crypto: comp - Use same definition of context alloc and free ops

In commit 42d9f6c ("crypto: acomp - Move scomp stream allocation
code into acomp"), the crypto_acomp_streams struct was made to rely on
having the alloc_ctx and free_ctx operations defined in the same order
as the scomp_alg struct. But in that same commit, the alloc_ctx and
free_ctx members of scomp_alg may be randomized by structure layout
randomization, since they are contained in a pure ops structure
(containing only function pointers). If the pointers within scomp_alg
are randomized, but those in crypto_acomp_streams are not, then
the order may no longer match. This fixes the problem by removing the
union from scomp_alg so that both crypto_acomp_streams and scomp_alg
will share the same definition of alloc_ctx and free_ctx, ensuring
they will always have the same layout.

Signed-off-by: Dan Moulding <dan@danm.net>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Fixes: 42d9f6c ("crypto: acomp - Move scomp stream allocation code into acomp")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: dmoulding

crypto/842.c

@@ -54,8 +54,10 @@ static int crypto842_sdecompress(struct crypto_scomp *tfm,
 }
 
 static struct scomp_alg scomp = {
-	.alloc_ctx		= crypto842_alloc_ctx,
-	.free_ctx		= crypto842_free_ctx,
+	.streams		= {
+		.alloc_ctx	= crypto842_alloc_ctx,
+		.free_ctx	= crypto842_free_ctx,
+	},
 	.compress		= crypto842_scompress,
 	.decompress		= crypto842_sdecompress,
 	.base			= {

crypto/lz4.c

@@ -68,8 +68,10 @@ static int lz4_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 }
 
 static struct scomp_alg scomp = {
-	.alloc_ctx		= lz4_alloc_ctx,
-	.free_ctx		= lz4_free_ctx,
+	.streams		= {
+		.alloc_ctx	= lz4_alloc_ctx,
+		.free_ctx	= lz4_free_ctx,
+	},
 	.compress		= lz4_scompress,
 	.decompress		= lz4_sdecompress,
 	.base			= {

crypto/lz4hc.c

@@ -66,8 +66,10 @@ static int lz4hc_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 }
 
 static struct scomp_alg scomp = {
-	.alloc_ctx		= lz4hc_alloc_ctx,
-	.free_ctx		= lz4hc_free_ctx,
+	.streams		= {
+		.alloc_ctx	= lz4hc_alloc_ctx,
+		.free_ctx	= lz4hc_free_ctx,
+	},
 	.compress		= lz4hc_scompress,
 	.decompress		= lz4hc_sdecompress,
 	.base			= {

crypto/lzo-rle.c

@@ -70,8 +70,10 @@ static int lzorle_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 }
 
 static struct scomp_alg scomp = {
-	.alloc_ctx		= lzorle_alloc_ctx,
-	.free_ctx		= lzorle_free_ctx,
+	.streams		= {
+		.alloc_ctx	= lzorle_alloc_ctx,
+		.free_ctx	= lzorle_free_ctx,
+	},
 	.compress		= lzorle_scompress,
 	.decompress		= lzorle_sdecompress,
 	.base			= {

crypto/lzo.c

@@ -70,8 +70,10 @@ static int lzo_sdecompress(struct crypto_scomp *tfm, const u8 *src,
 }
 
 static struct scomp_alg scomp = {
-	.alloc_ctx		= lzo_alloc_ctx,
-	.free_ctx		= lzo_free_ctx,
+	.streams		= {
+		.alloc_ctx	= lzo_alloc_ctx,
+		.free_ctx	= lzo_free_ctx,
+	},
 	.compress		= lzo_scompress,
 	.decompress		= lzo_sdecompress,
 	.base			= {

drivers/crypto/nx/nx-common-powernv.c

@@ -1043,8 +1043,10 @@ static struct scomp_alg nx842_powernv_alg = {
 	.base.cra_priority	= 300,
 	.base.cra_module	= THIS_MODULE,
 
-	.alloc_ctx		= nx842_powernv_crypto_alloc_ctx,
-	.free_ctx		= nx842_crypto_free_ctx,
+	.streams		= {
+		.alloc_ctx	= nx842_powernv_crypto_alloc_ctx,
+		.free_ctx	= nx842_crypto_free_ctx,
+	},
 	.compress		= nx842_crypto_compress,
 	.decompress		= nx842_crypto_decompress,
 };

drivers/crypto/nx/nx-common-pseries.c

@@ -1020,8 +1020,10 @@ static struct scomp_alg nx842_pseries_alg = {
 	.base.cra_priority	= 300,
 	.base.cra_module	= THIS_MODULE,
 
-	.alloc_ctx		= nx842_pseries_crypto_alloc_ctx,
-	.free_ctx		= nx842_crypto_free_ctx,
+	.streams		= {
+		.alloc_ctx	= nx842_pseries_crypto_alloc_ctx,
+		.free_ctx	= nx842_crypto_free_ctx,
+	},
 	.compress		= nx842_crypto_compress,
 	.decompress		= nx842_crypto_decompress,
 };

include/crypto/internal/scompress.h

@@ -18,11 +18,8 @@ struct crypto_scomp {
 /**
  * struct scomp_alg - synchronous compression algorithm
  *
- * @alloc_ctx:	Function allocates algorithm specific context
- * @free_ctx:	Function frees context allocated with alloc_ctx
  * @compress:	Function performs a compress operation
  * @decompress:	Function performs a de-compress operation
- * @base:	Common crypto API algorithm data structure
  * @streams:	Per-cpu memory for algorithm
  * @calg:	Cmonn algorithm data structure shared with acomp
  */
@@ -34,13 +31,7 @@ struct scomp_alg {
 			  unsigned int slen, u8 *dst, unsigned int *dlen,
 			  void *ctx);
 
-	union {
-		struct {
-			void *(*alloc_ctx)(void);
-			void (*free_ctx)(void *ctx);
-		};
-		struct crypto_acomp_streams streams;
-	};
+	struct crypto_acomp_streams streams;
 
 	union {
 		struct COMP_ALG_COMMON;