X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/61da15931508341839664aebabe7167dec351c16..8de9db65575ccd8013753bb3d23426f0da2a669a:/src/src/mime.c diff --git a/src/src/mime.c b/src/src/mime.c index cc8a337ae..821cb541d 100644 --- a/src/src/mime.c +++ b/src/src/mime.c @@ -1,31 +1,57 @@ -/* $Cambridge: exim/src/src/mime.c,v 1.17 2009/11/07 17:17:15 nm4 Exp $ */ - /************************************************* * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) Tom Kistner 2004 */ -/* License: GPL */ +/* Copyright (c) Tom Kistner 2004, 2015 + * License: GPL + * Copyright (c) The Exim Maintainers 2016 + */ #include "exim.h" -#ifdef WITH_CONTENT_SCAN +#ifdef WITH_CONTENT_SCAN /* entire file */ #include "mime.h" #include FILE *mime_stream = NULL; uschar *mime_current_boundary = NULL; +static mime_header mime_header_list[] = { + { 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[] = { + { 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, char *text) { - mime_anomaly_level = level; - mime_anomaly_text = US text; +void +mime_set_anomaly(int idx) +{ +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; } @@ -41,648 +67,759 @@ void mime_set_anomaly(int level, char *text) { 0-255 - char to write */ -uschar *mime_decode_qp_char(uschar *qp_p, int *c) { - uschar *initial_pos = qp_p; +static uschar * +mime_decode_qp_char(uschar *qp_p, int *c) +{ +uschar *initial_pos = qp_p; + +/* advance one char */ +qp_p++; + +/* Check for two hex digits and decode them */ +if (isxdigit(*qp_p) && isxdigit(qp_p[1])) + { + /* Do hex conversion */ + *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) <<4; + qp_p++; + *c |= isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10; + return qp_p + 1; + } - /* advance one char */ +/* tab or whitespace may follow just ignore it if it precedes \n */ +while (*qp_p == '\t' || *qp_p == ' ' || *qp_p == '\r') qp_p++; - /* Check for two hex digits and decode them */ - if (isxdigit(*qp_p) && isxdigit(qp_p[1])) { - /* Do hex conversion */ - if (isdigit(*qp_p)) {*c = *qp_p - '0';} - else {*c = toupper(*qp_p) - 'A' + 10;}; - *c <<= 4; - if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';} - else {*c |= toupper(qp_p[1]) - 'A' + 10;}; - return qp_p + 2; - }; - - /* tab or whitespace may follow just ignore it if it precedes \n */ - while (*qp_p == '\t' || *qp_p == ' ' || *qp_p == '\r') - qp_p++; - - if (*qp_p == '\n') { - /* hit soft line break */ - *c = -1; - return qp_p; - }; - - /* illegal char here */ - *c = -2; - return initial_pos; +if (*qp_p == '\n') /* hit soft line break */ + { + *c = -1; + return qp_p; + } + +/* illegal char here */ +*c = -2; +return initial_pos; } /* just dump MIME part without any decoding */ -static int mime_decode_asis(FILE* in, FILE* out, uschar* boundary) +static ssize_t +mime_decode_asis(FILE* in, FILE* out, uschar* boundary) { - int len, size = 0; + ssize_t len, size = 0; uschar buffer[MIME_MAX_LINE_LENGTH]; - while(fgets(CS buffer, MIME_MAX_LINE_LENGTH, mime_stream) != NULL) { + while(fgets(CS buffer, MIME_MAX_LINE_LENGTH, mime_stream) != NULL) + { if (boundary != NULL - && Ustrncmp(buffer, "--", 2) == 0 - && Ustrncmp((buffer+2), boundary, Ustrlen(boundary)) == 0 - ) + && Ustrncmp(buffer, "--", 2) == 0 + && Ustrncmp((buffer+2), boundary, Ustrlen(boundary)) == 0 + ) break; len = Ustrlen(buffer); if (fwrite(buffer, 1, (size_t)len, out) < len) return -1; size += len; - } /* while */ + } /* while */ return size; } -/* decode base64 MIME part */ -static int mime_decode_base64(FILE* in, FILE* out, uschar* boundary) -{ - uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH]; - uschar *ipos, *opos; - size_t len, size = 0; - int bytestate = 0; - - opos = obuf; - - while (fgets(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) { - /* skip padding */ - if (*ipos == '=') { - ++bytestate; - continue; - } - /* skip bad characters */ - if (mime_b64[*ipos] == 128) { - 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 int mime_decode_qp(FILE* in, FILE* out, uschar* boundary) +static ssize_t +mime_decode_qp(FILE* in, FILE* out, uschar* boundary) { - uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH]; - uschar *ipos, *opos; - size_t len, size = 0; +uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH]; +uschar *ipos, *opos; +ssize_t len, size = 0; - while (fgets(CS ibuf, MIME_MAX_LINE_LENGTH, in) != NULL) +while (fgets(CS ibuf, MIME_MAX_LINE_LENGTH, in) != NULL) { - if (boundary != NULL - && Ustrncmp(ibuf, "--", 2) == 0 - && Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0 - ) - break; /* todo: check for missing boundary */ - - ipos = ibuf; - opos = obuf; - - while (*ipos != 0) { - if (*ipos == '=') { - int decode_qp_result; - - ipos = mime_decode_qp_char(ipos, &decode_qp_result); - - if (decode_qp_result == -2) { - /* Error from decoder. ipos is unchanged. */ - mime_set_anomaly(MIME_ANOMALY_BROKEN_QP); - *opos = '='; - ++opos; - ++ipos; - } - else if (decode_qp_result == -1) { - break; - } - else if (decode_qp_result >= 0) { - *opos = decode_qp_result; - ++opos; - } + if (boundary != NULL + && Ustrncmp(ibuf, "--", 2) == 0 + && Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0 + ) + break; /* todo: check for missing boundary */ + + ipos = ibuf; + opos = obuf; + + while (*ipos != 0) + { + if (*ipos == '=') + { + int decode_qp_result; + + ipos = mime_decode_qp_char(ipos, &decode_qp_result); + + if (decode_qp_result == -2) + { + /* Error from decoder. ipos is unchanged. */ + mime_set_anomaly(MIME_ANOMALY_BROKEN_QP); + *opos = '='; + ++opos; + ++ipos; + } + else if (decode_qp_result == -1) + break; + else if (decode_qp_result >= 0) + { + *opos = decode_qp_result; + ++opos; + } } - else { - *opos = *ipos; - ++opos; - ++ipos; + else + { + *opos = *ipos; + ++opos; + ++ipos; } } - /* something to write? */ - len = opos - obuf; - if (len > 0) { - if (fwrite(obuf, 1, len, out) != len) - return -1; /* error */ - size += len; + /* something to write? */ + len = opos - obuf; + if (len > 0) + { + if (fwrite(obuf, 1, len, out) != len) return -1; /* error */ + size += len; } } - return size; +return size; } -FILE *mime_get_decode_file(uschar *pname, uschar *fname) { - FILE *f = NULL; - uschar *filename; - - filename = (uschar *)malloc(2048); - - if ((pname != NULL) && (fname != NULL)) { - (void)string_format(filename, 2048, "%s/%s", pname, fname); - f = modefopen(filename,"wb+",SPOOL_MODE); - } - else if (pname == NULL) { - f = modefopen(fname,"wb+",SPOOL_MODE); +/* + * 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) +{ +if (pname && fname) + mime_decoded_filename = string_sprintf("%s/%s", pname, fname); +else if (!pname) + mime_decoded_filename = string_copy(fname); +else if (!fname) + { + int file_nr = 0; + int result = 0; + + /* must find first free sequential filename */ + do + { + struct stat mystat; + mime_decoded_filename = string_sprintf("%s/%s-%05u", pname, message_id, file_nr++); + /* security break */ + if (file_nr >= 1024) + break; + result = stat(CS mime_decoded_filename, &mystat); + } while(result != -1); } - else if (fname == NULL) { - int file_nr = 0; - int result = 0; - - /* must find first free sequential filename */ - do { - struct stat mystat; - (void)string_format(filename,2048,"%s/%s-%05u", pname, message_id, file_nr); - file_nr++; - /* security break */ - if (file_nr >= 1024) - break; - result = stat(CS 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 mime_decode(uschar **listptr) { - int sep = 0; - uschar *list = *listptr; - uschar *option; - uschar option_buffer[1024]; - uschar decode_path[1024]; - FILE *decode_file = NULL; - long f_pos = 0; - unsigned int size_counter = 0; - int (*decode_function)(FILE*, FILE*, uschar*); - - if (mime_stream == NULL) +int +mime_decode(const uschar **listptr) +{ +int sep = 0; +const uschar *list = *listptr; +uschar *option; +uschar option_buffer[1024]; +uschar decode_path[1024]; +FILE *decode_file = NULL; +long f_pos = 0; +ssize_t size_counter = 0; +ssize_t (*decode_function)(FILE*, FILE*, uschar*); + +if (!mime_stream || (f_pos = ftell(mime_stream)) < 0) + return FAIL; + +/* 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); + +/* try to find 1st option */ +if ((option = string_nextinlist(&list, &sep, + option_buffer, + sizeof(option_buffer))) != NULL) + { + /* parse 1st option */ + if ((Ustrcmp(option,"false") == 0) || (Ustrcmp(option,"0") == 0)) + /* explicitly no decoding */ 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); - - /* try to find 1st option */ - if ((option = string_nextinlist(&list, &sep, - option_buffer, - sizeof(option_buffer))) != NULL) { - - /* parse 1st option */ - if ( (Ustrcmp(option,"false") == 0) || (Ustrcmp(option,"0") == 0) ) { - /* explicitly no decoding */ - return FAIL; - }; - - if (Ustrcmp(option,"default") == 0) { - /* explicit default path + file names */ - goto DEFAULT_PATH; - }; + if (Ustrcmp(option,"default") == 0) + /* explicit default path + file names */ + goto DEFAULT_PATH; - if (option[0] == '/') { - struct stat statbuf; + if (option[0] == '/') + { + struct stat statbuf; - memset(&statbuf,0,sizeof(statbuf)); + memset(&statbuf,0,sizeof(statbuf)); - /* assume either path or path+file name */ - if ( (stat(CS option, &statbuf) == 0) && S_ISDIR(statbuf.st_mode) ) - /* is directory, use it as decode_path */ - decode_file = mime_get_decode_file(option, NULL); - else - /* does not exist or is a file, use as full file name */ - decode_file = mime_get_decode_file(NULL, option); - } + /* assume either path or path+file name */ + if ( (stat(CS option, &statbuf) == 0) && S_ISDIR(statbuf.st_mode) ) + /* is directory, use it as decode_path */ + decode_file = mime_get_decode_file(option, NULL); else - /* assume file name only, use default path */ - decode_file = mime_get_decode_file(decode_path, option); - } - else - /* no option? patch default path */ - DEFAULT_PATH: decode_file = mime_get_decode_file(decode_path, NULL); - - if (decode_file == NULL) - return DEFER; - - /* decode according to mime type */ - if (mime_content_transfer_encoding == NULL) - /* no encoding, dump as-is */ - decode_function = mime_decode_asis; - else if (Ustrcmp(mime_content_transfer_encoding, "base64") == 0) - decode_function = mime_decode_base64; - else if (Ustrcmp(mime_content_transfer_encoding, "quoted-printable") == 0) - decode_function = mime_decode_qp; + /* does not exist or is a file, use as full file name */ + decode_file = mime_get_decode_file(NULL, option); + } else - /* unknown encoding type, just dump as-is */ - decode_function = mime_decode_asis; + /* assume file name only, use default path */ + decode_file = mime_get_decode_file(decode_path, option); + } +else + { + /* no option? patch default path */ +DEFAULT_PATH: + decode_file = mime_get_decode_file(decode_path, NULL); + } - size_counter = decode_function(mime_stream, decode_file, mime_current_boundary); +if (!decode_file) + return DEFER; - clearerr(mime_stream); - fseek(mime_stream, f_pos, SEEK_SET); +/* decode according to mime type */ +decode_function = + !mime_content_transfer_encoding + ? mime_decode_asis /* no encoding, dump as-is */ + : Ustrcmp(mime_content_transfer_encoding, "base64") == 0 + ? mime_decode_base64 + : Ustrcmp(mime_content_transfer_encoding, "quoted-printable") == 0 + ? mime_decode_qp + : mime_decode_asis; /* unknown encoding type, just dump as-is */ - if (fclose(decode_file) != 0 || size_counter < 0) - return DEFER; +size_counter = decode_function(mime_stream, decode_file, mime_current_boundary); - /* round up to the next KiB */ - mime_content_size = (size_counter + 1023) / 1024; +clearerr(mime_stream); +if (fseek(mime_stream, f_pos, SEEK_SET)) + return DEFER; - return OK; -} +if (fclose(decode_file) != 0 || size_counter < 0) + return DEFER; -int mime_get_header(FILE *f, uschar *header) { - int c = EOF; - int done = 0; - int header_value_mode = 0; - int header_open_brackets = 0; - int num_copied = 0; +/* round up to the next KiB */ +mime_content_size = (size_counter + 1023) / 1024; - while(!done) { +return OK; +} - c = fgetc(f); - if (c == EOF) break; - /* always skip CRs */ - if (c == '\r') continue; +static int +mime_get_header(FILE *f, uschar *header) +{ +int c = EOF; +int done = 0; +int header_value_mode = 0; +int header_open_brackets = 0; +int num_copied = 0; - if (c == '\n') { - if (num_copied > 0) { - /* look if next