Linux supports accessing kernel crypto API via AF_ALG since
version 2.6.38. Coreutils uses libcrypto when available and fallbacks to
generic C implementation of various hashing functions.
Add a generic afalg_stream() function which uses AF_ALG to calculate the
hash of a stream and use sendfile() when possible (regular file with size
less or equal than 0x7ffff000 (2,147,479,552) bytes, AKA MAX_RW_COUNT).
Use afalg_stream() only in sha1sum for now, but other hashes are possible.
The speed gain really depends on the CPU type, on systems which doesn't use
libcrypto ranges from ~10% to 320%.
This is a test on a Intel(R) Xeon(R) CPU E3-1265L V2 and Debian stretch:
$ truncate -s 2GB 2g.bin
$ time sha1sum 2g.bin
752ef2367f479e79e4f0cded9c270c2890506ab0 2g.bin
real 0m4.829s
user 0m4.437s
sys 0m0.391s
$ time ./sha1sum-afalg 2g.bin
752ef2367f479e79e4f0cded9c270c2890506ab0 2g.bin
real 0m3.164s
user 0m0.000s
sys 0m3.162s
Signed-off-by: Matteo Croce <mcr...@redhat.com>
---
lib/af_alg.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++
lib/af_alg.h | 51 +++++++++++++++++++++
lib/sha1.c | 19 +++++++-
modules/crypto/sha1 | 4 +-
4 files changed, 196 insertions(+), 2 deletions(-)
create mode 100644 lib/af_alg.c
create mode 100644 lib/af_alg.h
diff --git a/lib/af_alg.c b/lib/af_alg.c
new file mode 100644
index 000000000..cb6086b4d
--- /dev/null
+++ b/lib/af_alg.c
@@ -0,0 +1,124 @@
+/* af_alg.c - Functions to compute message digest from file streams using
+ Linux kernel crypto API.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ This program is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 2, or (at your option) any
+ later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Matteo Croce <mcr...@redhat.com>, 2018. */
+
+#include <config.h>
+
+#include <sys/socket.h>
+
+#ifdef AF_ALG
+
+#include <unistd.h>
+#include <string.h>
+#include <linux/if_alg.h>
+#include <sys/stat.h>
+#include <sys/sendfile.h>
+
+#include "af_alg.h"
+
+/* from linux/include/linux/fs.h: (INT_MAX & PAGE_MASK) */
+#define MAX_RW_COUNT 0x7FFFF000
+#define BLOCKSIZE 32768
+
+int
+afalg_stream (FILE * stream, void *resblock, const char *alg, ssize_t hashlen)
+{
+ struct sockaddr_alg salg = {
+ .salg_family = AF_ALG,
+ .salg_type = "hash",
+ };
+ int ret, cfd, ofd;
+ char buf[BLOCKSIZE];
+ ssize_t size;
+ struct stat st;
+
+ if (strlen (alg) >= sizeof(salg.salg_name))
+ return -EINVAL;
+
+ cfd = socket (AF_ALG, SOCK_SEQPACKET, 0);
+ if (cfd < 0)
+ return -EAFNOSUPPORT;
+
+ strcpy ((char *) salg.salg_name, alg);
+
+ ret = bind (cfd, (struct sockaddr *) &salg, sizeof (salg));
+ if (ret < 0)
+ {
+ ret = -EAFNOSUPPORT;
+ goto out_cfd;
+ }
+
+ ofd = accept (cfd, NULL, 0);
+ if (ofd < 0)
+ {
+ ret = -EAFNOSUPPORT;
+ goto out_cfd;
+ }
+
+ /* if file is a regular file, attempt sendfile() to pipe the data */
+ if (!fstat (fileno (stream), &st) && S_ISREG (st.st_mode) &&
+ st.st_size <= MAX_RW_COUNT)
+ {
+ if (sendfile (ofd, fileno (stream), NULL, st.st_size) != st.st_size)
+ {
+ ret = -EIO;
+ goto out_ofd;
+ }
+ else
+ {
+ ret = 0;
+ }
+ }
+ else
+ {
+ /* sendfile() not possible, do a classic read-write loop */
+ while ((size = fread (buf, 1, sizeof (buf), stream)))
+ {
+ if (send (ofd, buf, size, size == sizeof (buf) ? MSG_MORE : 0) == -1)
+ {
+ ret = -EIO;
+ goto out_ofd;
+ }
+ }
+ if (ferror (stream))
+ {
+ ret = -EIO;
+ goto out_ofd;
+ }
+ }
+
+ size = read (ofd, resblock, hashlen);
+ if (size != hashlen)
+ {
+ fprintf (stderr, "Error from read (%zd vs %zd bytes): %s\n",
+ size, hashlen, strerror (errno));
+ ret = -EIO;
+ }
+ else
+ {
+ ret = 0;
+ }
+out_ofd:
+ close (ofd);
+out_cfd:
+ close (cfd);
+ return ret;
+}
+
+#endif
diff --git a/lib/af_alg.h b/lib/af_alg.h
new file mode 100644
index 000000000..36a95f4bc
--- /dev/null
+++ b/lib/af_alg.h
@@ -0,0 +1,51 @@
+/* af_alg.h - Declaration of functions to compute message digest from
+ file streams using Linux kernel crypto API.
+ Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ This program is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 2, or (at your option) any
+ later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Matteo Croce <mcr...@redhat.com>, 2018. */
+
+#ifndef AF_ALG_H
+# define AF_ALG_H 1
+
+# include <stdio.h>
+# include <errno.h>
+# include <sys/socket.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+#ifdef AF_ALG
+
+int
+afalg_stream (FILE * stream, void *resblock, const char *alg, ssize_t hashlen);
+
+#else
+
+static int
+afalg_stream (FILE * stream, void *resblock, const char *alg, ssize_t hashlen)
+{
+ return -EAFNOSUPPORT;
+}
+
+#endif
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
diff --git a/lib/sha1.c b/lib/sha1.c
index 37d46b68e..21b4b323a 100644
--- a/lib/sha1.c
+++ b/lib/sha1.c
@@ -33,6 +33,12 @@
#include <stdlib.h>
#include <string.h>
+#include <sys/socket.h>
+
+#ifdef AF_ALG
+# include "af_alg.h"
+#endif
+
#if USE_UNLOCKED_IO
# include "unlocked-io.h"
#endif
@@ -130,8 +136,19 @@ sha1_stream (FILE *stream, void *resblock)
{
struct sha1_ctx ctx;
size_t sum;
+ char *buffer;
+#ifdef AF_ALG
+ int ret;
+
+ ret = afalg_stream(stream, resblock, "sha1", SHA1_DIGEST_SIZE);
+ if (!ret)
+ return 0;
+
+ if (ret == -EIO)
+ return 1;
+#endif
- char *buffer = malloc (BLOCKSIZE + 72);
+ buffer = malloc (BLOCKSIZE + 72);
if (!buffer)
return 1;
diff --git a/modules/crypto/sha1 b/modules/crypto/sha1
index d65f99418..30b7153e2 100644
--- a/modules/crypto/sha1
+++ b/modules/crypto/sha1
@@ -5,6 +5,8 @@ Files:
lib/gl_openssl.h
lib/sha1.h
lib/sha1.c
+lib/af_alg.h
+lib/af_alg.c
m4/gl-openssl.m4
m4/sha1.m4
@@ -17,7 +19,7 @@ configure.ac:
gl_SHA1
Makefile.am:
-lib_SOURCES += sha1.c
+lib_SOURCES += sha1.c af_alg.c
Include:
"sha1.h"
--
2.14.3
