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tools: Add modules for MIME parsing and creating.

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* tools/mime-maker.c: New.
* tools/mime-maker.h: New.
* tools/mime-parser.c: New.
* tools/mime-parser.h: New.

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2016-06-29 11:02:36 +02:00
parent 9c67958c47
commit c334fa8df0
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
5 changed files with 1492 additions and 1 deletions
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/* mime-maker.c - Create MIME structures
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
#include "zb32.h"
#include "mime-maker.h"
/* An object to store an header. Also used for a list of headers. */
struct header_s
{
struct header_s *next;
char *value; /* Malloced value. */
char name[1]; /* Name. */
};
typedef struct header_s *header_t;
/* An object to store a MIME part. A part is the header plus the
* content (body). */
struct part_s
{
struct part_s *next; /* Next part in the current container. */
struct part_s *child; /* Child container. */
char *mediatype; /* Mediatype of the container (malloced). */
char *boundary; /* Malloced boundary string. */
header_t headers; /* List of headers. */
header_t *headers_tail;/* Address of last header in chain. */
size_t bodylen; /* Length of BODY. */
char *body; /* Malloced buffer with the body. This is the
* non-encoded value. */
};
typedef struct part_s *part_t;
/* Definition of the mime parser object. */
struct mime_maker_context_s
{
void *cookie; /* Cookie passed to all callbacks. */
unsigned int verbose:1; /* Enable verbose mode. */
unsigned int debug:1; /* Enable debug mode. */
part_t mail; /* The MIME tree. */
part_t current_part;
int boundary_counter; /* Used to create easy to read boundaries. */
char *boundary_suffix; /* Random string used in the boundaries. */
struct b64state *b64state; /* NULL or malloced Base64 decoder state. */
/* Helper to convey the output stream to recursive functions. */
estream_t outfp;
};
/* Create a new mime make object. COOKIE is a values woich will be
* used as first argument for all callbacks registered with this
* object. */
gpg_error_t
mime_maker_new (mime_maker_t *r_maker, void *cookie)
{
mime_maker_t ctx;
*r_maker = NULL;
ctx = xtrycalloc (1, sizeof *ctx);
if (!ctx)
return gpg_error_from_syserror ();
ctx->cookie = cookie;
*r_maker = ctx;
return 0;
}
static void
release_parts (part_t part)
{
while (part)
{
part_t partnext = part->next;
while (part->headers)
{
header_t hdrnext = part->headers->next;
xfree (part->headers);
part->headers = hdrnext;
}
release_parts (part->child);
xfree (part->mediatype);
xfree (part->boundary);
xfree (part->body);
xfree (part);
part = partnext;
}
}
/* Release a mime maker object. */
void
mime_maker_release (mime_maker_t ctx)
{
if (!ctx)
return;
release_parts (ctx->mail);
xfree (ctx->boundary_suffix);
xfree (ctx);
}
/* Set verbose and debug mode. */
void
mime_maker_set_verbose (mime_maker_t ctx, int level)
{
if (!level)
{
ctx->verbose = 0;
ctx->debug = 0;
}
else
{
ctx->verbose = 1;
if (level > 10)
ctx->debug = 1;
}
}
static void
dump_parts (part_t part, int level)
{
header_t hdr;
for (; part; part = part->next)
{
log_debug ("%*s[part]\n", level*2, "");
for (hdr = part->headers; hdr; hdr = hdr->next)
{
log_debug ("%*s%s: %s\n", level*2, "", hdr->name, hdr->value);
}
log_debug ("%*s[body %zu bytes]\n", level*2, "", part->bodylen);
if (part->child)
{
log_debug ("%*s[container]\n", level*2, "");
dump_parts (part->child, level+1);
}
}
}
/* Dump the mime tree for debugging. */
void
mime_maker_dump_tree (mime_maker_t ctx)
{
dump_parts (ctx->mail, 0);
}
/* Find the parent node for NEEDLE starting at ROOT. */
static part_t
find_parent (part_t root, part_t needle)
{
part_t node, n;
for (node = root->child; node; node = node->next)
{
if (node == needle)
return root;
if ((n = find_parent (node, needle)))
return n;
}
return NULL;
}
/* Create a boundary string. Outr codes is aware of the general
* structure of that string (gebins with "=-=") so that
* it can protect against accidently used boundaries within the
* content. */
static char *
generate_boundary (mime_maker_t ctx)
{
if (!ctx->boundary_suffix)
{
char buffer[12];
gcry_create_nonce (buffer, sizeof buffer);
ctx->boundary_suffix = zb32_encode (buffer, 8 * sizeof buffer);
if (!ctx->boundary_suffix)
return NULL;
}
ctx->boundary_counter++;
return es_bsprintf ("=-=%02d-%s=-=",
ctx->boundary_counter, ctx->boundary_suffix);
}
/* Ensure that the context has a MAIL and CURRENT_PART object and
* return the parent object if available */
static gpg_error_t
ensure_part (mime_maker_t ctx, part_t *r_parent)
{
if (!ctx->mail)
{
ctx->mail = xtrycalloc (1, sizeof *ctx->mail);
if (!ctx->mail)
return gpg_error_from_syserror ();
log_assert (!ctx->current_part);
ctx->current_part = ctx->mail;
ctx->current_part->headers_tail = &ctx->current_part->headers;
}
log_assert (ctx->current_part);
if (r_parent)
*r_parent = find_parent (ctx->mail, ctx->current_part);
return 0;
}
/* Transform a header name into a standard capitalized format.
