[PATCH v5 5/8] crypto: x86/cast6: Remove glue function macro usage

Kees Cook
2019-11-13T18:26:48Z

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.

Co-developed-by: João Moreira <joao.moreira@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/crypto/cast6_avx_glue.c | 70 +++++++++++++++-----------------
crypto/cast6_generic.c | 6 ++-
include/crypto/cast6.h | 4 +-
3 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/arch/x86/crypto/cast6_avx_glue.c b/arch/x86/crypto/cast6_avx_glue.c
index a8a38fffb4a9..299cef14a762 100644
--- a/arch/x86/crypto/cast6_avx_glue.c
+++ b/arch/x86/crypto/cast6_avx_glue.c
@@ -20,20 +20,17 @@

#define CAST6_PARALLEL_BLOCKS 8

-asmlinkage void cast6_ecb_enc_8way(struct cast6_ctx *ctx, u8 *dst,
- const u8 *src);
-asmlinkage void cast6_ecb_dec_8way(struct cast6_ctx *ctx, u8 *dst,
- const u8 *src);
-
-asmlinkage void cast6_cbc_dec_8way(struct cast6_ctx *ctx, u8 *dst,
- const u8 *src);
-asmlinkage void cast6_ctr_8way(struct cast6_ctx *ctx, u8 *dst, const u8 *src,
+asmlinkage void cast6_ecb_enc_8way(void *ctx, u8 *dst, const u8 *src);
+asmlinkage void cast6_ecb_dec_8way(void *ctx, u8 *dst, const u8 *src);
+
+asmlinkage void cast6_cbc_dec_8way(void *ctx, u8 *dst, const u8 *src);
+asmlinkage void cast6_ctr_8way(void *ctx, u8 *dst, const u8 *src,
le128 *iv);

-asmlinkage void cast6_xts_enc_8way(struct cast6_ctx *ctx, u8 *dst,
- const u8 *src, le128 *iv);
-asmlinkage void cast6_xts_dec_8way(struct cast6_ctx *ctx, u8 *dst,
- const u8 *src, le128 *iv);
+asmlinkage void cast6_xts_enc_8way(void *ctx, u8 *dst, const u8 *src,
+ le128 *iv);
+asmlinkage void cast6_xts_dec_8way(void *ctx, u8 *dst, const u8 *src,
+ le128 *iv);

static int cast6_setkey_skcipher(struct crypto_skcipher *tfm,
const u8 *key, unsigned int keylen)
@@ -41,21 +38,23 @@ static int cast6_setkey_skcipher(struct crypto_skcipher *tfm,
return cast6_setkey(&tfm->base, key, keylen);
}

-static void cast6_xts_enc(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void cast6_xts_enc(void *ctx, u8 *dst, const u8 *src, le128 *iv)
{
- glue_xts_crypt_128bit_one(ctx, dst, src, iv,
- GLUE_FUNC_CAST(__cast6_encrypt));
+ glue_xts_crypt_128bit_one(ctx, (u128 *)dst, (const u128 *)src, iv,
+ __cast6_encrypt);
}

-static void cast6_xts_dec(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void cast6_xts_dec(void *ctx, u8 *dst, const u8 *src, le128 *iv)
{
- glue_xts_crypt_128bit_one(ctx, dst, src, iv,
- GLUE_FUNC_CAST(__cast6_decrypt));
+ glue_xts_crypt_128bit_one(ctx, (u128 *)dst, (const u128 *)src, iv,
+ __cast6_decrypt);
}

-static void cast6_crypt_ctr(void *ctx, u128 *dst, const u128 *src, le128 *iv)
+static void cast6_crypt_ctr(void *ctx, u8 *d, const u8 *s, le128 *iv)
{
be128 ctrblk;
+ u128 *dst = (u128 *)d;
+ const u128 *src = (const u128 *)s;

le128_to_be128(&ctrblk, iv);
le128_inc(iv);
@@ -70,10 +69,10 @@ static const struct common_glue_ctx cast6_enc = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .ecb = GLUE_FUNC_CAST(cast6_ecb_enc_8way) }
+ .fn_u = { .ecb = cast6_ecb_enc_8way }
}, {
.num_blocks = 1,
- .fn_u = { .ecb = GLUE_FUNC_CAST(__cast6_encrypt) }
+ .fn_u = { .ecb = __cast6_encrypt }
} }
};

@@ -83,10 +82,10 @@ static const struct common_glue_ctx cast6_ctr = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .ctr = GLUE_CTR_FUNC_CAST(cast6_ctr_8way) }
+ .fn_u = { .ctr = cast6_ctr_8way }
}, {
.num_blocks = 1,
- .fn_u = { .ctr = GLUE_CTR_FUNC_CAST(cast6_crypt_ctr) }
+ .fn_u = { .ctr = cast6_crypt_ctr }
} }
};

@@ -96,10 +95,10 @@ static const struct common_glue_ctx cast6_enc_xts = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .xts = GLUE_XTS_FUNC_CAST(cast6_xts_enc_8way) }
+ .fn_u = { .xts = cast6_xts_enc_8way }
}, {
.num_blocks = 1,
- .fn_u = { .xts = GLUE_XTS_FUNC_CAST(cast6_xts_enc) }
+ .fn_u = { .xts = cast6_xts_enc }
} }
};

