Avoid undefined behavior with unaligned accesses

Fixes: #4983

[extended tests]

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/6074)

7 files changed, 91 insertions, 36 deletions

diff --git a/crypto/modes/cbc128.c b/crypto/modes/cbc128.c
index eec44bd91a..ba765626ee 100644
--- a/crypto/modes/cbc128.c
+++ b/crypto/modes/cbc128.c
@@ -15,6 +15,12 @@
 # define STRICT_ALIGNMENT 0
 #endif
 
+#if defined(__GNUC__) && !STRICT_ALIGNMENT
+typedef size_t size_t_aX __attribute((__aligned__(1)));
+#else
+typedef size_t size_t_aX;
+#endif
+
 void CRYPTO_cbc128_encrypt(const unsigned char *in, unsigned char *out,
                            size_t len, const void *key,
                            unsigned char ivec[16], block128_f block)
@@ -40,8 +46,8 @@ void CRYPTO_cbc128_encrypt(const unsigned char *in, unsigned char *out,
     } else {
         while (len >= 16) {
             for (n = 0; n < 16; n += sizeof(size_t))
-                *(size_t *)(out + n) =
-                    *(size_t *)(in + n) ^ *(size_t *)(iv + n);
+                *(size_t_aX *)(out + n) =
+                    *(size_t_aX *)(in + n) ^ *(size_t_aX *)(iv + n);
             (*block) (out, out, key);
             iv = out;
             len -= 16;
@@ -96,7 +102,8 @@ void CRYPTO_cbc128_decrypt(const unsigned char *in, unsigned char *out,
             }
         } else if (16 % sizeof(size_t) == 0) { /* always true */
             while (len >= 16) {
-                size_t *out_t = (size_t *)out, *iv_t = (size_t *)iv;
+                size_t_aX *out_t = (size_t_aX *)out;
+                size_t_aX *iv_t = (size_t_aX *)iv;
 
                 (*block) (in, out, key);
                 for (n = 0; n < 16 / sizeof(size_t); n++)
@@ -125,8 +132,10 @@ void CRYPTO_cbc128_decrypt(const unsigned char *in, unsigned char *out,
             }
         } else if (16 % sizeof(size_t) == 0) { /* always true */
             while (len >= 16) {
-                size_t c, *out_t = (size_t *)out, *ivec_t = (size_t *)ivec;
-                const size_t *in_t = (const size_t *)in;
+                size_t c;
+                size_t_aX *out_t = (size_t_aX *)out;
+                size_t_aX *ivec_t = (size_t_aX *)ivec;
+                const size_t_aX *in_t = (const size_t_aX *)in;
 
                 (*block) (in, tmp.c, key);
                 for (n = 0; n < 16 / sizeof(size_t); n++) {
diff --git a/crypto/modes/ccm128.c b/crypto/modes/ccm128.c
index 1ffd6df46f..e1b2501273 100644
--- a/crypto/modes/ccm128.c
+++ b/crypto/modes/ccm128.c
@@ -11,6 +11,14 @@
 #include <openssl/crypto.h>
 #include "crypto/modes.h"
 
