* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 */
-/* License: GPL */
+/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2015
+ * License: GPL
+ * Copyright (c) The Exim Maintainers 2015 - 2018
+ */
#include "exim.h"
#ifdef WITH_CONTENT_SCAN /* entire file */
FILE *mime_stream = NULL;
uschar *mime_current_boundary = NULL;
+static mime_header mime_header_list[] = {
+ /* name namelen value */
+ { US"content-type:", 13, &mime_content_type },
+ { US"content-disposition:", 20, &mime_content_disposition },
+ { US"content-transfer-encoding:", 26, &mime_content_transfer_encoding },
+ { US"content-id:", 11, &mime_content_id },
+ { US"content-description:", 20, &mime_content_description }
+};
+
+static int mime_header_list_size = nelem(mime_header_list);
+
+static mime_parameter mime_parameter_list[] = {
+ /* name namelen value */
+ { US"name=", 5, &mime_filename },
+ { US"filename=", 9, &mime_filename },
+ { US"charset=", 8, &mime_charset },
+ { US"boundary=", 9, &mime_boundary }
+};
+
+
/*************************************************
* set MIME anomaly level + text *
*************************************************/
/* Small wrapper to set the two expandables which
give info on detected "problems" in MIME
- encodings. Those are defined in mime.h. */
+ encodings. Indexes are defined in mime.h. */
void
-mime_set_anomaly(int level, const char *text)
+mime_set_anomaly(int idx)
{
- mime_anomaly_level = level;
- mime_anomaly_text = CUS text;
+struct anom {
+ int level;
+ const uschar * text;
+} anom[] = { {1, CUS"Broken Quoted-Printable encoding detected"},
+ {2, CUS"Broken BASE64 encoding detected"} };
+
+mime_anomaly_level = anom[idx].level;
+mime_anomaly_text = anom[idx].text;
}
0-255 - char to write
*/
-uschar *
+static uschar *
mime_decode_qp_char(uschar *qp_p, int *c)
{
uschar *initial_pos = qp_p;
}
-/* decode base64 MIME part */
-static ssize_t
-mime_decode_base64(FILE* in, FILE* out, uschar* boundary)
-{
- uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH];
- uschar *ipos, *opos;
- ssize_t len, size = 0;
- int bytestate = 0;
-
- opos = obuf;
-
- while (Ufgets(ibuf, MIME_MAX_LINE_LENGTH, in) != NULL)
- {
- if (boundary != NULL
- && Ustrncmp(ibuf, "--", 2) == 0
- && Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0
- )
- break;
-
- for (ipos = ibuf ; *ipos != '\r' && *ipos != '\n' && *ipos != 0; ++ipos)
- {
- if (*ipos == '=') /* skip padding */
- {
- ++bytestate;
- continue;
- }
- if (mime_b64[*ipos] == 128) /* skip bad characters */
- {
- mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64);
- continue;
- }
-
- /* simple state-machine */
- switch((bytestate++) & 3)
- {
- case 0:
- *opos = mime_b64[*ipos] << 2;
- break;
- case 1:
- *opos |= mime_b64[*ipos] >> 4;
- ++opos;
- *opos = mime_b64[*ipos] << 4;
- break;
- case 2:
- *opos |= mime_b64[*ipos] >> 2;
- ++opos;
- *opos = mime_b64[*ipos] << 6;
- break;
- case 3:
- *opos |= mime_b64[*ipos];
- ++opos;
- break;
- } /* switch */
- } /* for */
-
- /* something to write? */
- len = opos - obuf;
- if (len > 0)
- {
- if (fwrite(obuf, 1, len, out) != len) return -1; /* error */
- size += len;
- /* copy incomplete last byte to start of obuf, where we continue */
- if ((bytestate & 3) != 0)
- *obuf = *opos;
- opos = obuf;
- }
- } /* while */
-
- /* write out last byte if it was incomplete */
- if (bytestate & 3)
- {
- if (fwrite(obuf, 1, 1, out) != 1) return -1;
- ++size;
- }
-
- return size;
-}
-
/* decode quoted-printable MIME part */
static ssize_t
{
/* Error from decoder. ipos is unchanged. */
mime_set_anomaly(MIME_ANOMALY_BROKEN_QP);
- *opos = '=';
- ++opos;
+ *opos++ = '=';
++ipos;
}
else if (decode_qp_result == -1)
break;
else if (decode_qp_result >= 0)
- {
- *opos = decode_qp_result;
- ++opos;
- }
+ *opos++ = decode_qp_result;
}
else
- {
- *opos = *ipos;
- ++opos;
- ++ipos;
- }
+ *opos++ = *ipos++;
}
/* something to write? */
len = opos - obuf;
}
-FILE *
+/*
+ * Return open filehandle for combo of path and file.