* "Content-Type". Conversion stops at the colon. */
static void
capitalize_header_name (char *name)
{
unsigned char *p = name;
int first = 1;
/* Special cases first. */
if (!ascii_strcasecmp (name, "MIME-Version"))
{
strcpy (name, "MIME-Version");
return;
}
/* Regular cases. */
for (; *p && *p != ':'; p++)
{
if (*p == '-')
first = 1;
else if (first)
{
if (*p >= 'a' && *p <= 'z')
*p = *p - 'a' + 'A';
first = 0;
}
else if (*p >= 'A' && *p <= 'Z')
*p = *p - 'A' + 'a';
}
}
/* Check whether a header with NAME has already been set into PART.
* NAME must be in canonical capitalized format. Return true or
* false. */
static int
have_header (part_t part, const char *name)
{
header_t hdr;
for (hdr = part->headers; hdr; hdr = hdr->next)
if (!strcmp (hdr->name, name))
return 1;
return 0;
}
/* Helper to add a header to a part. */
static gpg_error_t
add_header (part_t part, const char *name, const char *value)
{
gpg_error_t err;
header_t hdr;
hdr = xtrymalloc (sizeof *hdr + strlen (name));
if (!hdr)
return gpg_error_from_syserror ();
hdr->next = NULL;
strcpy (hdr->name, name);
capitalize_header_name (hdr->name);
hdr->value = xtrystrdup (value);
if (!hdr->value)
{
err = gpg_error_from_syserror ();
xfree (hdr);
return err;
}
*part->headers_tail = hdr;
part->headers_tail = &hdr->next;
return 0;
}
/* Add a header with NAME and VALUE to the current mail. A LF in the
* VALUE will be handled automagically. If no container has been
* added, the header will be used for the regular mail headers and not
* for a MIME part. If the current part is in a container and a body
* has been added, we append a new part to the current container.
* Thus for a non-MIME mail the caller needs to call this function
* followed by a call to add a body. When adding a Content-Type the
* boundary parameter must not be included.
*/
gpg_error_t
mime_maker_add_header (mime_maker_t ctx, const char *name, const char *value)
{
gpg_error_t err;
part_t part, parent;
err = ensure_part (ctx, &parent);
if (err)
return err;
part = ctx->current_part;
if (part->body && !parent)
{
/* We already have a body but no parent. Adding another part is
* thus not possible. */
return gpg_error (GPG_ERR_CONFLICT);
}
if (part->body)
{
/* We already have a body and there is a parent. We now append
* a new part to the current container. */
part = xtrycalloc (1, sizeof *part);
if (!part)
return gpg_error_from_syserror ();
part->headers_tail = &part->headers;
log_assert (!ctx->current_part->next);
ctx->current_part->next = part;
ctx->current_part = part;
}
/* If no NAME and no VALUE has been given we do not add a header.
* This can be used to create a new part without any header. */
if (!name && !value)
return 0;
/* If we add Content-Type, make sure that we have a MIME-version
* header first; this simply looks better. */
if (!ascii_strcasecmp (name, "Content-Type")
&& !have_header (ctx->mail, "MIME-Version"))
{
err = add_header (ctx->mail, "MIME-Version", "1.0");
if (err)
return err;
}
return add_header (part, name, value);
}
/* Helper for mime_maker_add_{body,stream}. */
static gpg_error_t
add_body (mime_maker_t ctx, const void *data, size_t datalen)
{
gpg_error_t err;
part_t part, parent;
err = ensure_part (ctx, &parent);
if (err)
return err;
part = ctx->current_part;
if (part->body)
return gpg_error (GPG_ERR_CONFLICT);
part->body = xtrymalloc (datalen? datalen : 1);
if (!part->body)
return gpg_error_from_syserror ();
part->bodylen = datalen;
if (data)
memcpy (part->body, data, datalen);
return 0;
}
/* Add STRING as body to the mail or the current MIME container. A
* second call to this function is not allowed.
*
* FIXME: We may want to have an append_body to add more data to a body.