+#ifndef STRICT_ALIGNMENT
+# ifdef __GNUC__
+typedef u64 u64_a1 __attribute((__aligned__(1)));
+# else
+typedef u64 u64_a1;
+# endif
+#endif
+
 /*
  * First you setup M and L parameters and pass the key schedule. This is
  * called once per session setup...
@@ -170,8 +178,8 @@ int CRYPTO_ccm128_encrypt(CCM128_CONTEXT *ctx,
         ctx->cmac.u[0] ^= temp.u[0];
         ctx->cmac.u[1] ^= temp.u[1];
 #else
-        ctx->cmac.u[0] ^= ((u64 *)inp)[0];
-        ctx->cmac.u[1] ^= ((u64 *)inp)[1];
+        ctx->cmac.u[0] ^= ((u64_a1 *)inp)[0];
+        ctx->cmac.u[1] ^= ((u64_a1 *)inp)[1];
 #endif
         (*block) (ctx->cmac.c, ctx->cmac.c, key);
         (*block) (ctx->nonce.c, scratch.c, key);
@@ -181,8 +189,8 @@ int CRYPTO_ccm128_encrypt(CCM128_CONTEXT *ctx,
         temp.u[1] ^= scratch.u[1];
         memcpy(out, temp.c, 16);
 #else
-        ((u64 *)out)[0] = scratch.u[0] ^ ((u64 *)inp)[0];
-        ((u64 *)out)[1] = scratch.u[1] ^ ((u64 *)inp)[1];
+        ((u64_a1 *)out)[0] = scratch.u[0] ^ ((u64_a1 *)inp)[0];
+        ((u64_a1 *)out)[1] = scratch.u[1] ^ ((u64_a1 *)inp)[1];
 #endif
         inp += 16;
         out += 16;
@@ -254,8 +262,10 @@ int CRYPTO_ccm128_decrypt(CCM128_CONTEXT *ctx,
         ctx->cmac.u[1] ^= (scratch.u[1] ^= temp.u[1]);
         memcpy(out, scratch.c, 16);
 #else
-        ctx->cmac.u[0] ^= (((u64 *)out)[0] = scratch.u[0] ^ ((u64 *)inp)[0]);
-        ctx->cmac.u[1] ^= (((u64 *)out)[1] = scratch.u[1] ^ ((u64 *)inp)[1]);
+        ctx->cmac.u[0] ^= (((u64_a1 *)out)[0]
+                            = scratch.u[0] ^ ((u64_a1 *)inp)[0]);
+        ctx->cmac.u[1] ^= (((u64_a1 *)out)[1]
+                            = scratch.u[1] ^ ((u64_a1 *)inp)[1]);
 #endif
         (*block) (ctx->cmac.c, ctx->cmac.c, key);
 
diff --git a/crypto/modes/cfb128.c b/crypto/modes/cfb128.c
index e9ce4df3a5..e60b90b8c6 100644
--- a/crypto/modes/cfb128.c
+++ b/crypto/modes/cfb128.c
@@ -11,6 +11,12 @@
 #include <openssl/crypto.h>
 #include "crypto/modes.h"
 
+#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
+typedef size_t size_t_aX __attribute((__aligned__(1)));
+#else
+typedef size_t size_t_aX;
+#endif
+
 /*
  * The input and output encrypted as though 128bit cfb mode is being used.
  * The extra state information to record how much of the 128bit block we have
@@ -43,8 +49,9 @@ void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
                 while (len >= 16) {
                     (*block) (ivec, ivec, key);
                     for (; n < 16; n += sizeof(size_t)) {
-                        *(size_t *)(out + n) =
-                            *(size_t *)(ivec + n) ^= *(size_t *)(in + n);
+                        *(size_t_aX *)(out + n) =
+                            *(size_t_aX *)(ivec + n)
+                                ^= *(size_t_aX *)(in + n);
                     }
                     len -= 16;
                     out += 16;
@@ -92,9 +99,10 @@ void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out,
                 while (len >= 16) {
                     (*block) (ivec, ivec, key);
                     for (; n < 16; n += sizeof(size_t)) {
-                        size_t t = *(size_t *)(in + n);
-                        *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
-                        *(size_t *)(ivec + n) = t;
+                        size_t t = *(size_t_aX *)(in + n);
+                        *(size_t_aX *)(out + n)
+                            = *(size_t_aX *)(ivec + n) ^ t;
+                        *(size_t_aX *)(ivec + n) = t;
                     }
                     len -= 16;
                     out += 16;
diff --git a/crypto/modes/ctr128.c b/crypto/modes/ctr128.c
index ff7499b34a..fc1db42d7f 100644
--- a/crypto/modes/ctr128.c
+++ b/crypto/modes/ctr128.c
@@ -11,6 +11,12 @@
 #include <openssl/crypto.h>
 #include "crypto/modes.h"
 
