Calculate the MD5 checksum of a buffer. More...

#include "config.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include "md5.h"

Include dependency graph for md5.c:

Go to the source code of this file.

Macros
#define	SWAP(n) (n)

#define	FF(b, c, d) (d ^ (b & (c ^ d)))

#define	FG(b, c, d) FF(d, b, c)

#define	FH(b, c, d) (b ^ c ^ d)

#define	FI(b, c, d) (c ^ (b \| ~d))

#define	OP(a, b, c, d, s, T)

#define	CYCLIC(w, s) (w = (w << s) \| (w >> (32 - s)))

#define	OP(f, a, b, c, d, k, s, T)

#define	alignof(type)

#define	UNALIGNED_P(p) (((size_t) p) % alignof(md5_uint32) != 0)

Functions
static void	mutt_md5_process_block (const void buffer, size_t len, struct Md5Ctx md5ctx)
	Process a block with MD5.

static void	set_uint32 (char *cp, md5_uint32 v)
	Write a 32 bit number.

static void *	mutt_md5_read_ctx (const struct Md5Ctx md5ctx, void resbuf)
	Read from the context into a buffer.

void	mutt_md5_init_ctx (struct Md5Ctx *md5ctx)
	Initialise the MD5 computation.

void *	mutt_md5_finish_ctx (struct Md5Ctx md5ctx, void resbuf)
	Process the remaining bytes in the buffer.

void *	mutt_md5 (const char str, void buf)
	Calculate the MD5 hash of a NULL-terminated string.

void *	mutt_md5_bytes (const void buffer, size_t len, void resbuf)
	Calculate the MD5 hash of a buffer.

void	mutt_md5_process (const char str, struct Md5Ctx md5ctx)
	Process a NULL-terminated string.

void	mutt_md5_process_bytes (const void buf, size_t buflen, struct Md5Ctx md5ctx)
	Process a block of data.

void	mutt_md5_toascii (const void digest, char resbuf)
	Convert a binary MD5 digest into ASCII Hexadecimal.

Variables
static const unsigned char	fillbuf [64] = { 0x80, 0 }
	This array contains the bytes used to pad the buffer to the next 64-byte boundary.

Detailed Description

Calculate the MD5 checksum of a buffer.

Authors

Ulrich Drepper
Free Software Foundation, Inc.

Copyright: 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 of the License, 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 http://www.gnu.org/licenses/.

Definition in file md5.c.

Macro Definition Documentation

◆ SWAP

#define SWAP ( n ) (n)

Definition at line 41 of file md5.c.

◆ FF

#define FF	(	b,
		c,
		d
	)	(d ^ (b & (c ^ d)))

Definition at line 51 of file md5.c.

◆ FG

#define FG	(	b,
		c,
		d
	)	FF(d, b, c)

Definition at line 52 of file md5.c.

◆ FH

#define FH	(	b,
		c,
		d
	)	(b ^ c ^ d)

Definition at line 53 of file md5.c.

◆ FI

#define FI	(	b,
		c,
		d
	)	(c ^ (b \| ~d))

Definition at line 54 of file md5.c.

◆ OP [1/2]

#define OP	(	a,
		b,
		c,
		d,
		s,
		T
	)

Value:

  do                                                                           \
  {                                                                            \
    a += FF(b, c, d) + (*cwp++ = SWAP(*words)) + T;                            \
    words++;                                                                   \
    CYCLIC(a, s);                                                              \
    a += b;                                                                    \
  } while (false)

◆ CYCLIC

#define CYCLIC	(	w,
		s
	)	(w = (w << s) \| (w >> (32 - s)))

◆ OP [2/2]

#define OP	(	f,
		a,
		b,
		c,
		d,
		k,
		s,
		T
	)

Value:

  do                                                                           \
  {                                                                            \
    a += f(b, c, d) + correct_words[k] + T;                                    \
    CYCLIC(a, s);                                                              \
    a += b;                                                                    \
  } while (false)

◆ alignof

#define alignof ( type )

Value:

  offsetof(                                                                    \
      struct {                                                                 \
        char c;                                                                \
        type x;                                                                \
      },                                                                       \
      x)

◆ UNALIGNED_P

#define UNALIGNED_P ( p ) (((size_t) p) % alignof(md5_uint32) != 0)

Function Documentation

◆ mutt_md5_process_block()

static void mutt_md5_process_block	(	const void *	buffer,
		size_t	len,
		struct Md5Ctx *	md5ctx
	)

static

Process a block with MD5.