char is '\t' or ' ' */ - c = fgetc(f); - if (c == EOF) break; - if ( (c == '\t') || (c == ' ') ) continue; - (void)ungetc(c,f); - }; - /* end of the header, terminate with ';' */ - c = ';'; - done = 1; - }; +while(!done) + { + if ((c = fgetc(f)) == EOF) break; + + /* always skip CRs */ + if (c == '\r') continue; + + if (c == '\n') + { + if (num_copied > 0) + { + /* look if next char is '\t' or ' ' */ + if ((c = fgetc(f)) == EOF) break; + if ( (c == '\t') || (c == ' ') ) continue; + (void)ungetc(c,f); + } + /* end of the header, terminate with ';' */ + c = ';'; + done = 1; + } - /* skip control characters */ - if (c < 32) continue; + /* skip control characters */ + if (c < 32) continue; - if (header_value_mode) { - /* --------- value mode ----------- */ - /* skip leading whitespace */ - if ( ((c == '\t') || (c == ' ')) && (header_value_mode == 1) ) - continue; + if (header_value_mode) + { + /* --------- value mode ----------- */ + /* skip leading whitespace */ + if ( ((c == '\t') || (c == ' ')) && (header_value_mode == 1) ) + continue; /* we have hit a non-whitespace char, start copying value data */ header_value_mode = 2; - /* skip quotes */ - if (c == '"') continue; + if (c == '"') /* flip "quoted" mode */ + header_value_mode = header_value_mode==2 ? 3 : 2; - /* leave value mode on ';' */ - if (c == ';') { + /* leave value mode on unquoted ';' */ + if (header_value_mode == 2 && c == ';') { header_value_mode = 0; }; /* -------------------------------- */ } - else { - /* -------- non-value mode -------- */ - /* skip whitespace + tabs */ - if ( (c == ' ') || (c == '\t') ) - continue; - if (c == '\\') { - /* quote next char. can be used - to escape brackets. */ - c = fgetc(f); - if (c == EOF) break; + else + { + /* -------- non-value mode -------- */ + /* skip whitespace + tabs */ + if ( (c == ' ') || (c == '\t') ) + continue; + if (c == '\\') + { + /* quote next char. can be used + to escape brackets. */ + if ((c = fgetc(f)) == EOF) break; } - else if (c == '(') { - header_open_brackets++; - continue; + else if (c == '(') + { + header_open_brackets++; + continue; } - else if ((c == ')') && header_open_brackets) { - header_open_brackets--; - continue; + else if ((c == ')') && header_open_brackets) + { + header_open_brackets--; + continue; } - else if ( (c == '=') && !header_open_brackets ) { - /* enter value mode */ - header_value_mode = 1; - }; + else if ( (c == '=') && !header_open_brackets ) /* enter value mode */ + header_value_mode = 1; - /* skip chars while we are in a comment */ - if (header_open_brackets > 0) - continue; - /* -------------------------------- */ - }; + /* skip chars while we are in a comment */ + if (header_open_brackets > 0) + continue; + /* -------------------------------- */ + } - /* copy the char to the buffer */ - header[num_copied] = (uschar)c; - /* raise counter */ - num_copied++; + /* copy the char to the buffer */ + header[num_copied++] = (uschar)c; - /* break if header buffer is full */ - if (num_copied > MIME_MAX_HEADER_SIZE-1) { - done = 1; - }; - }; + /* break if header buffer is full */ + if (num_copied > MIME_MAX_HEADER_SIZE-1) + done = 1; + } - if ((num_copied > 0) && (header[num_copied-1] != ';')) { - header[num_copied-1] = ';'; - }; +if ((num_copied > 0) && (header[num_copied-1] != ';')) + header[num_copied-1] = ';'; - /* 0-terminate */ - header[num_copied] = '\0'; +/* 0-terminate */ +header[num_copied] = '\0'; - /* return 0 for EOF or empty line */ - if ((c == EOF) || (num_copied == 1)) - return 0; - else - return 1; +/* return 0 for EOF or empty line */ +if ((c == EOF) || (num_copied == 1)) + return 0; +else + return 1; } -int mime_acl_check(uschar *acl, FILE *f, struct mime_boundary_context *context, - uschar **user_msgptr, uschar **log_msgptr) { - int rc = OK; - uschar *header = NULL; - struct mime_boundary_context nested_context; - - /* reserve a line buffer to work in */ - header = (uschar *)malloc(MIME_MAX_HEADER_SIZE+1); - if (header == NULL) { - log_write(0, LOG_PANIC, - "MIME ACL: can't allocate %d bytes of memory.", MIME_MAX_HEADER_SIZE+1); - return DEFER; - }; - - /* Not