[PATCH v5 6/8] crypto: x86/aesni: Remove glue function macro usage

[Kees Cook]

In order to remove the callsite function casts, regularize the function
prototypes for helpers to avoid triggering Control-Flow Integrity checks
during indirect function calls. Where needed, to avoid changes to
pointer math, u8 pointers are internally cast back to u128 pointers.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 arch/x86/crypto/aesni-intel_glue.c | 45 +++++++++++++-----------------
 1 file changed, 19 insertions(+), 26 deletions(-)

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 3e707e81afdb..f47afa5ae8ca 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -83,10 +83,8 @@ struct gcm_context_data {
 
 asmlinkage int aesni_set_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
 			     unsigned int key_len);
-asmlinkage void aesni_enc(struct crypto_aes_ctx *ctx, u8 *out,
-			  const u8 *in);
-asmlinkage void aesni_dec(struct crypto_aes_ctx *ctx, u8 *out,
-			  const u8 *in);
+asmlinkage void aesni_enc(void *ctx, u8 *out, const u8 *in);
+asmlinkage void aesni_dec(void *ctx, u8 *out, const u8 *in);
 asmlinkage void aesni_ecb_enc(struct crypto_aes_ctx *ctx, u8 *out,
 			      const u8 *in, unsigned int len);
 asmlinkage void aesni_ecb_dec(struct crypto_aes_ctx *ctx, u8 *out,
@@ -107,7 +105,7 @@ asmlinkage void aesni_ctr_enc(struct crypto_aes_ctx *ctx, u8 *out,
 			      const u8 *in, unsigned int len, u8 *iv);
 
 asmlinkage void aesni_xts_crypt8(struct crypto_aes_ctx *ctx, u8 *out,
-				 const u8 *in, bool enc, u8 *iv);
+				 const u8 *in, bool enc, le128 *iv);
 
 /* asmlinkage void aesni_gcm_enc()
  * void *ctx,  AES Key schedule. Starts on a 16 byte boundary.
@@ -550,29 +548,26 @@ static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key,
 }
 
 
-static void aesni_xts_tweak(void *ctx, u8 *out, const u8 *in)
+static void aesni_xts_enc(void *ctx, u8 *dst, const u8 *src, le128 *iv)
 {
-	aesni_enc(ctx, out, in);
+	glue_xts_crypt_128bit_one(ctx, (u128 *)dst, (const u128 *)src, iv,
+				  aesni_enc);
 }
 
-static void aesni_xts_enc(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void aesni_xts_dec(void *ctx, u8 *dst, const u8 *src, le128 *iv)
 {
-	glue_xts_crypt_128bit_one(ctx, dst, src, iv, GLUE_FUNC_CAST(aesni_enc));
+	glue_xts_crypt_128bit_one(ctx, (u128 *)dst, (const u128 *)src, iv,
+				  aesni_dec);
 }
 
-static void aesni_xts_dec(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void aesni_xts_enc8(void *ctx, u8 *dst, const u8 *src, le128 *iv)
 {
-	glue_xts_crypt_128bit_one(ctx, dst, src, iv, GLUE_FUNC_CAST(aesni_dec));
+	aesni_xts_crypt8(ctx, dst, src, true, iv);
 }
 
-static void aesni_xts_enc8(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void aesni_xts_dec8(void *ctx, u8 *dst, const u8 *src, le128 *iv)
 {
-	aesni_xts_crypt8(ctx, (u8 *)dst, (const u8 *)src, true, (u8 *)iv);
-}
-
-static void aesni_xts_dec8(void *ctx, u128 *dst, const u128 *src, le128 *iv)
-{
-	aesni_xts_crypt8(ctx, (u8 *)dst, (const u8 *)src, false, (u8 *)iv);
+	aesni_xts_crypt8(ctx, dst, src, false, iv);
 }
 
 static const struct common_glue_ctx aesni_enc_xts = {
@@ -581,10 +576,10 @@ static const struct common_glue_ctx aesni_enc_xts = {
 
 	.funcs = { {
 		.num_blocks = 8,
-		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(aesni_xts_enc8) }
+		.fn_u = { .xts = aesni_xts_enc8 }
 	}, {
 		.num_blocks = 1,
-		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(aesni_xts_enc) }
+		.fn_u = { .xts = aesni_xts_enc }
 	} }
 };
 
@@ -594,10 +589,10 @@ static const struct common_glue_ctx aesni_dec_xts = {
 
 	.funcs = { {
 		.num_blocks = 8,
-		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(aesni_xts_dec8) }
+		.fn_u = { .xts = aesni_xts_dec8 }
 	}, {
 		.num_blocks = 1,
-		.fn_u = { .xts = GLUE_XTS_FUNC_CAST(aesni_xts_dec) }
+		.fn_u = { .xts = aesni_xts_dec }
 	} }
 };
 
@@ -606,8 +601,7 @@ static int xts_encrypt(struct skcipher_request *req)
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	return glue_xts_req_128bit(&aesni_enc_xts, req,
-				   XTS_TWEAK_CAST(aesni_xts_tweak),
+	return glue_xts_req_128bit(&aesni_enc_xts, req, aesni_enc,
 				   aes_ctx(ctx->raw_tweak_ctx),
 				   aes_ctx(ctx->raw_crypt_ctx),
 				   false);
@@ -618,8 +612,7 @@ static int xts_decrypt(struct skcipher_request *req)
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	return glue_xts_req_128bit(&aesni_dec_xts, req,
-				   XTS_TWEAK_CAST(aesni_xts_tweak),
+	return glue_xts_req_128bit(&aesni_dec_xts, req, aesni_enc,
 				   aes_ctx(ctx->raw_tweak_ctx),
 				   aes_ctx(ctx->raw_crypt_ctx),
 				   true);
-- 
2.17.1