From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
To: Not Much Mail <notmuch@notmuchmail.org>
Date: Fri, 27 Nov 2009 21:28:03 -0600
Message-Id: <1259378883-9181-1-git-send-email-jeff@ocjtech.us>
Subject: [notmuch] [PATCH] Use libgcrypt for hashing.
Precedence: list

Instead of including a private implementation of the SHA1 hash, use
libgcrypt.  This means less code of our own to maintain and it will be
easier to switch to a different hash function like SHA256.

libgcrypt was chosen because it has a fairly simple API, it's well
tested (it's used in gnutls and gnupg2), and it's licensed under the
LGPL.

Signed-off-by: Jeffrey C. Ollie <jeff@ocjtech.us>
---
 Makefile           |    6 +-
 configure          |   15 +++-
 lib/Makefile.local |    1 -
 lib/libsha1.c      |  242 ----------------------------------------------------
 lib/libsha1.h      |   67 --------------
 lib/sha1.c         |   44 +++++-----
 6 files changed, 42 insertions(+), 333 deletions(-)
 delete mode 100644 lib/libsha1.c
 delete mode 100644 lib/libsha1.h

diff --git a/Makefile b/Makefile
index 2cd1b1b..a5ff3e7 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,8 @@ gzip = gzip
 
 # Additional flags that we will append to whatever the user set.
 # These aren't intended for the user to manipulate.
-extra_cflags := $(shell pkg-config --cflags glib-2.0 gmime-2.4 talloc)
+extra_cflags := $(shell pkg-config --cflags glib-2.0 gmime-2.4 talloc) \
+	$(shell libgcrypt-config --cflags)
 extra_cxxflags := $(shell xapian-config --cxxflags)
 
 emacs_lispdir := $(shell pkg-config emacs --variable sitepkglispdir)
@@ -28,7 +29,8 @@ override CXXFLAGS += $(WARN_FLAGS) $(extra_cflags) $(extra_cxxflags)
 
 override LDFLAGS += \
 	$(shell pkg-config --libs glib-2.0 gmime-2.4 talloc) \
-	$(shell xapian-config --libs)
+	$(shell xapian-config --libs) \
+	$(shell libgcrypt-config --libs)
 
 # Include our local Makefile.local first so that its first target is default
 include Makefile.local
diff --git a/configure b/configure
index b4770ec..22f8066 100755
--- a/configure
+++ b/configure
@@ -61,6 +61,15 @@ else
     have_valgrind=
 fi
 
+if libgcrypt-config --version > /dev/null 2>&1; then
+    echo "Checking for libgcrypt development files... Yes."
+    have_libgcrypt=1
+else
+    echo "Checking for libgcrypt development files... No."
+    have_libgcrypt=0
+    errors=$((errors + 1))
+fi
+
 if [ $errors -gt 0 ]; then
     cat <<EOF
 
@@ -81,13 +90,17 @@ EOF
 	echo "	The talloc library (including development files such as headers)"
 	echo "	http://talloc.samba.org/"
     fi
+    if [ $have_libgcrypt -eq 0 ]; then
+	echo "	The libgcrypt library (including development files such as headers)"
+	echo "	http://directory.fsf.org/project/libgcrypt/"
+    fi
     cat <<EOF
 
 On a modern, package-based operating system such as Debian, you can
 install all of the dependencies with the following simple command
 line:
 
-	sudo apt-get install libxapian-dev libgmime-2.4-dev libtalloc-dev
+	sudo apt-get install libxapian-dev libgmime-2.4-dev libtalloc-dev libgcrypt-dev
 