actually used at the moment, but will be vital to fixing - * some RFC 2046 nonconformance later... */ - nested_context.parent = context; - - /* loop through parts */ - 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. - */ - - /* NOTE -- there's an error here -- RFC2046 specifically says to - * check for outer boundaries. This code doesn't do that, and - * I haven't fixed this. - * - * (I have moved partway towards adding support, however, by adding - * a "parent" field to my new boundary-context structure.) - */ - if (context != NULL) { - while(fgets(CS header, MIME_MAX_HEADER_SIZE, f) != NULL) { - /* boundary line must start with 2 dashes */ - if (Ustrncmp(header,"--",2) == 0) { - if (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); - }; - /* can't use break here */ - goto DECODE_HEADERS; - } - }; - } - /* 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++) { - uschar *header_value = NULL; - int header_value_len = 0; - - /* found an interesting header? */ - if (strncmpic(mime_header_list[i].name,header,mime_header_list[i].namelen) == 0) { - uschar *p = header + mime_header_list[i].namelen; - /* yes, 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)); - header_value = (uschar *)malloc(header_value_len+1); - memset(header_value,0,header_value_len+1); - p = header + mime_header_list[i].namelen; - Ustrncpy(header_value, 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; - - /* make p point to the next character after the closing ';' */ - p += (header_value_len+1); - - /* grab all param=value tags on the remaining line, check if they are interesting */ - NEXT_PARAM_SEARCH: while (*p != 0) { - int j; - for (j = 0; j < mime_parameter_list_size; j++) { - uschar *param_value = NULL; - int param_value_len = 0; - - /* found an interesting parameter? */ - if (strncmpic(mime_parameter_list[j].name,p,mime_parameter_list[j].namelen) == 0) { - uschar *q = p + mime_parameter_list[j].namelen; - /* yes, grab the value and copy to its corresponding expansion variable */ - while(*q != ';') q++; - param_value_len = (q - (p + mime_parameter_list[j].namelen)); - param_value = (uschar *)malloc(param_value_len+1); - memset(param_value,0,param_value_len+1); - q = p + mime_parameter_list[j].namelen; - Ustrncpy(param_value, q, param_value_len); - param_value = rfc2047_decode(param_value, check_rfc2047_length, NULL, 32, ¶m_value_len, &q); - debug_printf("Found %s MIME parameter in %s header, value is '%s'\n", mime_parameter_list[j].name, mime_header_list[i].name, param_value); - *((uschar **)(mime_parameter_list[j].value)) = param_value; - p += (mime_parameter_list[j].namelen + param_value_len + 1); - goto NEXT_PARAM_SEARCH; - }; - } - /* There is something, but not one of our interesting parameters. - Advance to the next semicolon */ - while(*p != ';') p++; - p++; - }; - }; - }; - }; +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; +} - /* set additional flag variables (easier access) */ - if ( (mime_content_type != NULL) && - (Ustrncmp(mime_content_type,"multipart",9) == 0) ) - mime_is_multipart = 1; - /* Make a copy of the boundary pointer. - Required since mime_boundary is global - and can be overwritten further down in recursion */ - nested_context.boundary = mime_boundary; +/* Grab a parameter value, dealing with quoting. - /* raise global counter */ - mime_part_count++; +Arguments: + str Input string. Updated on return to point to terminating ; or NUL - /* copy current file handle to global variable */ - mime_stream = f; - mime_current_boundary = context ? context->boundary : 0; +Return: + Allocated string with parameter value +*/ +static uschar * +mime_param_val(uschar ** sp) +{ +uschar * s = *sp; +uschar * val = NULL; +int size = 0, ptr = 0; + +/* 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, &size, &ptr, s++, 1); + if (*s) s++; /* skip closing " */ + } + else + val = string_catn(val, &size, &ptr, s++, 1); +if (val) val[ptr] = '\0'; +*sp = s; +return val; +} - /* Note the context */ - mime_is_coverletter = !