*/
gpg_error_t
mime_maker_add_body (mime_maker_t ctx, const char *string)
{
return add_body (ctx, string, strlen (string));
}
/* This is the same as mime_maker_add_body but takes a stream as
* argument. As of now the stream is copied to the MIME object but
* eventually we may delay that and read the stream only at the time
* it is needed. Note that the address of the stream object must be
* passed and that the ownership of the stream is transferred to this
* MIME object. To indicate the latter the function will store NULL
* at the ADDR_STREAM so that a caller can't use that object anymore
* except for es_fclose which accepts a NULL pointer. */
gpg_error_t
mime_maker_add_stream (mime_maker_t ctx, estream_t *stream_addr)
{
void *data;
size_t datalen;
es_rewind (*stream_addr);
if (es_fclose_snatch (*stream_addr, &data, &datalen))
return gpg_error_from_syserror ();
*stream_addr = NULL;
return add_body (ctx, data, datalen);
}
/* Add a new MIME container. The caller needs to provide the media
* and media-subtype in MEDIATYPE. If MEDIATYPE is NULL
* "multipart/mixed" is assumed. This function will then add a
* Content-Type header with that media type and an approriate boundary
* string to the parent part. */
gpg_error_t
mime_maker_add_container (mime_maker_t ctx, const char *mediatype)
{
gpg_error_t err;
part_t part;
if (!mediatype)
mediatype = "multipart/mixed";
err = ensure_part (ctx, NULL);
if (err)
return err;
part = ctx->current_part;
if (part->body)
return gpg_error (GPG_ERR_CONFLICT); /* There is already a body. */
if (part->child || part->mediatype || part->boundary)
return gpg_error (GPG_ERR_CONFLICT); /* There is already a container. */
/* If a content type has not yet been set, do it now. The boundary
* will be added while writing the headers. */
if (!have_header (ctx->mail, "Content-Type"))
{
err = add_header (ctx->mail, "Content-Type", mediatype);
if (err)
return err;
}
/* Create a child node. */
part->child = xtrycalloc (1, sizeof *part->child);
if (!part->child)
return gpg_error_from_syserror ();
part->child->headers_tail = &part->child->headers;
part->mediatype = xtrystrdup (mediatype);
if (!part->mediatype)
{
err = gpg_error_from_syserror ();
xfree (part->child);
part->child = NULL;
return err;
}
part->boundary = generate_boundary (ctx);
if (!part->boundary)
{
err = gpg_error_from_syserror ();
xfree (part->child);
part->child = NULL;
xfree (part->mediatype);
part->mediatype = NULL;
return err;
}
part = part->child;
ctx->current_part = part;
return 0;
}
/* Write the Content-Type header with the boundary value. */
static gpg_error_t
write_ct_with_boundary (mime_maker_t ctx,
const char *value, const char *boundary)
{
const char *s;
if (!*value)
return gpg_error (GPG_ERR_INV_VALUE); /* Empty string. */
for (s=value + strlen (value) - 1;
(s >= value
&& (*s == ' ' || *s == '\t' || *s == '\n'));
s--)
;
if (!(s >= value))
return gpg_error (GPG_ERR_INV_VALUE); /* Only spaces. */
/* Fixme: We should use a dedicated header write functions which
* properly wraps the header. */
es_fprintf (ctx->outfp, "Content-Type: %s%s\n\tboundary=\"%s\"\n",
value,
(*s == ';')? "":";",
boundary);
return 0;
}
/* Recursive worker for mime_maker_make. */
static gpg_error_t
write_tree (mime_maker_t ctx, part_t parent, part_t part)
{
gpg_error_t err;
header_t hdr;
for (; part; part = part->next)
{
for (hdr = part->headers; hdr; hdr = hdr->next)
{
if (part->child && !strcmp (hdr->name, "Content-Type"))
write_ct_with_boundary (ctx, hdr->value, part->boundary);
else
es_fprintf (ctx->outfp, "%s: %s\n", hdr->name, hdr->value);
}
es_fputc ('\n', ctx->outfp);
if (part->body)
{
if (es_write (ctx->outfp, part->body, part->bodylen, NULL))
return gpg_error_from_syserror ();
}
if (part->child)
{
log_assert (part->boundary);
if (es_fprintf (ctx->outfp, "\n--%s\n", part->boundary) < 0)
return gpg_error_from_syserror ();
err = write_tree (ctx, part, part->child);
if (err)
return err;
if (es_fprintf (ctx->outfp, "\n--%s--\n", part->boundary) < 0)
return gpg_error_from_syserror ();
}
if (part->next)
{
log_assert (parent && parent->boundary);
if (es_fprintf (ctx->outfp, "\n--%s\n", parent->boundary) < 0)
return gpg_error_from_syserror ();
}
}
return 0;
}
/* Add headers we always require. */
static gpg_error_t
add_missing_headers (mime_maker_t ctx)
{
gpg_error_t err;
if (!ctx->mail)
return gpg_error (GPG_ERR_NO_DATA);
if (!have_header (ctx->mail, "MIME-Version"))
{
/* Even if a Content-Type has never been set, we want to
* announce that we do MIME. */
err = add_header (ctx->mail, "MIME-Version", "1.0");
if (err)
goto leave;
}
if (!have_header (ctx->mail, "Date"))
{
char *p = rfctimestamp (make_timestamp ());
if (!p)
err = gpg_error_from_syserror ();
else
err = add_header (ctx->mail, "Date", p);
xfree (p);
if (err)
goto leave;
}
leave:
return err;
}
/* Create message from the tree MIME and write it to FP. Noet that
* the output uses only a LF and a later called sendmail(1) is
* expected to convert them to network line endings. */
gpg_error_t
mime_maker_make (mime_maker_t ctx, estream_t fp)
{
gpg_error_t err;
err = add_missing_headers (ctx);
if (err)
return err;
ctx->outfp = fp;
err = write_tree (ctx, NULL, ctx->mail);
ctx->outfp = NULL;
return err;
}

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/* mime-maker.h - Create MIME structures
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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/>.