+#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
+typedef size_t size_t_aX __attribute((__aligned__(1)));
+#else
+typedef size_t size_t_aX;
+#endif
+
 /*
  * NOTE: the IV/counter CTR mode is big-endian.  The code itself is
  * endian-neutral.
@@ -97,8 +103,9 @@ void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
                 (*block) (ivec, ecount_buf, key);
                 ctr128_inc_aligned(ivec);
                 for (n = 0; n < 16; n += sizeof(size_t))
-                    *(size_t *)(out + n) =
-                        *(size_t *)(in + n) ^ *(size_t *)(ecount_buf + n);
+                    *(size_t_aX *)(out + n) =
+                        *(size_t_aX *)(in + n)
+                        ^ *(size_t_aX *)(ecount_buf + n);
                 len -= 16;
                 out += 16;
                 in += 16;
diff --git a/crypto/modes/gcm128.c b/crypto/modes/gcm128.c
index d2f2da61b3..dc6d90dd0c 100644
--- a/crypto/modes/gcm128.c
+++ b/crypto/modes/gcm128.c
@@ -12,6 +12,12 @@
 #include "internal/cryptlib.h"
 #include "crypto/modes.h"
 
+#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
+typedef size_t size_t_aX __attribute((__aligned__(1)));
+#else
+typedef size_t size_t_aX;
+#endif
+
 #if defined(BSWAP4) && defined(STRICT_ALIGNMENT)
 /* redefine, because alignment is ensured */
 # undef  GETU32
@@ -1080,8 +1086,8 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
                 size_t j = GHASH_CHUNK;
 
                 while (j) {
-                    size_t *out_t = (size_t *)out;
-                    const size_t *in_t = (const size_t *)in;
+                    size_t_aX *out_t = (size_t_aX *)out;
+                    const size_t_aX *in_t = (const size_t_aX *)in;
 
                     (*block) (ctx->Yi.c, ctx->EKi.c, key);
                     ++ctr;
@@ -1107,8 +1113,8 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
                 size_t j = i;
 
                 while (len >= 16) {
-                    size_t *out_t = (size_t *)out;
-                    const size_t *in_t = (const size_t *)in;
+                    size_t_aX *out_t = (size_t_aX *)out;
+                    const size_t_aX *in_t = (const size_t_aX *)in;
 
                     (*block) (ctx->Yi.c, ctx->EKi.c, key);
                     ++ctr;
@@ -1318,8 +1324,8 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
 
                 GHASH(ctx, in, GHASH_CHUNK);
                 while (j) {
-                    size_t *out_t = (size_t *)out;
-                    const size_t *in_t = (const size_t *)in;
+                    size_t_aX *out_t = (size_t_aX *)out;
+                    const size_t_aX *in_t = (const size_t_aX *)in;
 
                     (*block) (ctx->Yi.c, ctx->EKi.c, key);
                     ++ctr;
@@ -1343,8 +1349,8 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
             if ((i = (len & (size_t)-16))) {
                 GHASH(ctx, in, i);
                 while (len >= 16) {
-                    size_t *out_t = (size_t *)out;
-                    const size_t *in_t = (const size_t *)in;
+                    size_t_aX *out_t = (size_t_aX *)out;
+                    const size_t_aX *in_t = (const size_t_aX *)in;
 
                     (*block) (ctx->Yi.c, ctx->EKi.c, key);
                     ++ctr;
diff --git a/crypto/modes/ofb128.c b/crypto/modes/ofb128.c
index 2eca09bc1b..e9b24f863e 100644
--- a/crypto/modes/ofb128.c
+++ b/crypto/modes/ofb128.c
@@ -11,6 +11,12 @@
 #include <openssl/crypto.h>
 #include "crypto/modes.h"
 
