btrfs-progs: add more hash implementation providers

For environments that require certified implementations of cryptographic
primitives allow to select a library providing them. The requirements
are SHA256 and BLAKE2 (with the 2b variant and 256 bit digest).

For now there are two: libgrcrypt and libsodium (openssl does not
provide the BLAKE2b-256). Accellerated versions are typically provided
and automatically selected.

Signed-off-by: David Sterba <dsterba@suse.com>

INSTALL

@@ -14,6 +14,13 @@ For the btrfs-convert utility:
 - e2fsprogs - ext2/ext3/ext4 file system libraries, or called e2fslibs
 - libreiserfscore - reiserfs file system library version >= 3.6.27
 
+Optionally, the checksums based on cryptographic hashes can be implemeted by
+external libraries. Builtin implementations are provided in case the library
+dependencies are not desired.
+
+- libgcrypt
+- libsodium
+
 Generating documentation:
 
 - asciidoc - text document format tool

Makefile

@@ -95,6 +95,7 @@ CFLAGS = $(SUBST_CFLAGS) \
 	 -fPIC \
 	 -I$(TOPDIR) \
 	 -I$(TOPDIR)/libbtrfsutil \
+	 $(CRYPTO_CFLAGS) \
 	 $(DISABLE_WARNING_FLAGS) \
 	 $(ENABLE_WARNING_FLAGS) \
 	 $(EXTRAWARN_CFLAGS) \
@@ -121,8 +122,11 @@ LIBBTRFSUTIL_LDFLAGS = $(SUBST_LDFLAGS) \
 		       $(DEBUG_LDFLAGS_INTERNAL) \
 		       $(EXTRA_LDFLAGS)
 
-LIBS = $(LIBS_BASE)
-LIBBTRFS_LIBS = $(LIBS_BASE)
+# Default implementation
+CRYPTO_OBJECTS =
+
+LIBS = $(LIBS_BASE) $(LIBS_CRYPTO)
+LIBBTRFS_LIBS = $(LIBS_BASE) $(LIBS_CRYPTO)
 
 # Static compilation flags
 STATIC_CFLAGS = $(CFLAGS) -ffunction-sections -fdata-sections
@@ -165,7 +169,7 @@ libbtrfs_objects = send-stream.o send-utils.o kernel-lib/rbtree.o btrfs-list.o \
 		   kernel-lib/raid56.o kernel-lib/tables.o \
 		   common/device-scan.o common/path-utils.o \
 		   common/utils.o libbtrfsutil/subvolume.o libbtrfsutil/stubs.o \
-		   crypto/hash.o crypto/xxhash.o crypto/sha224-256.o crypto/blake2b-ref.o
+		   crypto/hash.o crypto/xxhash.o $(CRYPTO_OBJECTS)
 libbtrfs_headers = send-stream.h send-utils.h send.h kernel-lib/rbtree.h btrfs-list.h \
 	       crypto/crc32c.h kernel-lib/list.h kerncompat.h \
 	       kernel-lib/radix-tree.h kernel-lib/sizes.h kernel-lib/raid56.h \
@@ -290,6 +294,11 @@ btrfs_convert_cflags += -DBTRFSCONVERT_REISERFS=$(BTRFSCONVERT_REISERFS)
 btrfs_fragments_libs = -lgd -lpng -ljpeg -lfreetype
 cmds_restore_cflags = -DBTRFSRESTORE_ZSTD=$(BTRFSRESTORE_ZSTD)
 
+ifeq ($(CRYPTOPROVIDER_BUILTIN),1)
+CRYPTO_OBJECTS = crypto/sha224-256.o crypto/blake2b-ref.o
+CRYPTO_CFLAGS = -DCRYPTOPROVIDER_BUILTIN=1
+endif
+
 CHECKER_FLAGS += $(btrfs_convert_cflags)
 
 # collect values of the variables above

Makefile.inc.in

@@ -21,13 +21,16 @@ BTRFSRESTORE_ZSTD = @BTRFSRESTORE_ZSTD@
 PYTHON_BINDINGS = @PYTHON_BINDINGS@
 PYTHON = @PYTHON@
 PYTHON_CFLAGS = @PYTHON_CFLAGS@
+CRYPTOPROVIDER_BUILTIN = @CRYPTOPROVIDER_BUILTIN@
+CRYPTO_CFLAGS = @GCRYPT_CFLAGS@ @SODIUM_CFLAGS@
 
 SUBST_CFLAGS = @CFLAGS@
 SUBST_LDFLAGS = @LDFLAGS@
 
 LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ -L. -pthread
 LIBS_COMP = @ZLIB_LIBS@ @LZO2_LIBS@ @ZSTD_LIBS@
 LIBS_PYTHON = @PYTHON_LIBS@
+LIBS_CRYPTO = @GCRYPT_LIBS@ @SODIUM_LIBS@
 STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ -L. -pthread
 STATIC_LIBS_COMP = @ZLIB_LIBS_STATIC@ @LZO2_LIBS_STATIC@ @ZSTD_LIBS_STATIC@
 

README.md

@@ -98,7 +98,8 @@ Build dependencies are listed in [INSTALL](INSTALL). Implementation of checksum/
 functions is provided by copies of the respective sources to avoid adding
 dependencies that would make deployments in rescure or limited environments
 harder. The implementations are portable and not optimized for speed nor
-accelerated.
+accelerated. Optionally it's possible to use libgcrypt or libsodium
+implementations.
 