+ * Side-effect: set mime_decoded_filename, to copy in allocated mem
+ */
+static FILE *
mime_get_decode_file(uschar *pname, uschar *fname)
{
-FILE *f = NULL;
-uschar *filename;
-
-filename = (uschar *)malloc(2048);
-
if (pname && fname)
- {
- (void)string_format(filename, 2048, "%s/%s", pname, fname);
- f = modefopen(filename,"wb+",SPOOL_MODE);
- }
+ mime_decoded_filename = string_sprintf("%s/%s", pname, fname);
else if (!pname)
- f = modefopen(fname,"wb+",SPOOL_MODE);
+ mime_decoded_filename = string_copy(fname);
else if (!fname)
{
int file_nr = 0;
do
{
struct stat mystat;
- (void)string_format(filename, 2048,
- "%s/%s-%05u", pname, message_id, file_nr++);
+ mime_decoded_filename = string_sprintf("%s/%s-%05u", pname, message_id, file_nr++);
/* security break */
if (file_nr >= 1024)
break;
- result = stat(CS filename, &mystat);
+ result = stat(CS mime_decoded_filename, &mystat);
} while(result != -1);
-
- f = modefopen(filename, "wb+", SPOOL_MODE);
}
-/* set expansion variable */
-mime_decoded_filename = filename;
-
-return f;
+return modefopen(mime_decoded_filename, "wb+", SPOOL_MODE);
}
{
int sep = 0;
const uschar *list = *listptr;
-uschar *option;
-uschar option_buffer[1024];
-uschar decode_path[1024];
+uschar * option;
+uschar * decode_path;
FILE *decode_file = NULL;
long f_pos = 0;
ssize_t size_counter = 0;
ssize_t (*decode_function)(FILE*, FILE*, uschar*);
-if (mime_stream == NULL)
+if (!mime_stream || (f_pos = ftell(mime_stream)) < 0)
return FAIL;
-f_pos = ftell(mime_stream);
-
/* build default decode path (will exist since MBOX must be spooled up) */
-(void)string_format(decode_path,1024,"%s/scan/%s",spool_directory,message_id);
+decode_path = string_sprintf("%s/scan/%s", spool_directory, message_id);
/* try to find 1st option */
-if ((option = string_nextinlist(&list, &sep,
- option_buffer,
- sizeof(option_buffer))) != NULL)
+if ((option = string_nextinlist(&list, &sep, NULL, 0)))
{
/* parse 1st option */
- if ( (Ustrcmp(option,"false") == 0) || (Ustrcmp(option,"0") == 0) )
+ if ((Ustrcmp(option,"false") == 0) || (Ustrcmp(option,"0") == 0))
/* explicitly no decoding */
return FAIL;
size_counter = decode_function(mime_stream, decode_file, mime_current_boundary);
clearerr(mime_stream);
-fseek(mime_stream, f_pos, SEEK_SET);
+if (fseek(mime_stream, f_pos, SEEK_SET))
+ return DEFER;
if (fclose(decode_file) != 0 || size_counter < 0)
return DEFER;
return OK;
}
-int
+
+static int
mime_get_header(FILE *f, uschar *header)
{
int c = EOF;
}
+static void
+mime_vars_reset(void)
+{
+mime_anomaly_level = 0;
+mime_anomaly_text = NULL;
+mime_boundary = NULL;
+mime_charset = NULL;
+mime_decoded_filename = NULL;
+mime_filename = NULL;
+mime_content_description = NULL;
+mime_content_disposition = NULL;
+mime_content_id = NULL;
+mime_content_transfer_encoding = NULL;
+mime_content_type = NULL;
+mime_is_multipart = 0;
+mime_content_size = 0;
+}
+
+
+/* Grab a parameter value, dealing with quoting.
