam_namespace/md5.c
index 4f83f7f0..22e41ee0 100644
--- a/modules/pam_namespace/md5.c
+++ b/modules/pam_namespace/md5.c
@@ -51,10 +51,10 @@ static void byteReverse(uint8_aligned *buf, unsigned longs)
  */
 void MD5Name(MD5Init)(struct MD5Context *ctx)
 {
-	ctx->buf[0] = 0x67452301U;
-	ctx->buf[1] = 0xefcdab89U;
-	ctx->buf[2] = 0x98badcfeU;
-	ctx->buf[3] = 0x10325476U;
+	ctx->buf.i[0] = 0x67452301U;
+	ctx->buf.i[1] = 0xefcdab89U;
+	ctx->buf.i[2] = 0x98badcfeU;
+	ctx->buf.i[3] = 0x10325476U;
 
 	ctx->bits[0] = 0;
 	ctx->bits[1] = 0;
@@ -80,7 +80,7 @@ void MD5Name(MD5Update)(struct MD5Context *ctx, unsigned const char *buf, unsign
 	/* Handle any leading odd-sized chunks */
 
 	if (t) {
-		unsigned char *p = (unsigned char *) ctx->in + t;
+		unsigned char *p = ctx->in.c + t;
 
 		t = 64 - t;
 		if (len < t) {
@@ -88,24 +88,24 @@ void MD5Name(MD5Update)(struct MD5Context *ctx, unsigned const char *buf, unsign
 			return;
 		}
 		memcpy(p, buf, t);
-		byteReverse(ctx->in, 16);
-		MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
+		byteReverse(ctx->in.c, 16);
+		MD5Name(MD5Transform)(ctx->buf.i, ctx->in.i);
 		buf += t;
 		len -= t;
 	}
 	/* Process data in 64-byte chunks */
 
 	while (len >= 64) {
-		memcpy(ctx->in, buf, 64);
-		byteReverse(ctx->in, 16);
-		MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
+		memcpy(ctx->in.c, buf, 64);
+		byteReverse(ctx->in.c, 16);
+		MD5Name(MD5Transform)(ctx->buf.i, ctx->in.i);
 		buf += 64;
 		len -= 64;
 	}
 
 	/* Handle any remaining bytes of data. */
 
-	memcpy(ctx->in, buf, len);
+	memcpy(ctx->in.c, buf, len);
 }
 
 /*
@@ -122,7 +122,7 @@ void MD5Name(MD5Final)(unsigned char digest[16], struct MD5Context *ctx)
 
 	/* Set the first char of padding to 0x80.  This is safe since there is
 	   always at least one byte free */
-	p = ctx->in + count;
+	p = ctx->in.c + count;
 	*p++ = 0x80;
 
 	/* Bytes of padding needed to make 64 bytes */
@@ -132,23 +132,23 @@ void MD5Name(MD5Final)(unsigned char digest[16], struct MD5Context *ctx)
 	if (count < 8) {
 		/* Two lots of padding:  Pad the first block to 64 bytes */
 		memset(p, 0, count);
-		byteReverse(ctx->in, 16);
-		MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
+		byteReverse(ctx->in.c, 16);
+		MD5Name(MD5Transform)(ctx->buf.i, ctx->in.i);
 
 		/* Now fill the next block with 56 bytes */
-		memset(ctx->in, 0, 56);
+		memset(ctx->in.c, 0, 56);
 	} else {
 		/* Pad block to 56 bytes */
 		memset(p, 0, count - 8);
 	}
-	byteReverse(ctx->in, 14);
+	byteReverse(ctx->in.c, 14);
 
 	/* Append length in bits and transform */
-	memcpy((uint32 *)ctx->in + 14, ctx->bits, 2*sizeof(uint32));
+	memcpy(ctx->in.i + 14, ctx->bits, 2*sizeof(uint32));
 
-	MD5Name(MD5Transform)(ctx->buf, (uint32 *) ctx->in);
-	byteReverse((unsigned char *) ctx->buf, 4);
-	memcpy(digest, ctx->buf, 16);
+	MD5Name(MD5Transform)(ctx->buf.i, ctx->in.i);
+	byteReverse(ctx->buf.c, 4);
+	memcpy(digest, ctx->buf.c, 16);
 	memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }
 
diff --git a/modules/pam_namespace/md5.h b/modules/pam_namespace/md5.h
index bded3302..501aab4b 100644
--- a/modules/pam_namespace/md5.h
+++ b/modules/pam_namespace/md5.h
@@ -7,9 +7,15 @@
 typedef unsigned int uint32;
 
 struct MD5Context {
-	uint32 buf[4];
+	union {
+		uint32 i[4];
+		unsigned char c[16] PAM_ATTRIBUTE_ALIGNED(4);
+	} buf;
 	uint32 bits[2];
-	unsigned char in[64] PAM_ATTRIBUTE_ALIGNED(4);
+	union {
+		uint32 i[16];
+		unsigned char c[64] PAM_ATTRIBUTE_ALIGNED(4);
+	} in;
 };
 
 #define MD5_DIGEST_LENGTH 16