*/
#ifndef GNUPG_MIME_MAKER_H
#define GNUPG_MIME_MAKER_H
struct mime_maker_context_s;
typedef struct mime_maker_context_s *mime_maker_t;
gpg_error_t mime_maker_new (mime_maker_t *r_ctx, void *cookie);
void mime_maker_release (mime_maker_t ctx);
void mime_maker_set_verbose (mime_maker_t ctx, int level);
void mime_maker_dump_tree (mime_maker_t ctx);
gpg_error_t mime_maker_add_header (mime_maker_t ctx,
const char *name, const char *value);
gpg_error_t mime_maker_add_body (mime_maker_t ctx, const char *string);
gpg_error_t mime_maker_add_stream (mime_maker_t ctx, estream_t *stream_addr);
gpg_error_t mime_maker_add_container (mime_maker_t ctx, const char *mediatype);
gpg_error_t mime_maker_make (mime_maker_t ctx, estream_t fp);
#endif /*GNUPG_MIME_MAKER_H*/

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/* mime-parser.c - Parse MIME structures (high level rfc822 parser).
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
#include "rfc822parse.h"
#include "mime-parser.h"
enum pgpmime_states
{
PGPMIME_NONE = 0,
PGPMIME_WAIT_ENCVERSION,
PGPMIME_IN_ENCVERSION,
PGPMIME_WAIT_ENCDATA,
PGPMIME_IN_ENCDATA,
PGPMIME_GOT_ENCDATA,
PGPMIME_WAIT_SIGNEDDATA,
PGPMIME_IN_SIGNEDDATA,
PGPMIME_WAIT_SIGNATURE,
PGPMIME_IN_SIGNATURE,
PGPMIME_GOT_SIGNATURE,
PGPMIME_INVALID
};
/* Definition of the mime parser object. */
struct mime_parser_context_s
{
void *cookie; /* Cookie passed to all callbacks. */
/* The callback to announce a new part. */
gpg_error_t (*new_part) (void *cookie,
const char *mediatype,
const char *mediasubtype);
/* The callback to return data of a part. */
gpg_error_t (*part_data) (void *cookie,
const void *data,
size_t datalen);
/* The callback to collect encrypted data. */
gpg_error_t (*collect_encrypted) (void *cookie, const char *data);
/* The callback to collect signed data. */
gpg_error_t (*collect_signeddata) (void *cookie, const char *data);
/* The callback to collect a signature. */
gpg_error_t (*collect_signature) (void *cookie, const char *data);
/* Helper to convey error codes from user callbacks. */
gpg_error_t err;
int nesting_level; /* The current nesting level. */
int hashing_at_level; /* The nesting level at which we are hashing. */
enum pgpmime_states pgpmime; /* Current PGP/MIME state. */
unsigned int delay_hashing:1;/* Helper for PGPMIME_IN_SIGNEDDATA. */
unsigned int want_part:1; /* Return the current part. */
unsigned int decode_part:2; /* Decode the part. 1 = QP, 2 = Base64. */
unsigned int verbose:1; /* Enable verbose mode. */
unsigned int debug:1; /* Enable debug mode. */
/* Flags to help with debug output. */
struct {
unsigned int n_skip; /* Skip showing these number of lines. */
unsigned int header:1; /* Show the header lines. */
unsigned int data:1; /* Show the data lines. */
unsigned int as_note:1; /* Show the next data line as a note. */
unsigned int boundary : 1;
} show;
struct b64state *b64state; /* NULL or malloced Base64 decoder state. */
/* A buffer for reading a mail line, */
char line[5000];
};
/* Print the event received by the parser for debugging. */
static void
show_message_parser_event (rfc822parse_event_t event)
{
const char *s;
switch (event)
{
case RFC822PARSE_OPEN: s= "Open"; break;
case RFC822PARSE_CLOSE: s= "Close"; break;
case RFC822PARSE_CANCEL: s= "Cancel"; break;
case RFC822PARSE_T2BODY: s= "T2Body"; break;
case RFC822PARSE_FINISH: s= "Finish"; break;
case RFC822PARSE_RCVD_SEEN: s= "Rcvd_Seen"; break;
case RFC822PARSE_LEVEL_DOWN: s= "Level_Down"; break;
case RFC822PARSE_LEVEL_UP: s= "Level_Up"; break;
case RFC822PARSE_BOUNDARY: s= "Boundary"; break;
case RFC822PARSE_LAST_BOUNDARY: s= "Last_Boundary"; break;
case RFC822PARSE_BEGIN_HEADER: s= "Begin_Header"; break;
case RFC822PARSE_PREAMBLE: s= "Preamble"; break;
case RFC822PARSE_EPILOGUE: s= "Epilogue"; break;
default: s= "[unknown event]"; break;
}
log_debug ("*** RFC822 event %s\n", s);
}
/* Do in-place decoding of quoted-printable data of LENGTH in BUFFER.