+
+Arguments:
+ str Input string. Updated on return to point to terminating ; or NUL
+
+Return:
+ Allocated string with parameter value
+*/
+static uschar *
+mime_param_val(uschar ** sp)
+{
+uschar * s = *sp;
+gstring * val = NULL;
+
+/* debug_printf_indent(" considering paramval '%s'\n", s); */
+
+while (*s && *s != ';') /* ; terminates */
+ if (*s == '"')
+ {
+ s++; /* skip opening " */
+ while (*s && *s != '"') /* " protects ; */
+ val = string_catn(val, s++, 1);
+ if (*s) s++; /* skip closing " */
+ }
+ else
+ val = string_catn(val, s++, 1);
+*sp = s;
+return string_from_gstring(val);
+}
+
+static uschar *
+mime_next_semicolon(uschar * s)
+{
+while (*s && *s != ';') /* ; terminates */
+ if (*s == '"')
+ {
+ s++; /* skip opening " */
+ while (*s && *s != '"') /* " protects ; */
+ s++;
+ if (*s) s++; /* skip closing " */
+ }
+ else
+ s++;
+return s;
+}
+
+
+static uschar *
+rfc2231_to_2047(const uschar * fname, const uschar * charset, int * len)
+{
+gstring * val = string_catn(NULL, US"=?", 2);
+uschar c;
+
+if (charset)
+ val = string_cat(val, charset);
+val = string_catn(val, US"?Q?", 3);
+
+while ((c = *fname))
+ if (c == '%' && isxdigit(fname[1]) && isxdigit(fname[2]))
+ {
+ val = string_catn(val, US"=", 1);
+ val = string_catn(val, ++fname, 2);
+ fname += 2;
+ }
+ else
+ val = string_catn(val, fname++, 1);
+
+val = string_catn(val, US"?=", 2);
+*len = val->ptr;
+return string_from_gstring(val);
+}
+
+
int
mime_acl_check(uschar *acl, FILE *f, struct mime_boundary_context *context,
- uschar **user_msgptr, uschar **log_msgptr)
+ uschar **user_msgptr, uschar **log_msgptr)
{
int rc = OK;
-uschar *header = NULL;
+uschar * header = NULL;
struct mime_boundary_context nested_context;
/* reserve a line buffer to work in */
-if (!(header = (uschar *)malloc(MIME_MAX_HEADER_SIZE+1)))
- {
- log_write(0, LOG_PANIC,
- "MIME ACL: can't allocate %d bytes of memory.", MIME_MAX_HEADER_SIZE+1);
- return DEFER;
- }
+header = store_get(MIME_MAX_HEADER_SIZE+1);
/* Not actually used at the moment, but will be vital to fixing
* some RFC 2046 nonconformance later... */
while(1)
{
/* reset all per-part mime variables */
- mime_anomaly_level = 0;
- mime_anomaly_text = NULL;
- mime_boundary = NULL;
- mime_charset = NULL;
- mime_decoded_filename = NULL;
- mime_filename = NULL;
- mime_content_description = NULL;
- mime_content_disposition = NULL;
- mime_content_id = NULL;
- mime_content_transfer_encoding = NULL;
- mime_content_type = NULL;
- mime_is_multipart = 0;
- mime_content_size = 0;
-
- /*
- If boundary is null, we assume that *f is positioned on the start of headers (for example,
- at the very beginning of a message.