@@ -109,10 +108,10 @@ static const struct common_glue_ctx cast6_dec = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .ecb = GLUE_FUNC_CAST(cast6_ecb_dec_8way) }
+ .fn_u = { .ecb = cast6_ecb_dec_8way }
}, {
.num_blocks = 1,
- .fn_u = { .ecb = GLUE_FUNC_CAST(__cast6_decrypt) }
+ .fn_u = { .ecb = __cast6_decrypt }
} }
};

@@ -122,10 +121,10 @@ static const struct common_glue_ctx cast6_dec_cbc = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .cbc = GLUE_CBC_FUNC_CAST(cast6_cbc_dec_8way) }
+ .fn_u = { .cbc = cast6_cbc_dec_8way }
}, {
.num_blocks = 1,
- .fn_u = { .cbc = GLUE_CBC_FUNC_CAST(__cast6_decrypt) }
+ .fn_u = { .cbc = __cast6_decrypt }
} }
};

@@ -135,10 +134,10 @@ static const struct common_glue_ctx cast6_dec_xts = {

.funcs = { {
.num_blocks = CAST6_PARALLEL_BLOCKS,
- .fn_u = { .xts = GLUE_XTS_FUNC_CAST(cast6_xts_dec_8way) }
+ .fn_u = { .xts = cast6_xts_dec_8way }
}, {
.num_blocks = 1,
- .fn_u = { .xts = GLUE_XTS_FUNC_CAST(cast6_xts_dec) }
+ .fn_u = { .xts = cast6_xts_dec }
} }
};

@@ -154,8 +153,7 @@ static int ecb_decrypt(struct skcipher_request *req)

static int cbc_encrypt(struct skcipher_request *req)
{
- return glue_cbc_encrypt_req_128bit(GLUE_FUNC_CAST(__cast6_encrypt),
- req);
+ return glue_cbc_encrypt_req_128bit(__cast6_encrypt, req);
}

static int cbc_decrypt(struct skcipher_request *req)
@@ -199,8 +197,7 @@ static int xts_encrypt(struct skcipher_request *req)
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cast6_xts_ctx *ctx = crypto_skcipher_ctx(tfm);

- return glue_xts_req_128bit(&cast6_enc_xts, req,
- XTS_TWEAK_CAST(__cast6_encrypt),
+ return glue_xts_req_128bit(&cast6_enc_xts, req, __cast6_encrypt,
&ctx->tweak_ctx, &ctx->crypt_ctx, false);
}

@@ -209,8 +206,7 @@ static int xts_decrypt(struct skcipher_request *req)
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cast6_xts_ctx *ctx = crypto_skcipher_ctx(tfm);

- return glue_xts_req_128bit(&cast6_dec_xts, req,
- XTS_TWEAK_CAST(__cast6_encrypt),
+ return glue_xts_req_128bit(&cast6_dec_xts, req, __cast6_encrypt,
&ctx->tweak_ctx, &ctx->crypt_ctx, true);
}

diff --git a/crypto/cast6_generic.c b/crypto/cast6_generic.c
index a8248f8e2777..c51121bedf68 100644
--- a/crypto/cast6_generic.c
+++ b/crypto/cast6_generic.c
@@ -173,8 +173,9 @@ static inline void QBAR(u32 *block, u8 *Kr, u32 *Km)
block[2] ^= F1(block[3], Kr[0], Km[0]);
}

-void __cast6_encrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf)
+void __cast6_encrypt(void *ctx, u8 *outbuf, const u8 *inbuf)
{
+ struct cast6_ctx *c = ctx;
const __be32 *src = (const __be32 *)inbuf;
__be32 *dst = (__be32 *)outbuf;
u32 block[4];
@@ -211,8 +212,9 @@ static void cast6_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf)
__cast6_encrypt(crypto_tfm_ctx(tfm), outbuf, inbuf);
}

-void __cast6_decrypt(struct cast6_ctx *c, u8 *outbuf, const u8 *inbuf)
+void __cast6_decrypt(void *ctx, u8 *outbuf, const u8 *inbuf)
{
+ struct cast6_ctx *c = ctx;
const __be32 *src = (const __be32 *)inbuf;
__be32 *dst = (__be32 *)outbuf;
u32 block[4];
diff --git a/include/crypto/cast6.h b/include/crypto/cast6.h
index c71f6ef47f0f..b6c3a0324959 100644
--- a/include/crypto/cast6.h
+++ b/include/crypto/cast6.h
@@ -19,7 +19,7 @@ int __cast6_setkey(struct cast6_ctx *ctx, const u8 *key,
unsigned int keylen, u32 *flags);
int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen);

-void __cast6_encrypt(struct cast6_ctx *ctx, u8 *dst, const u8 *src);
-void __cast6_decrypt(struct cast6_ctx *ctx, u8 *dst, const u8 *src);
+void __cast6_encrypt(void *ctx, u8 *dst, const u8 *src);
+void __cast6_decrypt(void *ctx, u8 *dst, const u8 *src);

#endif
--
2.17.1