Parameters

buffer	Buffer to hash
len	Length of buffer
md5ctx	MD5 context

Process LEN bytes of Buffer, accumulating context into MD5CTX. LEN must be a multiple of 64.

Definition at line 65 of file md5.c.

{
  md5_uint32 correct_words[16];
  const md5_uint32 *words = buffer;
  size_t nwords = len / sizeof(md5_uint32);
  const md5_uint32 *endp = words + nwords;
  md5_uint32 A = md5ctx->A;
  md5_uint32 B = md5ctx->B;
  md5_uint32 C = md5ctx->C;
  md5_uint32 D = md5ctx->D;
 
  /* First increment the byte count.  RFC1321 specifies the possible length of
   * the file up to 2^64 bits.  Here we only compute the number of bytes.  Do a
   * double word increment. */
  md5ctx->total[0] += len;
  if (md5ctx->total[0] < len)
    md5ctx->total[1]++; // LCOV_EXCL_LINE
 
  /* Process all bytes in the buffer with 64 bytes in each round of the loop. */
  while (words < endp)
  {
    md5_uint32 *cwp = correct_words;
    md5_uint32 save_A = A;
    md5_uint32 save_B = B;
    md5_uint32 save_C = C;
    md5_uint32 save_D = D;
 
    /* First round: using the given function, the context and a constant the
     * next context is computed.  Because the algorithms processing unit is a
     * 32-bit word and it is determined to work on words in little endian byte
     * order we perhaps have to change the byte order before the computation.
     * To reduce the work for the next steps we store the swapped words in the
     * array CORRECT_WORDS. */
 
#define OP(a, b, c, d, s, T)                                                   \
  do                                                                           \
  {                                                                            \
    a += FF(b, c, d) + (*cwp++ = SWAP(*words)) + T;                            \
    words++;                                                                   \
    CYCLIC(a, s);                                                              \
    a += b;                                                                    \
  } while (false)
 
/* It is unfortunate that C does not provide an operator for
 * cyclic rotation.  Hope the C compiler is smart enough. */
#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))
 
    /* Before we start, one word to the strange constants.
     * They are defined in RFC1321 as
     * T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
     * Here is an equivalent invocation using Perl:
     * perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
     */
 
    /* Round 1. */
    OP(A, B, C, D, 7, 0xd76aa478);
    OP(D, A, B, C, 12, 0xe8c7b756);
    OP(C, D, A, B, 17, 0x242070db);
    OP(B, C, D, A, 22, 0xc1bdceee);
    OP(A, B, C, D, 7, 0xf57c0faf);
    OP(D, A, B, C, 12, 0x4787c62a);
    OP(C, D, A, B, 17, 0xa8304613);
    OP(B, C, D, A, 22, 0xfd469501);
    OP(A, B, C, D, 7, 0x698098d8);
    OP(D, A, B, C, 12, 0x8b44f7af);
    OP(C, D, A, B, 17, 0xffff5bb1);
    OP(B, C, D, A, 22, 0x895cd7be);
    OP(A, B, C, D, 7, 0x6b901122);
    OP(D, A, B, C, 12, 0xfd987193);
    OP(C, D, A, B, 17, 0xa679438e);
    OP(B, C, D, A, 22, 0x49b40821);
 
/* For the second to fourth round we have the possibly swapped words
 * in CORRECT_WORDS.  Redefine the macro to take an additional first
 * argument specifying the function to use. */
#undef OP
#define OP(f, a, b, c, d, k, s, T)                                             \
  do                                                                           \
  {                                                                            \
    a += f(b, c, d) + correct_words[k] + T;                                    \
    CYCLIC(a, s);                                                              \
    a += b;                                                                    \
  } while (false)
 