Returns the new length of the buffer and stores true at R_SLBRK if
the line ended with a soft line break; false is stored if not.
This fucntion asssumes that a complete line is passed in
buffer. */
static size_t
qp_decode (char *buffer, size_t length, int *r_slbrk)
{
char *d, *s;
if (r_slbrk)
*r_slbrk = 0;
/* Fixme: We should remove trailing white space first. */
for (s=d=buffer; length; length--)
{
if (*s == '=')
{
if (length > 2 && hexdigitp (s+1) && hexdigitp (s+2))
{
s++;
*(unsigned char*)d++ = xtoi_2 (s);
s += 2;
length -= 2;
}
else if (length > 2 && s[1] == '\r' && s[2] == '\n')
{
/* Soft line break. */
s += 3;
length -= 2;
if (r_slbrk && length == 1)
*r_slbrk = 1;
}
else if (length > 1 && s[1] == '\n')
{
/* Soft line break with only a Unix line terminator. */
s += 2;
length -= 1;
if (r_slbrk && length == 1)
*r_slbrk = 1;
}
else if (length == 1)
{
/* Soft line break at the end of the line. */
s += 1;
if (r_slbrk)
*r_slbrk = 1;
}
else
*d++ = *s++;
}
else
*d++ = *s++;
}
return d - buffer;
}
/* This function is called by parse_mail to communicate events. This
* callback communicates with the caller using a structure passed in
* OPAQUE. Should return 0 on success or set ERRNO and return -1. */
static int
parse_message_cb (void *opaque, rfc822parse_event_t event, rfc822parse_t msg)
{
mime_parser_t ctx = opaque;
const char *s;
int rc = 0;
if (ctx->debug)
show_message_parser_event (event);
if (event == RFC822PARSE_BEGIN_HEADER || event == RFC822PARSE_T2BODY)
{
/* We need to check here whether to start collecting signed data
* because attachments might come without header lines and thus
* we won't see the BEGIN_HEADER event. */
if (ctx->pgpmime == PGPMIME_WAIT_SIGNEDDATA)
{
if (ctx->debug)
log_debug ("begin_hash\n");
ctx->hashing_at_level = ctx->nesting_level;
ctx->pgpmime = PGPMIME_IN_SIGNEDDATA;
ctx->delay_hashing = 0;
}
}
if (event == RFC822PARSE_OPEN)
{
/* Initialize for a new message. */
ctx->show.header = 1;
}
else if (event == RFC822PARSE_T2BODY)
{
rfc822parse_field_t field;
ctx->want_part = 0;
ctx->decode_part = 0;
field = rfc822parse_parse_field (msg, "Content-Type", -1);
if (field)
{
const char *s1, *s2;
s1 = rfc822parse_query_media_type (field, &s2);
if (s1)
{
if (ctx->verbose)
log_debug ("h media: %*s%s %s\n",
ctx->nesting_level*2, "", s1, s2);
if (ctx->pgpmime == PGPMIME_WAIT_ENCVERSION)
{
if (!strcmp (s1, "application")
&& !strcmp (s2, "pgp-encrypted"))
{
if (ctx->debug)
log_debug ("c begin_encversion\n");
ctx->pgpmime = PGPMIME_IN_ENCVERSION;
}
else
{
log_error ("invalid PGP/MIME structure;"
" expected '%s', got '%s/%s'\n",
"application/pgp-encrypted", s1, s2);
ctx->pgpmime = PGPMIME_INVALID;
}
}
else if (ctx->pgpmime == PGPMIME_WAIT_ENCDATA)
{
if (!strcmp (s1, "application")
&& !strcmp (s2, "octet-stream"))
{
if (ctx->debug)
log_debug ("c begin_encdata\n");
ctx->pgpmime = PGPMIME_IN_ENCDATA;
}
else
{
log_error ("invalid PGP/MIME structure;"
" expected '%s', got '%s/%s'\n",
"application/octet-stream", s1, s2);
ctx->pgpmime = PGPMIME_INVALID;
}
}
else if (ctx->pgpmime == PGPMIME_WAIT_SIGNATURE)
{
if (!strcmp (s1, "application")
&& !strcmp (s2, "pgp-signature"))
{
if (ctx->debug)
log_debug ("c begin_signature\n");
ctx->pgpmime = PGPMIME_IN_SIGNATURE;
}
else
{
log_error ("invalid PGP/MIME structure;"
" expected '%s', got '%s/%s'\n",
"application/pgp-signature", s1, s2);
ctx->pgpmime = PGPMIME_INVALID;
}
}
else if (!strcmp (s1, "multipart")
&& !strcmp (s2, "encrypted"))
{
s = rfc822parse_query_parameter (field, "protocol", 0);
if (s)
{
if (ctx->debug)
log_debug ("h encrypted.protocol: %s\n", s);
if (!strcmp (s, "application/pgp-encrypted"))
{
if (ctx->pgpmime)
log_error ("note: "
"ignoring nested PGP/MIME signature\n");
else
ctx->pgpmime = PGPMIME_WAIT_ENCVERSION;
}
else if (ctx->verbose)
log_debug ("# this protocol is not supported\n");
}
}
else if (!strcmp (s1, "multipart")