- If a boundary is given, we must first advance to it to reach the start of the next header
- block.
- */
+ mime_vars_reset();
+
+ /* If boundary is null, we assume that *f is positioned on the start of
+ headers (for example, at the very beginning of a message. If a boundary is
+ given, we must first advance to it to reach the start of the next header
+ block. */
/* NOTE -- there's an error here -- RFC2046 specifically says to
* check for outer boundaries. This code doesn't do that, and
* (I have moved partway towards adding support, however, by adding
* a "parent" field to my new boundary-context structure.)
*/
- if (context != NULL)
+ if (context) for (;;)
{
- while(fgets(CS header, MIME_MAX_HEADER_SIZE, f))
+ if (!fgets(CS header, MIME_MAX_HEADER_SIZE, f))
{
- /* boundary line must start with 2 dashes */
- if ( Ustrncmp(header, "--", 2) == 0
- && Ustrncmp(header+2, context->boundary, Ustrlen(context->boundary)) == 0)
- {
- /* found boundary */
- if (Ustrncmp((header+2+Ustrlen(context->boundary)), "--", 2) == 0)
- {
- /* END boundary found */
- debug_printf("End boundary found %s\n", context->boundary);
- return rc;
- }
- else
- debug_printf("Next part with boundary %s\n", context->boundary);
+ /* Hit EOF or read error. Ugh. */
+ DEBUG(D_acl) debug_printf_indent("MIME: Hit EOF ...\n");
+ return rc;
+ }
- /* can't use break here */
- goto DECODE_HEADERS;
+ /* boundary line must start with 2 dashes */
+ if ( Ustrncmp(header, "--", 2) == 0
+ && Ustrncmp(header+2, context->boundary, Ustrlen(context->boundary)) == 0
+ )
+ { /* found boundary */
+ if (Ustrncmp((header+2+Ustrlen(context->boundary)), "--", 2) == 0)
+ {
+ /* END boundary found */
+ DEBUG(D_acl) debug_printf_indent("MIME: End boundary found %s\n",
+ context->boundary);
+ return rc;
}
+
+ DEBUG(D_acl) debug_printf_indent("MIME: Next part with boundary %s\n",
+ context->boundary);
+ break;
}
- /* Hit EOF or read error. Ugh. */
- debug_printf("Hit EOF ...\n");
- return rc;
}
-DECODE_HEADERS:
/* parse headers, set up expansion variables */
while (mime_get_header(f, header))
{
- int i;
- /* loop through header list */
- for (i = 0; i < mime_header_list_size; i++)
- if (strncmpic(mime_header_list[i].name,
- header, mime_header_list[i].namelen) == 0)
- { /* found an interesting header */
- uschar * header_value;
- int header_value_len;
- uschar * p = header + mime_header_list[i].namelen;
-
- /* grab the value (normalize to lower case)
- and copy to its corresponding expansion variable */
- while(*p != ';')
- {
- *p = tolower(*p);
- p++;
- }
- header_value_len = p - (header + mime_header_list[i].namelen);
- p = header + mime_header_list[i].namelen;
- header_value = string_copyn(p, header_value_len);
- debug_printf("Found %s MIME header, value is '%s'\n",
- mime_header_list[i].name, header_value);
- *((uschar **)(mime_header_list[i].value)) = header_value;
+ struct mime_header * mh;
+
+ /* look for interesting headers */
+ for (mh = mime_header_list;
+ mh < mime_header_list + mime_header_list_size;
+ mh++) if (strncmpic(mh->name, header, mh->namelen) == 0)
+ {
+ uschar * p = header + mh->namelen;
+ uschar * q;
- /* make p point to the next character after the closing ';' */
- p += header_value_len+1;
+ /* grab the value (normalize to lower case)
+ and copy to its corresponding expansion variable */
+
+ for (q = p; *q != ';' && *q; q++) ;