    /* Round 2. */
    OP(FG, A, B, C, D, 1, 5, 0xf61e2562);
    OP(FG, D, A, B, C, 6, 9, 0xc040b340);
    OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
    OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
    OP(FG, A, B, C, D, 5, 5, 0xd62f105d);
    OP(FG, D, A, B, C, 10, 9, 0x02441453);
    OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
    OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
    OP(FG, A, B, C, D, 9, 5, 0x21e1cde6);
    OP(FG, D, A, B, C, 14, 9, 0xc33707d6);
    OP(FG, C, D, A, B, 3, 14, 0xf4d50d87);
    OP(FG, B, C, D, A, 8, 20, 0x455a14ed);
    OP(FG, A, B, C, D, 13, 5, 0xa9e3e905);
    OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8);
    OP(FG, C, D, A, B, 7, 14, 0x676f02d9);
    OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
 
    /* Round 3. */
    OP(FH, A, B, C, D, 5, 4, 0xfffa3942);
    OP(FH, D, A, B, C, 8, 11, 0x8771f681);
    OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
    OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
    OP(FH, A, B, C, D, 1, 4, 0xa4beea44);
    OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9);
    OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60);
    OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
    OP(FH, A, B, C, D, 13, 4, 0x289b7ec6);
    OP(FH, D, A, B, C, 0, 11, 0xeaa127fa);
    OP(FH, C, D, A, B, 3, 16, 0xd4ef3085);
    OP(FH, B, C, D, A, 6, 23, 0x04881d05);
    OP(FH, A, B, C, D, 9, 4, 0xd9d4d039);
    OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
    OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
    OP(FH, B, C, D, A, 2, 23, 0xc4ac5665);
 
    /* Round 4. */
    OP(FI, A, B, C, D, 0, 6, 0xf4292244);
    OP(FI, D, A, B, C, 7, 10, 0x432aff97);
    OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
    OP(FI, B, C, D, A, 5, 21, 0xfc93a039);
    OP(FI, A, B, C, D, 12, 6, 0x655b59c3);
    OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92);
    OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
    OP(FI, B, C, D, A, 1, 21, 0x85845dd1);
    OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f);
    OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
    OP(FI, C, D, A, B, 6, 15, 0xa3014314);
    OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
    OP(FI, A, B, C, D, 4, 6, 0xf7537e82);
    OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
    OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
    OP(FI, B, C, D, A, 9, 21, 0xeb86d391);
 
    /* Add the starting values of the context. */
    A += save_A;
    B += save_B;
    C += save_C;
    D += save_D;
  }
 
  /* Put checksum in context given as argument. */
  md5ctx->A = A;
  md5ctx->B = B;
  md5ctx->C = C;
  md5ctx->D = D;
}

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◆ set_uint32()

static void set_uint32	(	char *	cp,
		md5_uint32	v
	)

inlinestatic

Write a 32 bit number.

Parameters

cp	Destination for data
v	Value to write

Copy the 4 byte value from v into the memory location pointed to by *cp, If your architecture allows unaligned access this is equivalent to *(md5_uint32*) cp = v

Definition at line 226 of file md5.c.

{
  memcpy(cp, &v, sizeof(v));
}

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◆ mutt_md5_read_ctx()

static void * mutt_md5_read_ctx	(	const struct Md5Ctx *	md5ctx,
		void *	resbuf
	)

static

Read from the context into a buffer.

Parameters

md5ctx	MD5 context
resbuf	Buffer for result

Return values

ptr	Results buffer

Put result from MD5CTX in first 16 bytes following RESBUF. The result must be in little endian byte order.

Definition at line 240 of file md5.c.

{
  if (!md5ctx || !resbuf)
    return NULL;
 
  char *r = resbuf;
 
  set_uint32(r + 0 * sizeof(md5ctx->A), SWAP(md5ctx->A));
  set_uint32(r + 1 * sizeof(md5ctx->B), SWAP(md5ctx->B));
  set_uint32(r + 2 * sizeof(md5ctx->C), SWAP(md5ctx->C));
  set_uint32(r + 3 * sizeof(md5ctx->D), SWAP(md5ctx->D));
 
  return resbuf;
}

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◆ mutt_md5_init_ctx()

void mutt_md5_init_ctx ( struct Md5Ctx * md5ctx )

Initialise the MD5 computation.

