pstore: fix crypto dependencies

The new crypto API use causes some problems with Kconfig dependencies,
including this link error:

fs/pstore/platform.o: In function `pstore_register':
platform.c:(.text+0x248): undefined reference to `crypto_has_alg'
platform.c:(.text+0x2a0): undefined reference to `crypto_alloc_base'
fs/pstore/platform.o: In function `pstore_unregister':
platform.c:(.text+0x498): undefined reference to `crypto_destroy_tfm'
crypto/lz4hc.o: In function `lz4hc_sdecompress':
lz4hc.c:(.text+0x1a): undefined reference to `LZ4_decompress_safe'
crypto/lz4hc.o: In function `lz4hc_decompress_crypto':
lz4hc.c:(.text+0x5a): undefined reference to `LZ4_decompress_safe'
crypto/lz4hc.o: In function `lz4hc_scompress':
lz4hc.c:(.text+0xaa): undefined reference to `LZ4_compress_HC'
crypto/lz4hc.o: In function `lz4hc_mod_init':
lz4hc.c:(.init.text+0xf): undefined reference to `crypto_register_alg'
lz4hc.c:(.init.text+0x1f): undefined reference to `crypto_register_scomp'
lz4hc.c:(.init.text+0x2f): undefined reference to `crypto_unregister_alg'

The problem is that with CONFIG_CRYPTO=m, we must not 'select CRYPTO_LZ4'
from a bool symbol, or call crypto API functions from a built-in
module.

This turns the sub-options into 'tristate' ones so the dependencies
are honored, and makes the pstore itself select the crypto core
if necessary.

Fixes: cb3bee03 ("pstore: Use crypto compress API")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>

fs/pstore/Kconfig

 config PSTORE
 	tristate "Persistent store support"
+	select CRYPTO if PSTORE_COMPRESS
 	default n
 	help
 	   This option enables generic access to platform level
@@ -13,7 +14,7 @@ config PSTORE
 	   say N.
 
 config PSTORE_DEFLATE_COMPRESS
-	bool "DEFLATE (ZLIB) compression"
+	tristate "DEFLATE (ZLIB) compression"
 	default y
 	depends on PSTORE
 	select CRYPTO_DEFLATE
@@ -22,21 +23,21 @@ config PSTORE_DEFLATE_COMPRESS
 	  algorithm support.
 
 config PSTORE_LZO_COMPRESS
-	bool "LZO compression"
+	tristate "LZO compression"
 	depends on PSTORE
 	select CRYPTO_LZO
 	help
 	  This option enables LZO compression algorithm support.
 
 config PSTORE_LZ4_COMPRESS
-	bool "LZ4 compression"
+	tristate "LZ4 compression"
 	depends on PSTORE
 	select CRYPTO_LZ4
 	help
 	  This option enables LZ4 compression algorithm support.
 
 config PSTORE_LZ4HC_COMPRESS
-	bool "LZ4HC compression"
+	tristate "LZ4HC compression"
 	depends on PSTORE
 	select CRYPTO_LZ4HC
 	help
@@ -70,19 +71,19 @@ choice
 	  The default compression algorithm is deflate.
 
 	config PSTORE_DEFLATE_COMPRESS_DEFAULT
-		bool "deflate" if PSTORE_DEFLATE_COMPRESS=y
+		bool "deflate" if PSTORE_DEFLATE_COMPRESS
 
 	config PSTORE_LZO_COMPRESS_DEFAULT
-		bool "lzo" if PSTORE_LZO_COMPRESS=y
+		bool "lzo" if PSTORE_LZO_COMPRESS
 
 	config PSTORE_LZ4_COMPRESS_DEFAULT
-		bool "lz4" if PSTORE_LZ4_COMPRESS=y
+		bool "lz4" if PSTORE_LZ4_COMPRESS
 
 	config PSTORE_LZ4HC_COMPRESS_DEFAULT
-		bool "lz4hc" if PSTORE_LZ4HC_COMPRESS=y
+		bool "lz4hc" if PSTORE_LZ4HC_COMPRESS
 
 	config PSTORE_842_COMPRESS_DEFAULT
-		bool "842" if PSTORE_842_COMPRESS=y
+		bool "842" if PSTORE_842_COMPRESS
 
 endchoice
 

fs/pstore/platform.c

@@ -28,10 +28,10 @@
 #include <linux/console.h>
 #include <linux/module.h>
 #include <linux/pstore.h>
-#ifdef CONFIG_PSTORE_LZO_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
 #include <linux/lzo.h>
 #endif
-#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
+#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 #include <linux/lz4.h>
 #endif
 #include <linux/crypto.h>
@@ -142,7 +142,7 @@ bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
 }
 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
 
-#ifdef CONFIG_PSTORE_DEFLATE_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
 static int zbufsize_deflate(size_t size)
 {
 	size_t cmpr;
@@ -171,21 +171,21 @@ static int zbufsize_deflate(size_t size)
 }
 #endif
 
-#ifdef CONFIG_PSTORE_LZO_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
 static int zbufsize_lzo(size_t size)
 {
 	return lzo1x_worst_compress(size);
 }
 #endif
 
-#if defined(CONFIG_PSTORE_LZ4_COMPRESS) || defined(CONFIG_PSTORE_LZ4HC_COMPRESS)
+#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 static int zbufsize_lz4(size_t size)
 {
 	return LZ4_compressBound(size);
 }
 #endif
 
-#ifdef CONFIG_PSTORE_842_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
 static int zbufsize_842(size_t size)
 {
 	return size;
@@ -195,31 +195,31 @@ static int zbufsize_842(size_t size)
 static const struct pstore_zbackend *zbackend __ro_after_init;
 
 static const struct pstore_zbackend zbackends[] = {
-#ifdef CONFIG_PSTORE_DEFLATE_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
 	{
 		.zbufsize	= zbufsize_deflate,
 		.name		= "deflate",
 	},
 #endif
-#ifdef CONFIG_PSTORE_LZO_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
 	{
 		.zbufsize	= zbufsize_lzo,
 		.name		= "lzo",
 	},
 #endif
-#ifdef CONFIG_PSTORE_LZ4_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
 	{
 		.zbufsize	= zbufsize_lz4,
 		.name		= "lz4",
 	},
 #endif
-#ifdef CONFIG_PSTORE_LZ4HC_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 	{
 		.zbufsize	= zbufsize_lz4,
 		.name		= "lz4hc",
 	},
 #endif
-#ifdef CONFIG_PSTORE_842_COMPRESS
+#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
 	{
 		.zbufsize	= zbufsize_842,
 		.name		= "842",