&& !strcmp (s2, "signed"))
{
s = rfc822parse_query_parameter (field, "protocol", 1);
if (s)
{
if (ctx->debug)
log_debug ("h signed.protocol: %s\n", s);
if (!strcmp (s, "application/pgp-signature"))
{
if (ctx->pgpmime)
log_error ("note: "
"ignoring nested PGP/MIME signature\n");
else
ctx->pgpmime = PGPMIME_WAIT_SIGNEDDATA;
}
else if (ctx->verbose)
log_debug ("# this protocol is not supported\n");
}
}
else if (ctx->new_part)
{
ctx->err = ctx->new_part (ctx->cookie, s1, s2);
if (!ctx->err)
ctx->want_part = 1;
else if (gpg_err_code (ctx->err) == GPG_ERR_FALSE)
ctx->err = 0;
else if (gpg_err_code (ctx->err) == GPG_ERR_TRUE)
{
ctx->want_part = ctx->decode_part = 1;
ctx->err = 0;
}
}
}
else
{
if (ctx->debug)
log_debug ("h media: %*s none\n", ctx->nesting_level*2, "");
if (ctx->new_part)
{
ctx->err = ctx->new_part (ctx->cookie, "", "");
if (!ctx->err)
ctx->want_part = 1;
else if (gpg_err_code (ctx->err) == GPG_ERR_FALSE)
ctx->err = 0;
else if (gpg_err_code (ctx->err) == GPG_ERR_TRUE)
{
ctx->want_part = ctx->decode_part = 1;
ctx->err = 0;
}
}
}
rfc822parse_release_field (field);
}
else
{
if (ctx->verbose)
log_debug ("h media: %*stext plain [assumed]\n",
ctx->nesting_level*2, "");
if (ctx->new_part)
{
ctx->err = ctx->new_part (ctx->cookie, "text", "plain");
if (!ctx->err)
ctx->want_part = 1;
else if (gpg_err_code (ctx->err) == GPG_ERR_FALSE)
ctx->err = 0;
else if (gpg_err_code (ctx->err) == GPG_ERR_TRUE)
{
ctx->want_part = ctx->decode_part = 1;
ctx->err = 0;
}
}
}
/* Figure out the encoding if needed. */
if (ctx->decode_part)
{
char *value;
size_t valueoff;
ctx->decode_part = 0; /* Fallback for unknown encoding. */
value = rfc822parse_get_field (msg, "Content-Transfer-Encoding", -1,
&valueoff);
if (value)
{
if (!stricmp (value+valueoff, "quoted-printable"))
ctx->decode_part = 1;
else if (!stricmp (value+valueoff, "base64"))
{
ctx->decode_part = 2;
if (ctx->b64state)
b64dec_finish (ctx->b64state); /* Reuse state. */
else
{
ctx->b64state = xtrymalloc (sizeof *ctx->b64state);
if (!ctx->b64state)
rc = gpg_error_from_syserror ();
}
if (!rc)
rc = b64dec_start (ctx->b64state, NULL);
}
free (value); /* Right, we need a plain free. */
}
}
ctx->show.header = 0;
ctx->show.data = 1;
ctx->show.n_skip = 1;
}
else if (event == RFC822PARSE_PREAMBLE)
ctx->show.as_note = 1;
else if (event == RFC822PARSE_LEVEL_DOWN)
{
if (ctx->debug)
log_debug ("b down\n");
ctx->nesting_level++;
}
else if (event == RFC822PARSE_LEVEL_UP)
{
if (ctx->debug)
log_debug ("b up\n");
if (ctx->nesting_level)
ctx->nesting_level--;
else
log_error ("invalid structure (bad nesting level)\n");
}
else if (event == RFC822PARSE_BOUNDARY || event == RFC822PARSE_LAST_BOUNDARY)
{
ctx->show.data = 0;
ctx->show.boundary = 1;
if (event == RFC822PARSE_BOUNDARY)
{
ctx->show.header = 1;
ctx->show.n_skip = 1;
if (ctx->debug)
log_debug ("b part\n");
}
else if (ctx->debug)
log_debug ("b last\n");
if (ctx->pgpmime == PGPMIME_IN_ENCDATA)
{
if (ctx->debug)
log_debug ("c end_encdata\n");
ctx->pgpmime = PGPMIME_GOT_ENCDATA;
/* FIXME: We should assert (event == LAST_BOUNDARY). */
}
else if (ctx->pgpmime == PGPMIME_IN_SIGNEDDATA
&& ctx->nesting_level == ctx->hashing_at_level)
{
if (ctx->debug)
log_debug ("c end_hash\n");
ctx->pgpmime = PGPMIME_WAIT_SIGNATURE;
if (ctx->collect_signeddata)
ctx->err = ctx->collect_signeddata (ctx->cookie, NULL);
}
else if (ctx->pgpmime == PGPMIME_IN_SIGNATURE)
{
if (ctx->debug)
log_debug ("c end_signature\n");
ctx->pgpmime = PGPMIME_GOT_SIGNATURE;
/* FIXME: We should assert (event == LAST_BOUNDARY). */
}
else if (ctx->want_part)
{
if (ctx->part_data)
{
/* FIXME: We may need to flush things. */
ctx->err = ctx->part_data (ctx->cookie, NULL, 0);
}
ctx->want_part = 0;
}
}
return rc;
}
/* Create a new mime parser object. COOKIE is a values which will be
* used as first argument for all callbacks registered with this