Parameters

md5ctx MD5 context

RFC1321, 3.3: Step 3

Definition at line 261 of file md5.c.

{
  if (!md5ctx)
    return;
 
  md5ctx->A = 0x67452301;
  md5ctx->B = 0xefcdab89;
  md5ctx->C = 0x98badcfe;
  md5ctx->D = 0x10325476;
 
  md5ctx->total[0] = 0;
  md5ctx->total[1] = 0;
  md5ctx->buflen = 0;
}

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◆ mutt_md5_finish_ctx()

void * mutt_md5_finish_ctx	(	struct Md5Ctx *	md5ctx,
		void *	resbuf
	)

Process the remaining bytes in the buffer.

Parameters

md5ctx	MD5 context
resbuf	Buffer for result

Return values

ptr	Results buffer

Process the remaining bytes in the internal buffer and the usual prologue according to the standard and write the result to RESBUF.

Definition at line 285 of file md5.c.

{
  if (!md5ctx)
    return NULL;
 
  /* Take yet unprocessed bytes into account. */
  md5_uint32 bytes = md5ctx->buflen;
  size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
 
  /* Now count remaining bytes. */
  md5ctx->total[0] += bytes;
  if (md5ctx->total[0] < bytes)
    md5ctx->total[1]++; // LCOV_EXCL_LINE
 
  /* Put the 64-bit file length in *bits* at the end of the buffer. */
  md5ctx->buffer[size - 2] = SWAP(md5ctx->total[0] << 3);
  md5ctx->buffer[size - 1] = SWAP((md5ctx->total[1] << 3) | (md5ctx->total[0] >> 29));
 
  memcpy(&((char *) md5ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
 
  /* Process last bytes. */
  mutt_md5_process_block(md5ctx->buffer, size * 4, md5ctx);
 
  return mutt_md5_read_ctx(md5ctx, resbuf);
}

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◆ mutt_md5()

void * mutt_md5	(	const char *	str,
		void *	buf
	)

Calculate the MD5 hash of a NULL-terminated string.

Parameters

str	String to hash
buf	Buffer for result

Return values

ptr	Results buffer

Definition at line 317 of file md5.c.

{
  if (!str)
    return NULL;
 
  return mutt_md5_bytes(str, strlen(str), buf);
}

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◆ mutt_md5_bytes()

void * mutt_md5_bytes	(	const void *	buffer,
		size_t	len,
		void *	resbuf
	)

Calculate the MD5 hash of a buffer.

Parameters

buffer	Buffer to hash
len	Length of buffer
resbuf	Buffer for result

Return values

ptr	Results buffer

Compute MD5 message digest for LEN bytes beginning at Buffer. The result is always in little endian byte order, so that a byte-wise output yields to the wanted ASCII representation of the message digest.

Definition at line 336 of file md5.c.

{
  struct Md5Ctx md5ctx = { 0 };
 
  /* Initialize the computation context. */
  mutt_md5_init_ctx(&md5ctx);
 
  /* Process whole buffer but last len % 64 bytes. */
  mutt_md5_process_bytes(buffer, len, &md5ctx);
 
  /* Put result in desired memory area. */
  return mutt_md5_finish_ctx(&md5ctx, resbuf);
}

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◆ mutt_md5_process()

void mutt_md5_process	(	const char *	str,
		struct Md5Ctx *	md5ctx
	)

Process a NULL-terminated string.

Parameters

str	String to process
md5ctx	MD5 context

Definition at line 355 of file md5.c.

{
  if (!str)
    return;
 
  mutt_md5_process_bytes(str, strlen(str), md5ctx);
}

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◆ mutt_md5_process_bytes()

void mutt_md5_process_bytes	(	const void *	buf,
		size_t	buflen,
		struct Md5Ctx *	md5ctx
	)

Process a block of data.

Parameters

buf	Buffer to process
buflen	Length of buffer
md5ctx	MD5 context

Starting with the result of former calls of this function (or the initialization function update the context for the next BUFLEN bytes starting at Buffer. It is NOT required that BUFLEN is a multiple of 64.

