pgppacket.c File Reference

Parse PGP data packets. More...

#include "config.h"
#include <stdbool.h>
#include <stdio.h>
#include "mutt/lib.h"
#include "pgppacket.h"

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Macros
#define	CHUNK_SIZE   1024
	Amount of data to read at once.

Functions
static int	read_material (size_t material, size_t *used, FILE *fp)
	Read PGP data into a buffer.
unsigned char *	pgp_read_packet (FILE *fp, size_t *len)
	Read a PGP packet from a file.
void	pgp_release_packet (void)
	Free the cached PGP packet.

Variables
static unsigned char *	PacketBuf = NULL
	Cached PGP data packet.
static size_t	PacketBufLen = 0
	Length of cached packet.

Detailed Description

Parse PGP data packets.

Authors

• Richard Russon
• Pietro Cerutti

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 pgppacket.c.

Macro Definition Documentation

CHUNK_SIZE

#define CHUNK_SIZE   1024

Amount of data to read at once.

Definition at line 36 of file pgppacket.c.

Function Documentation

read_material()

static int read_material ( size_t  material, size_t *  used, FILE *  fp  )

static

Read PGP data into a buffer.

Parameters

[in]	material	Number of bytes to read
[in,out]	used	Number of bytes already read
[in]	fp	File to read from

Return values

0	Success
-1	Failure (see errno)

This function uses a cache to store the data: PacketBuf, PacketBufLen.

Definition at line 51 of file pgppacket.c.

{
  if ((*used + material) >= PacketBufLen)
  {
    PacketBufLen = *used + material + CHUNK_SIZE;
 
    mutt_mem_realloc(&PacketBuf, PacketBufLen);
  }
 
  if (fread(PacketBuf + *used, 1, material, fp) < material)
  {
    mutt_perror("fread");
    return -1;
  }
 
  *used += material;
  return 0;
}

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pgp_read_packet()

unsigned char * pgp_read_packet	(	FILE *	fp,
		size_t *	len
	)

Read a PGP packet from a file.

Parameters

[in]	fp	File to read from
[out]	len	Number of bytes read

Return values

ptr	PGP data packet

This function uses a cache to store the data: PacketBuf, PacketBufLen.

Definition at line 78 of file pgppacket.c.

{
  size_t used = 0;
  LOFF_T startpos;
  unsigned char ctb;
  unsigned char b;
  size_t material;
 
  startpos = ftello(fp);
  if (startpos < 0)
    return NULL;
 
  if (PacketBufLen == 0)
  {
    PacketBufLen = CHUNK_SIZE;
    PacketBuf = mutt_mem_malloc(PacketBufLen);
  }
 
  if (fread(&ctb, 1, 1, fp) < 1)
  {
    if (!feof(fp))
      mutt_perror("fread");
    goto bail;
  }
 
  if (!(ctb & 0x80))
  {
    goto bail;
  }
 
  if (ctb & 0x40) /* handle PGP 5.0 packets. */
  {
    bool partial = false;
    PacketBuf[0] = ctb;
    used++;
 
    do
    {
      if (fread(&b, 1, 1, fp) < 1)
      {
        mutt_perror("fread");
        goto bail;
      }
 
      if (b < 192)
      {
        material = b;
        partial = false;
      }
      else if (b <= 223)
      {
        material = (b - 192) * 256;
        if (fread(&b, 1, 1, fp) < 1)
        {
          mutt_perror("fread");
          goto bail;
        }
        material += b + 192;
        partial = false;
      }
      else if (b < 255)
      {
        material = 1 << (b & 0x1f);
        partial = true;
      }
      else /* b == 255 */
      {
        unsigned char buf[4];
        if (fread(buf, 4, 1, fp) < 1)
        {
          mutt_perror("fread");
          goto bail;
        }
        material = (size_t) buf[0] << 24;
        material |= buf[1] << 16;
        material |= buf[2] << 8;
        material |= buf[3];
        partial = false;
      }
 
      if (read_material(material, &used, fp) == -1)
        goto bail;
 
    } while (partial);
  }
  else /* Old-Style PGP */
  {
    int bytes = 0;
    PacketBuf[0] = 0x80 | ((ctb >> 2) & 0x0f);
    used++;
 
    switch (ctb & 0x03)
    {
      case 0:
      {
        if (fread(&b, 1, 1, fp) < 1)
        {
          mutt_perror("fread");
          goto bail;
        }
 
        material = b;
        break;
      }
 
      case 1:
        bytes = 2;
        FALLTHROUGH;
 
      case 2:
      {
        if (!bytes)
          bytes = 4;
 
        material = 0;
 
        for (int i = 0; i < bytes; i++)
        {
          if (fread(&b, 1, 1, fp) < 1)
          {
            mutt_perror("fread");
            goto bail;
          }
 
          material = (material << 8) + b;
        }
        break;
      }
 
      default:
        goto bail;
    }
 
    if (read_material(material, &used, fp) == -1)
      goto bail;
  }
 
  if (len)
    *len = used;
 
  return PacketBuf;
 
bail:
 
  (void) mutt_file_seek(fp, startpos, SEEK_SET);
  return NULL;
}

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pgp_release_packet()

void pgp_release_packet

(

void

)

Free the cached PGP packet.

Free the data stored in PacketBuf.

Definition at line 231 of file pgppacket.c.

{
  PacketBufLen = 0;
  FREE(&PacketBuf);
}

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Variable Documentation

PacketBuf

unsigned char* PacketBuf = NULL

static

Cached PGP data packet.

Definition at line 38 of file pgppacket.c.

PacketBufLen

size_t PacketBufLen = 0

static

Length of cached packet.

Definition at line 39 of file pgppacket.c.