* parser object. */
gpg_error_t
mime_parser_new (mime_parser_t *r_parser, void *cookie)
{
mime_parser_t ctx;
*r_parser = NULL;
ctx = xtrycalloc (1, sizeof *ctx);
if (!ctx)
return gpg_error_from_syserror ();
ctx->cookie = cookie;
*r_parser = ctx;
return 0;
}
/* Release a mime parser object. */
void
mime_parser_release (mime_parser_t ctx)
{
if (!ctx)
return;
if (ctx->b64state)
{
b64dec_finish (ctx->b64state);
xfree (ctx->b64state);
}
xfree (ctx);
}
/* Set verbose and debug mode. */
void
mime_parser_set_verbose (mime_parser_t ctx, int level)
{
if (!level)
{
ctx->verbose = 0;
ctx->debug = 0;
}
else
{
ctx->verbose = 1;
if (level > 10)
ctx->debug = 1;
}
}
/* Set the callback used to announce a new part. It will be called
* with the media type and media subtype of the part. If no
* Content-type header was given both values are the empty string.
* The callback should return 0 on success or an error code. The
* error code GPG_ERR_FALSE indicates that the caller is not
* interested in the part and data shall not be returned via a
* registered part_data callback. The error code GPG_ERR_TRUE
* indicates that the parts shall be redurned in decoded format
* (i.e. base64 or QP encoding is removed). */
void
mime_parser_set_new_part (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *mediatype,
const char *mediasubtype))
{
ctx->new_part = fnc;
}
/* Set the callback used to return the data of a part to the caller.
* The end of the part is indicated by passing NUL for DATA. */
void
mime_parser_set_part_data (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const void *data,
size_t datalen))
{
ctx->part_data = fnc;
}
/* Set the callback to collect encrypted data. A NULL passed to the
* callback indicates the end of the encrypted data; the callback may
* then decrypt the collected data. */
void
mime_parser_set_collect_encrypted (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data))
{
ctx->collect_encrypted = fnc;
}
/* Set the callback to collect signed data. A NULL passed to the
* callback indicates the end of the signed data. */
void
mime_parser_set_collect_signeddata (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data))
{
ctx->collect_signeddata = fnc;
}
/* Set the callback to collect the signature. A NULL passed to the
* callback indicates the end of the signature; the callback may the
* verify the signature. */
void
mime_parser_set_collect_signature (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data))
{
ctx->collect_signature = fnc;
}
/* Read and parse a message from FP and call the appropriate
* callbacks. */
gpg_error_t
mime_parser_parse (mime_parser_t ctx, estream_t fp)
{
gpg_error_t err;
rfc822parse_t msg = NULL;
unsigned int lineno = 0;
size_t length, nbytes;
char *line;
line = ctx->line;
msg = rfc822parse_open (parse_message_cb, ctx);
if (!msg)
{
err = gpg_error_from_syserror ();
log_error ("can't open mail parser: %s", gpg_strerror (err));
goto leave;
}
/* Fixme: We should not use fgets because it can't cope with
embedded nul characters. */
while (es_fgets (ctx->line, sizeof (ctx->line), fp))
{
lineno++;
if (lineno == 1 && !strncmp (line, "From ", 5))
continue; /* We better ignore a leading From line. */
length = strlen (line);
if (length && line[length - 1] == '\n')
line[--length] = 0;
else
log_error ("mail parser detected too long or"
" non terminated last line (lnr=%u)\n", lineno);
if (length && line[length - 1] == '\r')
line[--length] = 0;
ctx->err = 0;
if (rfc822parse_insert (msg, line, length))
{
err = gpg_error_from_syserror ();
log_error ("mail parser failed: %s", gpg_strerror (err));
goto leave;
}
if (ctx->err)
{
/* Error from a callback detected. */
err = ctx->err;
goto leave;
}
/* Debug output. Note that the boundary is shown before n_skip
* is evaluated. */
if (ctx->show.boundary)
{
if (ctx->debug)
log_debug ("# Boundary: %s\n", line);