 On other systems, a similar command can be used, but the details of the 
 package names may be different, (such as "devel" in place of "dev").
diff --git a/lib/Makefile.local b/lib/Makefile.local
index a7562c9..28c024c 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -2,7 +2,6 @@ dir=lib
 extra_cflags += -I$(dir)
 
 libnotmuch_c_srcs =		\
-	$(dir)/libsha1.c	\
 	$(dir)/message-file.c	\
 	$(dir)/messages.c	\
 	$(dir)/sha1.c		\
diff --git a/lib/libsha1.c b/lib/libsha1.c
deleted file mode 100644
index c39a5a1..0000000
--- a/lib/libsha1.c
+++ /dev/null
@@ -1,242 +0,0 @@
-/*
- ---------------------------------------------------------------------------
- Copyright (c) 2002, Dr Brian Gladman, Worcester, UK.   All rights reserved.
-
- LICENSE TERMS
-
- The free distribution and use of this software in both source and binary
- form is allowed (with or without changes) provided that:
-
-   1. distributions of this source code include the above copyright
-      notice, this list of conditions and the following disclaimer;
-
-   2. distributions in binary form include the above copyright
-      notice, this list of conditions and the following disclaimer
-      in the documentation and/or other associated materials;
-
-   3. the copyright holder's name is not used to endorse products
-      built using this software without specific written permission.
-
- ALTERNATIVELY, provided that this notice is retained in full, this product
- may be distributed under the terms of the GNU General Public License (GPL),
- in which case the provisions of the GPL apply INSTEAD OF those given above.
-
- DISCLAIMER
-
- This software is provided 'as is' with no explicit or implied warranties
- in respect of its properties, including, but not limited to, correctness
- and/or fitness for purpose.
- ---------------------------------------------------------------------------
- Issue Date: 01/08/2005
-
- This is a byte oriented version of SHA1 that operates on arrays of bytes
- stored in memory.
-*/
-
-#include <string.h>     /* for memcpy() etc.        */
-
-#include "libsha1.h"
-
-#if defined(__cplusplus)
-extern "C"
-{
-#endif
-
-#define SHA1_BLOCK_SIZE  64
-
-#define rotl32(x,n)   (((x) << n) | ((x) >> (32 - n)))
-#define rotr32(x,n)   (((x) >> n) | ((x) << (32 - n)))
-
-#define bswap_32(x) ((rotr32((x), 24) & 0x00ff00ff) | (rotr32((x), 8) & 0xff00ff00))
-
-#if (PLATFORM_BYTE_ORDER == IS_LITTLE_ENDIAN)
-#define bsw_32(p,n) \
-    { int _i = (n); while(_i--) ((uint32_t*)p)[_i] = bswap_32(((uint32_t*)p)[_i]); }
-#else
-#define bsw_32(p,n)
-#endif
-
-#define SHA1_MASK   (SHA1_BLOCK_SIZE - 1)
-
-#if 0
-
-#define ch(x,y,z)       (((x) & (y)) ^ (~(x) & (z)))
-#define parity(x,y,z)   ((x) ^ (y) ^ (z))
-#define maj(x,y,z)      (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
-
-#else   /* Discovered by Rich Schroeppel and Colin Plumb   */
-
-#define ch(x,y,z)       ((z) ^ ((x) & ((y) ^ (z))))
-#define parity(x,y,z)   ((x) ^ (y) ^ (z))
-#define maj(x,y,z)      (((x) & (y)) | ((z) & ((x) ^ (y))))
-
-#endif
-
-/* Compile 64 bytes of hash data into SHA1 context. Note    */
-/* that this routine assumes that the byte order in the     */
-/* ctx->wbuf[] at this point is in such an order that low   */
-/* address bytes in the ORIGINAL byte stream will go in     */
-/* this buffer to the high end of 32-bit words on BOTH big  */
-/* and little endian systems                                */
-
-#ifdef ARRAY
-#define q(v,n)  v[n]
-#else
-#define q(v,n)  v##n
-#endif
-
-#define one_cycle(v,a,b,c,d,e,f,k,h)            \
-    q(v,e) += rotr32(q(v,a),27) +               \
-              f(q(v,b),q(v,c),q(v,d)) + k + h;  \
-    q(v,b)  = rotr32(q(v,b), 2)
-
-#define five_cycle(v,f,k,i)                 \