Definition at line 373 of file md5.c.

{
  if (!buf || !md5ctx)
    return;
 
  /* When we already have some bits in our internal buffer concatenate both
   * inputs first. */
  if (md5ctx->buflen != 0)
  {
    size_t left_over = md5ctx->buflen;
    size_t add = ((128 - left_over) > buflen) ? buflen : (128 - left_over);
 
    memcpy(&((char *) md5ctx->buffer)[left_over], buf, add);
    md5ctx->buflen += add;
 
    if (md5ctx->buflen > 64)
    {
      mutt_md5_process_block(md5ctx->buffer, md5ctx->buflen & ~63, md5ctx);
 
      md5ctx->buflen &= 63;
      /* The regions in the following copy operation can't overlap. */
      memcpy(md5ctx->buffer, &((char *) md5ctx->buffer)[(left_over + add) & ~63],
             md5ctx->buflen);
    }
 
    buf = (const char *) buf + add;
    buflen -= add;
  }
 
  /* Process available complete blocks. */
  if (buflen >= 64)
  {
#if !defined(_STRING_ARCH_unaligned)
#define alignof(type)                                                          \
  offsetof(                                                                    \
      struct {                                                                 \
        char c;                                                                \
        type x;                                                                \
      },                                                                       \
      x)
#define UNALIGNED_P(p) (((size_t) p) % alignof(md5_uint32) != 0)
    if (UNALIGNED_P(buf))
    {
      while (buflen > 64)
      {
        mutt_md5_process_block(memcpy(md5ctx->buffer, buf, 64), 64, md5ctx);
        buf = (const char *) buf + 64;
        buflen -= 64;
      }
    }
    else
#endif
    {
      mutt_md5_process_block(buf, buflen & ~63, md5ctx);
      buf = (const char *) buf + (buflen & ~63);
      buflen &= 63;
    }
  }
 
  /* Move remaining bytes in internal buffer. */
  if (buflen > 0)
  {
    size_t left_over = md5ctx->buflen;
 
    memcpy(&((char *) md5ctx->buffer)[left_over], buf, buflen);
    left_over += buflen;
    if (left_over >= 64)
    { // LCOV_EXCL_START
      mutt_md5_process_block(md5ctx->buffer, 64, md5ctx);
      left_over -= 64;
      memmove(md5ctx->buffer, &md5ctx->buffer[16], left_over);
    } // LCOV_EXCL_STOP
    md5ctx->buflen = left_over;
  }
}

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◆ mutt_md5_toascii()

void mutt_md5_toascii	(	const void *	digest,
		char *	resbuf
	)

Convert a binary MD5 digest into ASCII Hexadecimal.

Parameters

digest	Binary MD5 digest
resbuf	Buffer for the ASCII result

Note: refbuf must be at least 33 bytes long.

Definition at line 456 of file md5.c.

{
  if (!digest || !resbuf)
    return;
 
  const unsigned char *c = digest;
  sprintf(resbuf, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
          c[0], c[1], c[2], c[3], c[4], c[5], c[6], c[7], c[8], c[9], c[10],
          c[11], c[12], c[13], c[14], c[15]);
}

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Variable Documentation

◆ fillbuf

const unsigned char fillbuf[64] = { 0x80, 0 }

static

This array contains the bytes used to pad the buffer to the next 64-byte boundary.

(RFC1321, 3.1: Step 1)

Definition at line 46 of file md5.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ SWAP

◆ FF

◆ FG

◆ FH

◆ FI

◆ OP [1/2]

◆ CYCLIC

◆ OP [2/2]

◆ alignof

◆ UNALIGNED_P

Function Documentation

◆ mutt_md5_process_block()

◆ set_uint32()

◆ mutt_md5_read_ctx()

◆ mutt_md5_init_ctx()

◆ mutt_md5_finish_ctx()

◆ mutt_md5()

◆ mutt_md5_bytes()

◆ mutt_md5_process()

◆ mutt_md5_process_bytes()

◆ mutt_md5_toascii()

Variable Documentation

◆ fillbuf