ctx->show.boundary = 0;
}
if (ctx->show.n_skip)
ctx->show.n_skip--;
else if (ctx->show.data)
{
if (ctx->show.as_note)
{
if (ctx->verbose)
log_debug ("# Note: %s\n", line);
ctx->show.as_note = 0;
}
else if (ctx->debug)
log_debug ("# Data: %s\n", line);
}
else if (ctx->show.header && ctx->verbose)
log_debug ("# Header: %s\n", line);
if (ctx->pgpmime == PGPMIME_IN_ENCVERSION)
{
trim_trailing_spaces (line);
if (!*line)
; /* Skip empty lines. */
else if (!strcmp (line, "Version: 1"))
ctx->pgpmime = PGPMIME_WAIT_ENCDATA;
else
{
log_error ("invalid PGP/MIME structure;"
" garbage in pgp-encrypted part ('%s')\n", line);
ctx->pgpmime = PGPMIME_INVALID;
}
}
else if (ctx->pgpmime == PGPMIME_IN_ENCDATA)
{
if (ctx->collect_encrypted)
{
err = ctx->collect_encrypted (ctx->cookie, line);
if (!err)
err = ctx->collect_encrypted (ctx->cookie, "\r\n");
if (err)
goto leave;
}
}
else if (ctx->pgpmime == PGPMIME_GOT_ENCDATA)
{
ctx->pgpmime = PGPMIME_NONE;
if (ctx->collect_encrypted)
ctx->collect_encrypted (ctx->cookie, NULL);
}
else if (ctx->pgpmime == PGPMIME_IN_SIGNEDDATA)
{
/* If we are processing signed data, store the signed data.
* We need to delay the hashing of the CR/LF because the
* last line ending belongs to the next boundary. This is
* the reason why we can't use the PGPMIME state as a
* condition. */
if (ctx->debug)
log_debug ("# hashing %s'%s'\n",
ctx->delay_hashing? "CR,LF+":"", line);
if (ctx->collect_signeddata)
{
if (ctx->delay_hashing)
ctx->collect_signeddata (ctx->cookie, "\r\n");
ctx->collect_signeddata (ctx->cookie, line);
}
ctx->delay_hashing = 1;
}
else if (ctx->pgpmime == PGPMIME_IN_SIGNATURE)
{
if (ctx->collect_signeddata)
{
ctx->collect_signature (ctx->cookie, line);
ctx->collect_signature (ctx->cookie, "\r\n");
}
}
else if (ctx->pgpmime == PGPMIME_GOT_SIGNATURE)
{
ctx->pgpmime = PGPMIME_NONE;
if (ctx->collect_signeddata)
ctx->collect_signature (ctx->cookie, NULL);
}
else if (ctx->want_part)
{
if (ctx->part_data)
{
if (ctx->decode_part == 1)
{
length = qp_decode (line, length, NULL);
}
else if (ctx->decode_part == 2)
{
log_assert (ctx->b64state);
err = b64dec_proc (ctx->b64state, line, length, &nbytes);
if (err)
goto leave;
length = nbytes;
}
err = ctx->part_data (ctx->cookie, line, length);
if (err)
goto leave;
}
}
}
rfc822parse_close (msg);
msg = NULL;
err = 0;
leave:
rfc822parse_cancel (msg);
return err;
}

52
tools/mime-parser.h Normal file
View File

@ -0,0 +1,52 @@
/* mime-parser.h - Parse MIME structures (high level rfc822 parser).
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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/>.
*/
#ifndef GNUPG_MIME_PARSER_H
#define GNUPG_MIME_PARSER_H
struct mime_parser_context_s;
typedef struct mime_parser_context_s *mime_parser_t;
gpg_error_t mime_parser_new (mime_parser_t *r_ctx, void *cookie);
void mime_parser_release (mime_parser_t ctx);
void mime_parser_set_verbose (mime_parser_t ctx, int level);
void mime_parser_set_new_part (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *mediatype,
const char *mediasubtype));
void mime_parser_set_part_data (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const void *data,
size_t datalen));
void mime_parser_set_collect_encrypted (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data));
void mime_parser_set_collect_signeddata (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data));
void mime_parser_set_collect_signature (mime_parser_t ctx,
gpg_error_t (*fnc) (void *cookie,
const char *data));
gpg_error_t mime_parser_parse (mime_parser_t ctx, estream_t fp);
#endif /*GNUPG_MIME_PARSER_H*/

2
tools/rfc822parse.h
View File

@ -1,6 +1,6 @@
/* rfc822parse.h - Simple mail and MIME parser
* Copyright (C) 1999 Werner Koch, Duesseldorf
* Copyright (C) 2003, g10 Code GmbH
* Copyright (C) 2003 g10 Code GmbH
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License