-    one_cycle(v, 0,1,2,3,4, f,k,hf(i  ));   \
-    one_cycle(v, 4,0,1,2,3, f,k,hf(i+1));   \
-    one_cycle(v, 3,4,0,1,2, f,k,hf(i+2));   \
-    one_cycle(v, 2,3,4,0,1, f,k,hf(i+3));   \
-    one_cycle(v, 1,2,3,4,0, f,k,hf(i+4))
-
-static void sha1_compile(sha1_ctx ctx[1])
-{   uint32_t    *w = ctx->wbuf;
-
-#ifdef ARRAY
-    uint32_t    v[5];
-    memcpy(v, ctx->hash, 5 * sizeof(uint32_t));
-#else
-    uint32_t    v0, v1, v2, v3, v4;
-    v0 = ctx->hash[0]; v1 = ctx->hash[1];
-    v2 = ctx->hash[2]; v3 = ctx->hash[3];
-    v4 = ctx->hash[4];
-#endif
-
-#define hf(i)   w[i]
-
-    five_cycle(v, ch, 0x5a827999,  0);
-    five_cycle(v, ch, 0x5a827999,  5);
-    five_cycle(v, ch, 0x5a827999, 10);
-    one_cycle(v,0,1,2,3,4, ch, 0x5a827999, hf(15)); \
-
-#undef  hf
-#define hf(i) (w[(i) & 15] = rotl32(                    \
-                 w[((i) + 13) & 15] ^ w[((i) + 8) & 15] \
-               ^ w[((i) +  2) & 15] ^ w[(i) & 15], 1))
-
-    one_cycle(v,4,0,1,2,3, ch, 0x5a827999, hf(16));
-    one_cycle(v,3,4,0,1,2, ch, 0x5a827999, hf(17));
-    one_cycle(v,2,3,4,0,1, ch, 0x5a827999, hf(18));
-    one_cycle(v,1,2,3,4,0, ch, 0x5a827999, hf(19));
-
-    five_cycle(v, parity, 0x6ed9eba1,  20);
-    five_cycle(v, parity, 0x6ed9eba1,  25);
-    five_cycle(v, parity, 0x6ed9eba1,  30);
-    five_cycle(v, parity, 0x6ed9eba1,  35);
-
-    five_cycle(v, maj, 0x8f1bbcdc,  40);
-    five_cycle(v, maj, 0x8f1bbcdc,  45);
-    five_cycle(v, maj, 0x8f1bbcdc,  50);
-    five_cycle(v, maj, 0x8f1bbcdc,  55);
-
-    five_cycle(v, parity, 0xca62c1d6,  60);
-    five_cycle(v, parity, 0xca62c1d6,  65);
-    five_cycle(v, parity, 0xca62c1d6,  70);
-    five_cycle(v, parity, 0xca62c1d6,  75);
-
-#ifdef ARRAY
-    ctx->hash[0] += v[0]; ctx->hash[1] += v[1];
-    ctx->hash[2] += v[2]; ctx->hash[3] += v[3];
-    ctx->hash[4] += v[4];
-#else
-    ctx->hash[0] += v0; ctx->hash[1] += v1;
-    ctx->hash[2] += v2; ctx->hash[3] += v3;
-    ctx->hash[4] += v4;
-#endif
-}
-
-void sha1_begin(sha1_ctx ctx[1])
-{
-    ctx->count[0] = ctx->count[1] = 0;
-    ctx->hash[0] = 0x67452301;
-    ctx->hash[1] = 0xefcdab89;
-    ctx->hash[2] = 0x98badcfe;
-    ctx->hash[3] = 0x10325476;
-    ctx->hash[4] = 0xc3d2e1f0;
-}
-
-/* SHA1 hash data in an array of bytes into hash buffer and */
-/* call the hash_compile function as required.              */
-
-void sha1_hash(const unsigned char data[], unsigned long len, sha1_ctx ctx[1])
-{   uint32_t pos = (uint32_t)(ctx->count[0] & SHA1_MASK),
-            space = SHA1_BLOCK_SIZE - pos;
-    const unsigned char *sp = data;
-
-    if((ctx->count[0] += len) < len)
-        ++(ctx->count[1]);
-
-    while(len >= space)     /* tranfer whole blocks if possible  */
-    {
-        memcpy(((unsigned char*)ctx->wbuf) + pos, sp, space);
-        sp += space; len -= space; space = SHA1_BLOCK_SIZE; pos = 0;
-        bsw_32(ctx->wbuf, SHA1_BLOCK_SIZE >> 2);
-        sha1_compile(ctx);
-    }
-
-    memcpy(((unsigned char*)ctx->wbuf) + pos, sp, len);
-}
-
-/* SHA1 final padding and digest calculation  */
-
-void sha1_end(unsigned char hval[], sha1_ctx ctx[1])
-{   uint32_t    i = (uint32_t)(ctx->count[0] & SHA1_MASK);
-
-    /* put bytes in the buffer in an order in which references to   */
-    /* 32-bit words will put bytes with lower addresses into the    */
-    /* top of 32 bit words on BOTH big and little endian machines   */
-    bsw_32(ctx->wbuf, (i + 3) >> 2);
-
-    /* we now need to mask valid bytes and add the padding which is */
-    /* a single 1 bit and as many zero bits as necessary. Note that */
-    /* we can always add the first padding byte here because the    */
-    /* buffer always has at least one empty slot                    */
-    ctx->wbuf[i >> 2] &= 0xffffff80 << 8 * (~i & 3);