+ *mh->value = string_copynlc(p, q-p);
+ DEBUG(D_acl) debug_printf_indent("MIME: found %s header, value is '%s'\n",
+ mh->name, *mh->value);
+
+ if (*(p = q)) p++; /* jump past the ; */
+
+ {
+ uschar * mime_fname = NULL;
+ uschar * mime_fname_rfc2231 = NULL;
+ uschar * mime_filename_charset = NULL;
+ BOOL decoding_failed = FALSE;
/* grab all param=value tags on the remaining line,
check if they are interesting */
-NEXT_PARAM_SEARCH:
+
while (*p)
{
- /* debug_printf(" considering paramlist '%s'\n", p); */
mime_parameter * mp;
- for (mp = mime_parameter_list;
- mp < &mime_parameter_list[mime_parameter_list_size];
- mp++)
- {
- uschar * param_value = NULL;
-
- /* found an interesting parameter? */
- if (strncmpic(mp->name, p, mp->namelen) == 0)
+
+ DEBUG(D_acl) debug_printf_indent("MIME: considering paramlist '%s'\n", p);
+
+ if ( !mime_filename
+ && strncmpic(CUS"content-disposition:", header, 20) == 0
+ && strncmpic(CUS"filename*", p, 9) == 0
+ )
+ { /* RFC 2231 filename */
+ uschar * q;
+
+ /* find value of the filename */
+ p += 9;
+ while(*p != '=' && *p) p++;
+ if (*p) p++; /* p is filename or NUL */
+ q = mime_param_val(&p); /* p now trailing ; or NUL */
+
+ if (q && *q)
{
- int size = 0;
- int ptr = 0;
+ uschar * temp_string, * err_msg;
+ int slen;
- /* yes, grab the value and copy to its corresponding expansion variable */
- p += mp->namelen;
- while(*p && *p != ';') /* ; terminates */
- if (*p == '"')
+ /* build up an un-decoded filename over successive
+ filename*= parameters (for use when 2047 decode fails) */
+
+ mime_fname_rfc2231 = string_sprintf("%#s%s",
+ mime_fname_rfc2231, q);
+
+ if (!decoding_failed)
+ {
+ int size;
+ if (!mime_filename_charset)
{
- p++; /* skip leading " */
- while(*p && *p != '"') /* " protects ; */
- param_value = string_cat(param_value, &size, &ptr, p++, 1);
- if (*p) p++; /* skip trailing " */
+ uschar * s = q;
+
+ /* look for a ' in the "filename" */
+ while(*s != '\'' && *s) s++; /* s is 1st ' or NUL */
+
+ if ((size = s-q) > 0)
+ mime_filename_charset = string_copyn(q, size);
+
+ if (*(p = s)) p++;
+ while(*p == '\'') p++; /* p is after 2nd ' */
}
else
- param_value = string_cat(param_value, &size, &ptr, p++, 1);
- if (*p) p++; /* skip trailing ; */
+ p = q;
- if (param_value)
- {
- uschar * dummy;
- param_value[ptr++] = '\0';
-
- param_value = rfc2047_decode(param_value,
- check_rfc2047_length, NULL, 32, NULL, &dummy);
- debug_printf(" Found %s MIME parameter in %s header, "
- "value is '%s'\n", mp->name, mime_header_list[i].name,
- param_value);
+ DEBUG(D_acl) debug_printf_indent("MIME: charset %s fname '%s'\n",
+ mime_filename_charset ? mime_filename_charset : US"<NULL>", p);
+
+ temp_string = rfc2231_to_2047(p, mime_filename_charset, &slen);
+ DEBUG(D_acl) debug_printf_indent("MIME: 2047-name %s\n", temp_string);
+
+ temp_string = rfc2047_decode(temp_string, FALSE, NULL, ' ',
+ NULL, &err_msg);
+ DEBUG(D_acl) debug_printf_indent("MIME: plain-name %s\n", temp_string);
+
+ if (!temp_string || (size = Ustrlen(temp_string)) == slen)
+ decoding_failed = TRUE;
+ else
+ /* build up a decoded filename over successive
+ filename*= parameters */
+
+ mime_filename = mime_fname = mime_fname
+ ? string_sprintf("%s%s", mime_fname, temp_string)
+ : temp_string;
}
- *mp->value = param_value;
- goto NEXT_PARAM_SEARCH;
- }
- }
- /* There is something, but not one of our interesting parameters.