+#if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
+typedef size_t size_t_aX __attribute((__aligned__(1)));
+#else
+typedef size_t size_t_aX;
+#endif
+
 /*
  * The input and output encrypted as though 128bit ofb mode is being used.
  * The extra state information to record how much of the 128bit block we have
@@ -41,8 +47,9 @@ void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
             while (len >= 16) {
                 (*block) (ivec, ivec, key);
                 for (; n < 16; n += sizeof(size_t))
-                    *(size_t *)(out + n) =
-                        *(size_t *)(in + n) ^ *(size_t *)(ivec + n);
+                    *(size_t_aX *)(out + n) =
+                        *(size_t_aX *)(in + n)
+                        ^ *(size_t_aX *)(ivec + n);
                 len -= 16;
                 out += 16;
                 in += 16;
diff --git a/crypto/modes/xts128.c b/crypto/modes/xts128.c
index 9d9b65caa5..9dbcb5bc9a 100644
--- a/crypto/modes/xts128.c
+++ b/crypto/modes/xts128.c
@@ -11,6 +11,14 @@
 #include <openssl/crypto.h>
 #include "crypto/modes.h"
 
+#ifndef STRICT_ALIGNMENT
+# ifdef __GNUC__
+typedef u64 u64_a1 __attribute((__aligned__(1)));
+# else
+typedef u64 u64_a1;
+# endif
+#endif
+
 int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
                           const unsigned char iv[16],
                           const unsigned char *inp, unsigned char *out,
@@ -45,8 +53,8 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
         scratch.u[0] ^= tweak.u[0];
         scratch.u[1] ^= tweak.u[1];
 #else
-        scratch.u[0] = ((u64 *)inp)[0] ^ tweak.u[0];
-        scratch.u[1] = ((u64 *)inp)[1] ^ tweak.u[1];
+        scratch.u[0] = ((u64_a1 *)inp)[0] ^ tweak.u[0];
+        scratch.u[1] = ((u64_a1 *)inp)[1] ^ tweak.u[1];
 #endif
         (*ctx->block1) (scratch.c, scratch.c, ctx->key1);
 #if defined(STRICT_ALIGNMENT)
@@ -54,8 +62,8 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
         scratch.u[1] ^= tweak.u[1];
         memcpy(out, scratch.c, 16);
 #else
-        ((u64 *)out)[0] = scratch.u[0] ^= tweak.u[0];
-        ((u64 *)out)[1] = scratch.u[1] ^= tweak.u[1];
+        ((u64_a1 *)out)[0] = scratch.u[0] ^= tweak.u[0];
+        ((u64_a1 *)out)[1] = scratch.u[1] ^= tweak.u[1];
 #endif
         inp += 16;
         out += 16;
@@ -128,8 +136,8 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
         scratch.u[0] ^= tweak1.u[0];
         scratch.u[1] ^= tweak1.u[1];
 #else
-        scratch.u[0] = ((u64 *)inp)[0] ^ tweak1.u[0];
-        scratch.u[1] = ((u64 *)inp)[1] ^ tweak1.u[1];
+        scratch.u[0] = ((u64_a1 *)inp)[0] ^ tweak1.u[0];
+        scratch.u[1] = ((u64_a1 *)inp)[1] ^ tweak1.u[1];
 #endif
         (*ctx->block1) (scratch.c, scratch.c, ctx->key1);
         scratch.u[0] ^= tweak1.u[0];
@@ -148,8 +156,8 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx,
         scratch.u[1] ^= tweak.u[1];
         memcpy(out, scratch.c, 16);
 #else
-        ((u64 *)out)[0] = scratch.u[0] ^ tweak.u[0];
-        ((u64 *)out)[1] = scratch.u[1] ^ tweak.u[1];
+        ((u64_a1 *)out)[0] = scratch.u[0] ^ tweak.u[0];
+        ((u64_a1 *)out)[1] = scratch.u[1] ^ tweak.u[1];
 #endif
     }