-    ctx->wbuf[i >> 2] |= 0x00000080 << 8 * (~i & 3);
-
-    /* we need 9 or more empty positions, one for the padding byte  */
-    /* (above) and eight for the length count. If there is not      */
-    /* enough space, pad and empty the buffer                       */
-    if(i > SHA1_BLOCK_SIZE - 9)
-    {
-        if(i < 60) ctx->wbuf[15] = 0;
-        sha1_compile(ctx);
-        i = 0;
-    }
-    else    /* compute a word index for the empty buffer positions  */
-        i = (i >> 2) + 1;
-
-    while(i < 14) /* and zero pad all but last two positions        */
-        ctx->wbuf[i++] = 0;
-
-    /* the following 32-bit length fields are assembled in the      */
-    /* wrong byte order on little endian machines but this is       */
-    /* corrected later since they are only ever used as 32-bit      */
-    /* word values.                                                 */
-    ctx->wbuf[14] = (ctx->count[1] << 3) | (ctx->count[0] >> 29);
-    ctx->wbuf[15] = ctx->count[0] << 3;
-    sha1_compile(ctx);
-
-    /* extract the hash value as bytes in case the hash buffer is   */
-    /* misaligned for 32-bit words                                  */
-    for(i = 0; i < SHA1_DIGEST_SIZE; ++i)
-        hval[i] = (unsigned char)(ctx->hash[i >> 2] >> (8 * (~i & 3)));
-}
-
-void sha1(unsigned char hval[], const unsigned char data[], unsigned long len)
-{   sha1_ctx    cx[1];
-
-    sha1_begin(cx); sha1_hash(data, len, cx); sha1_end(hval, cx);
-}
-
-#if defined(__cplusplus)
-}
-#endif
diff --git a/lib/libsha1.h b/lib/libsha1.h
deleted file mode 100644
index b4dca93..0000000
--- a/lib/libsha1.h
+++ /dev/null
@@ -1,67 +0,0 @@
-/*
- ---------------------------------------------------------------------------
- Copyright (c) 2002, Dr Brian Gladman, Worcester, UK.   All rights reserved.
-
- LICENSE TERMS
-
- The free distribution and use of this software in both source and binary
- form is allowed (with or without changes) provided that:
-
-   1. distributions of this source code include the above copyright
-      notice, this list of conditions and the following disclaimer;
-
-   2. distributions in binary form include the above copyright
-      notice, this list of conditions and the following disclaimer
-      in the documentation and/or other associated materials;
-
-   3. the copyright holder's name is not used to endorse products
-      built using this software without specific written permission.
-
- ALTERNATIVELY, provided that this notice is retained in full, this product
- may be distributed under the terms of the GNU General Public License (GPL),
- in which case the provisions of the GPL apply INSTEAD OF those given above.
-
- DISCLAIMER
-
- This software is provided 'as is' with no explicit or implied warranties
- in respect of its properties, including, but not limited to, correctness
- and/or fitness for purpose.
- ---------------------------------------------------------------------------
- Issue Date: 01/08/2005
-*/
-
-#ifndef _SHA1_H
-#define _SHA1_H
-
-#if defined(__cplusplus)
-extern "C"
-{
-#endif
-#if 0
-} /* Appleasing Emacs */
-#endif
-
-#include <stdint.h>
-
-/* Size of SHA1 digest */
-
-#define SHA1_DIGEST_SIZE 20
-
-/* type to hold the SHA1 context  */
-
-typedef struct
-{   uint32_t count[2];
-    uint32_t hash[5];
-    uint32_t wbuf[16];
-} sha1_ctx;
-
-void sha1_begin(sha1_ctx ctx[1]);
-void sha1_hash(const unsigned char data[], unsigned long len, sha1_ctx ctx[1]);
-void sha1_end(unsigned char hval[], sha1_ctx ctx[1]);
-void sha1(unsigned char hval[], const unsigned char data[], unsigned long len);
-
-#if defined(__cplusplus)
-}
-#endif
-
-#endif
diff --git a/lib/sha1.c b/lib/sha1.c
index cc48108..0d22cac 100644
--- a/lib/sha1.c
+++ b/lib/sha1.c
@@ -20,21 +20,24 @@
 