 * CRC32C: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
 * XXHASH: https://github.com/Cyan4973/xxHash

configure.ac

@@ -195,6 +195,34 @@ if test "$DISABLE_BTRFSCONVERT" = 0 && test "x$convertfs" = "x"; then
 	AC_MSG_ERROR([no filesystems for convert, use --disable-convert instead])
 fi
 
+AC_ARG_WITH([crypto],
+	    AS_HELP_STRING([[[]--with-crypto[[=builtin]]]], [provider of cryptographic primtives: builtin, libgcrypt, libsodium]),
+  [], [with_crypto=builtin]
+)
+
+cryptoprovider=
+cryptoproviderversion=
+CRYPTOPROVIDER_BUILTIN=0
+if test "$with_crypto" = "builtin"; then
+	cryptoprovider="builtin"
+	CRYPTOPROVIDER_BUILTIN=1
+	AC_DEFINE([CRYPTOPROVIDER_BUILTIN],[1],[Use builtin implementation])
+elif test "$with_crypto" = "libgcrypt"; then
+	cryptoprovider="libgcrypt"
+	PKG_CHECK_MODULES(GCRYPT, [libgcrypt >= 1.8.0])
+	AC_DEFINE([CRYPTOPROVIDER_LIBGCRYPT],[1],[Use libcrypt])
+	cryptoproviderversion=`pkg-config libgcrypt --version`
+elif test "$with_crypto" = "libsodium"; then
+	cryptoprovider="libsodium"
+	PKG_CHECK_MODULES(SODIUM, [libsodium >= 1.0.4])
+	AC_DEFINE([CRYPTOPROVIDER_LIBSODIUM],[1],[Use libsodium])
+	cryptoproviderversion=`pkg-config libsodium --version`
+else
+	AC_MSG_ERROR([unrecognized crypto provider: $with_crypto])
+fi
+AC_SUBST([CRYPTOPROVIDER_BUILTIN])
+AC_DEFINE_UNQUOTED([CRYPTOPROVIDER],["$cryptoprovider"],[Crypto implementation source name])
+
 HAVE_OWN_FIEMAP_EXTENT_SHARED_DEFINE=0
 AX_CHECK_DEFINE([linux/fiemap.h], [FIEMAP_EXTENT_SHARED], [],
 		[HAVE_OWN_FIEMAP_EXTENT_SHARED_DEFINE=1
@@ -307,6 +335,7 @@ AC_MSG_RESULT([
 	btrfs-restore zstd: ${enable_zstd}
 	Python bindings:    ${enable_python}
 	Python interpreter: ${PYTHON}
+	crypto provider:    ${cryptoprovider} ${cryptoproviderversion}
 
 	Type 'make' to compile.
 ])

crypto/hash-speedtest.c

@@ -75,8 +75,9 @@ int main(int argc, char **argv) {
 	crc32c_optimization_init();
 	memset(buf, 0, 4096);
 
-	printf("Block size: %d\n", blocksize);
-	printf("Iterations: %d\n", iterations);
+	printf("Block size:    %d\n", blocksize);
+	printf("Iterations:    %d\n", iterations);
+	printf("Implementaion: %s\n", CRYPTOPROVIDER);
 	printf("\n");
 
 	for (idx = 0; idx < ARRAY_SIZE(contestants); idx++) {

crypto/hash.c

@@ -4,6 +4,9 @@
 #include "crypto/sha.h"
 #include "crypto/blake2.h"
 
+/*
+ * Default builtin implementations
+ */
 int hash_crc32c(const u8* buf, size_t length, u8 *out)
 {
 	u32 crc = ~0;
@@ -24,6 +27,11 @@ int hash_xxhash(const u8 *buf, size_t length, u8 *out)
 	return 0;
 }
 
+/*
+ * Implementations of cryptographic primitives
+ */
+#if CRYPTOPROVIDER_BUILTIN == 1
+
 int hash_sha256(const u8 *buf, size_t len, u8 *out)
 {
 	SHA256Context context;
@@ -45,3 +53,41 @@ int hash_blake2b(const u8 *buf, size_t len, u8 *out)
 
 	return 0;
 }
+
+#endif
+
+#if CRYPTOPROVIDER_LIBGCRYPT == 1
+
+#include <gcrypt.h>
+
+int hash_sha256(const u8 *buf, size_t len, u8 *out)
+{
+	gcry_md_hash_buffer(GCRY_MD_SHA256, out, buf, len);
+	return 0;
+}
+
+int hash_blake2b(const u8 *buf, size_t len, u8 *out)
+{
+	gcry_md_hash_buffer(GCRY_MD_BLAKE2B_256, out, buf, len);
+	return 0;
+}
+
+#endif
+
+#if CRYPTOPROVIDER_LIBSODIUM == 1
+
+#include <sodium/crypto_hash_sha256.h>
+#include <sodium/crypto_generichash_blake2b.h>
+
+int hash_sha256(const u8 *buf, size_t len, u8 *out)
+{
+	return crypto_hash_sha256(out, buf, len);
+}
+
+int hash_blake2b(const u8 *buf, size_t len, u8 *out)
+{
+	return crypto_generichash_blake2b(out, CRYPTO_HASH_SIZE_MAX, buf, len,
+			NULL, 0);
+}
+
+#endif