[PATCH v5 1/8] crypto: x86/glue_helper: Regularize function prototypes

[Kees Cook <keescook@chromium.org>]

The crypto glue performed function prototype casting to make indirect
calls to assembly routines. Instead of performing casts at the call
sites (which trips Control Flow Integrity prototype checking), switch
each prototype to a common standard set of arguments which allows the
incremental removal of the existing macros. In order to keep pointer
math unchanged, internal casting between u128 pointers and u8 pointers
is added.

Co-developed-by: João Moreira <joao.moreira@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/crypto/glue_helper.c             | 13 +++++++++----
 arch/x86/include/asm/crypto/glue_helper.h |  6 +++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/x86/crypto/glue_helper.c b/arch/x86/crypto/glue_helper.c
index d15b99397480..2eb1fc017187 100644
--- a/arch/x86/crypto/glue_helper.c
+++ b/arch/x86/crypto/glue_helper.c
@@ -134,7 +134,8 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
 				src -= num_blocks - 1;
 				dst -= num_blocks - 1;
 
-				gctx->funcs[i].fn_u.cbc(ctx, dst, src);
+				gctx->funcs[i].fn_u.cbc(ctx, (u8 *)dst,
+							(const u8 *)src);
 
 				nbytes -= func_bytes;
 				if (nbytes < bsize)
@@ -188,7 +189,9 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 
 			/* Process multi-block batch */
 			do {
-				gctx->funcs[i].fn_u.ctr(ctx, dst, src, &ctrblk);
+				gctx->funcs[i].fn_u.ctr(ctx, (u8 *)dst,
+							(const u8 *)src,
+							&ctrblk);
 				src += num_blocks;
 				dst += num_blocks;
 				nbytes -= func_bytes;
@@ -210,7 +213,8 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 
 		be128_to_le128(&ctrblk, (be128 *)walk.iv);
 		memcpy(&tmp, walk.src.virt.addr, nbytes);
-		gctx->funcs[gctx->num_funcs - 1].fn_u.ctr(ctx, &tmp, &tmp,
+		gctx->funcs[gctx->num_funcs - 1].fn_u.ctr(ctx, (u8 *)&tmp,
+							  (const u8 *)&tmp,
 							  &ctrblk);
 		memcpy(walk.dst.virt.addr, &tmp, nbytes);
 		le128_to_be128((be128 *)walk.iv, &ctrblk);
@@ -240,7 +244,8 @@ static unsigned int __glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 
 		if (nbytes >= func_bytes) {
 			do {
-				gctx->funcs[i].fn_u.xts(ctx, dst, src,
+				gctx->funcs[i].fn_u.xts(ctx, (u8 *)dst,
+							(const u8 *)src,
 							walk->iv);
 
 				src += num_blocks;
diff --git a/arch/x86/include/asm/crypto/glue_helper.h b/arch/x86/include/asm/crypto/glue_helper.h
index 8d4a8e1226ee..22d54e8b8375 100644
--- a/arch/x86/include/asm/crypto/glue_helper.h
+++ b/arch/x86/include/asm/crypto/glue_helper.h
@@ -12,10 +12,10 @@
 #include <crypto/b128ops.h>
 
 typedef void (*common_glue_func_t)(void *ctx, u8 *dst, const u8 *src);
-typedef void (*common_glue_cbc_func_t)(void *ctx, u128 *dst, const u128 *src);
-typedef void (*common_glue_ctr_func_t)(void *ctx, u128 *dst, const u128 *src,
+typedef void (*common_glue_cbc_func_t)(void *ctx, u8 *dst, const u8 *src);
+typedef void (*common_glue_ctr_func_t)(void *ctx, u8 *dst, const u8 *src,
 				       le128 *iv);
-typedef void (*common_glue_xts_func_t)(void *ctx, u128 *dst, const u128 *src,
+typedef void (*common_glue_xts_func_t)(void *ctx, u8 *dst, const u8 *src,
 				       le128 *iv);
 
 #define GLUE_FUNC_CAST(fn) ((common_glue_func_t)(fn))
-- 
2.17.1