 #include "notmuch-private.h"
 
-#include "libsha1.h"
+#include <gcrypt.h>
 
-/* Just some simple interfaces on top of libsha1 so that we can leave
- * libsha1 as untouched as possible. */
+/* Just some simple interfaces on top of libgcrypt */
 
 static char *
-_hex_of_sha1_digest (const unsigned char digest[SHA1_DIGEST_SIZE])
+_hex_of_sha1_digest (gcry_md_hd_t c)
 {
     char *result, *r;
+    unsigned char *digest;
     int i;
+    int digest_size;
 
-    result = xcalloc (SHA1_DIGEST_SIZE * 2 + 1, 1);
+    digest_size = gcry_md_get_algo_dlen(gcry_md_get_algo(c));
+    digest = gcry_md_read(c, 0);
+    result = xcalloc (digest_size * 2 + 1, 1);
 
     for (r = result, i = 0;
-	 i < SHA1_DIGEST_SIZE;
+	 i < digest_size;
 	 r += 2, i++)
     {
 	sprintf (r, "%02x", digest[i]);
@@ -52,16 +55,16 @@ _hex_of_sha1_digest (const unsigned char digest[SHA1_DIGEST_SIZE])
 char *
 notmuch_sha1_of_string (const char *str)
 {
-    sha1_ctx sha1;
-    unsigned char digest[SHA1_DIGEST_SIZE];
-
-    sha1_begin (&sha1);
-
-    sha1_hash ((unsigned char *) str, strlen (str) + 1, &sha1);
+    char *result;
+    gcry_md_hd_t c;
 
-    sha1_end (digest, &sha1);
+    gcry_md_open (&c, GCRY_MD_SHA1, 0);
+    gcry_md_write (c, str, strlen (str) + 1);
+    gcry_md_final (c);
+    result = _hex_of_sha1_digest (c);
+    gcry_md_close (c);
 
-    return _hex_of_sha1_digest (digest);
+    return result;
 }
 
 /* Create a hexadecimal string version of the SHA-1 digest of the
@@ -80,15 +83,14 @@ notmuch_sha1_of_file (const char *filename)
 #define BLOCK_SIZE 4096
     unsigned char block[BLOCK_SIZE];
     size_t bytes_read;
-    sha1_ctx sha1;
-    unsigned char digest[SHA1_DIGEST_SIZE];
+    gcry_md_hd_t c;
     char *result;
 
     file = fopen (filename, "r");
     if (file == NULL)
 	return NULL;
 
-    sha1_begin (&sha1);
+    gcry_md_open(&c, GCRY_MD_SHA1, 0);
 
     while (1) {
 	bytes_read = fread (block, 1, 4096, file);
@@ -100,13 +102,15 @@ notmuch_sha1_of_file (const char *filename)
 		return NULL;
 	    }
 	} else {
-	    sha1_hash (block, bytes_read, &sha1);
+	    gcry_md_write (c, block, bytes_read);
 	}
     }
 
-    sha1_end (digest, &sha1);
+    gcry_md_final (c);
+
+    result = _hex_of_sha1_digest (c);
 
-    result = _hex_of_sha1_digest (digest);
+    gcry_md_close (c);
 
     fclose (file);
 
-- 
1.6.5.2