- Advance to the next unquoted semicolon */
- while(*p && *p != ';')
- if (*p == '"')
- {
- while(*++p && *p != '"') ;
- if (*p) p++;
+ }
}
+
else
- p++;
- if (*p) p++;
+ /* look for interesting parameters */
+ for (mp = mime_parameter_list;
+ mp < mime_parameter_list + nelem(mime_parameter_list);
+ mp++
+ ) if (strncmpic(mp->name, p, mp->namelen) == 0)
+ {
+ uschar * q;
+ uschar * dummy_errstr;
+
+ /* grab the value and copy to its expansion variable */
+ p += mp->namelen;
+ q = mime_param_val(&p); /* p now trailing ; or NUL */
+
+ *mp->value = q && *q
+ ? rfc2047_decode(q, check_rfc2047_length, NULL, 32, NULL,
+ &dummy_errstr)
+ : NULL;
+ DEBUG(D_acl) debug_printf_indent(
+ "MIME: found %s parameter in %s header, value '%s'\n",
+ mp->name, mh->name, *mp->value);
+
+ break; /* done matching param names */
+ }
+
+
+ /* There is something, but not one of our interesting parameters.
+ Advance past the next semicolon */
+ p = mime_next_semicolon(p);
+ if (*p) p++;
+ } /* param scan on line */
+
+ if (strncmpic(CUS"content-disposition:", header, 20) == 0)
+ {
+ if (decoding_failed) mime_filename = mime_fname_rfc2231;
+
+ DEBUG(D_acl) debug_printf_indent(
+ "MIME: found %s parameter in %s header, value is '%s'\n",
+ "filename", mh->name, mime_filename);
+ }
}
}
- }
+ }
/* set additional flag variables (easier access) */
- if ( (mime_content_type != NULL) &&
- (Ustrncmp(mime_content_type,"multipart",9) == 0) )
+ if ( mime_content_type
+ && Ustrncmp(mime_content_type,"multipart",9) == 0
+ )
mime_is_multipart = 1;
/* Make a copy of the boundary pointer.
(nested_context.boundary != NULL) &&
(Ustrncmp(mime_content_type,"multipart",9) == 0) )
{
- debug_printf("Entering multipart recursion, boundary '%s'\n", nested_context.boundary);
+ DEBUG(D_acl)
+ debug_printf_indent("MIME: Entering multipart recursion, boundary '%s'\n",
+ nested_context.boundary);
nested_context.context =
context && context->context == MBC_ATTACHMENT
if (!mime_decoded_filename) /* decoding failed */
{
log_write(0, LOG_MAIN,
- "mime_regex acl condition warning - could not decode RFC822 MIME part to file.");
- return DEFER;
+ "MIME acl condition warning - could not decode RFC822 MIME part to file.");
+ rc = DEFER;
+ goto out;
}
mime_decoded_filename = NULL;
}
NO_RFC822:
/* If the boundary of this instance is NULL, we are finished here */
- if (context == NULL) break;
+ if (!context) break;
if (context->context == MBC_COVERLETTER_ONESHOT)
context->context = MBC_ATTACHMENT;
}
+out:
+mime_vars_reset();
return rc;
}
git://git.exim.org / exim.git / blobdiff