(context && context->context == MBC_ATTACHMENT); +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; +} - /* call ACL handling function */ - rc = acl_check(ACL_WHERE_MIME, NULL, acl, user_msgptr, log_msgptr); - mime_stream = NULL; - mime_current_boundary = NULL; +static uschar * +rfc2231_to_2047(const uschar * fname, const uschar * charset, int * len) +{ +int size = 0, ptr = 0; +uschar * val = string_catn(NULL, &size, &ptr, US"=?", 2); +uschar c; + +if (charset) + val = string_cat(val, &size, &ptr, charset); +val = string_catn(val, &size, &ptr, US"?Q?", 3); + +while ((c = *fname)) + if (c == '%' && isxdigit(fname[1]) && isxdigit(fname[2])) + { + val = string_catn(val, &size, &ptr, US"=", 1); + val = string_catn(val, &size, &ptr, ++fname, 2); + fname += 2; + } + else + val = string_catn(val, &size, &ptr, fname++, 1); - if (rc != OK) break; +val = string_catn(val, &size, &ptr, US"?=", 2); +val[*len = ptr] = '\0'; +return val; +} - /* If we have a multipart entity and a boundary, go recursive */ - if ( (mime_content_type != NULL) && - (nested_context.boundary != NULL) && - (Ustrncmp(mime_content_type,"multipart",9) == 0) ) { - debug_printf("Entering multipart recursion, boundary '%s'\n", nested_context.boundary); - - if (context && context->context == MBC_ATTACHMENT) - nested_context.context = MBC_ATTACHMENT; - else if (!Ustrcmp(mime_content_type,"multipart/alternative") - || !Ustrcmp(mime_content_type,"multipart/related")) - nested_context.context = MBC_COVERLETTER_ALL; - else - nested_context.context = MBC_COVERLETTER_ONESHOT; - - rc = mime_acl_check(acl, f, &nested_context, user_msgptr, log_msgptr); - if (rc != OK) break; + +int +mime_acl_check(uschar *acl, FILE *f, struct mime_boundary_context *context, + uschar **user_msgptr, uschar **log_msgptr) +{ +int rc = OK; +uschar * header = NULL; +struct mime_boundary_context nested_context; + +/* reserve a line buffer to work in */ +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... */ +nested_context.parent = context; + +/* loop through parts */ +while(1) + { + /* reset all per-part mime variables */ + 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 haven't fixed this. + * + * (I have moved partway towards adding support, however, by adding + * a "parent" field to my new boundary-context structure.) + */ + if (context) for (;;) + { + if (!fgets(CS header, MIME_MAX_HEADER_SIZE, f)) + { + /* Hit EOF or read error. Ugh. */ + DEBUG(D_acl) debug_printf_indent("MIME: Hit EOF ...\n"); + return rc; + } + + /* 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; + } } - else if ( (mime_content_type != NULL) && - (Ustrncmp(mime_content_type,"message/rfc822",14) == 0) ) { - uschar *rfc822name = NULL; - uschar filename[2048]; - int file_nr = 0; - int result = 0; - - /* must find first free sequential filename */ - do { - struct stat mystat; - (void)string_format(filename,2048,"%s/scan/%s/__rfc822_%05u", spool_directory, message_id, file_nr); - file_nr++; - /* security break */ - if (file_nr >= 128) - goto NO_RFC822; - result = stat(CS filename,&mystat); + + /* parse headers, set up expansion variables */ + while (mime_get_header(f, header)) + { + 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; + + /* 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 */ + + while (*p) + { + mime_parameter * mp; + + 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) + { + uschar * temp_string, * err_msg; + int slen; + + /* 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) + { + 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 + p = q; + + DEBUG(D_acl) debug_printf_indent("MIME: charset %s fname '%s'\n", + mime_filename_charset ? mime_filename_charset : US"", 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); + + size = Ustrlen(temp_string); + + if (size == 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; + } + } + } + + else + /* 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); + } + } } - while(result != -1); - - rfc822name = filename; - - /* decode RFC822 attachment */ - mime_decoded_filename = NULL; - mime_stream = f; - mime_current_boundary = context ? context->boundary : NULL; - mime_decode(&rfc822name); - mime_stream = NULL; - mime_current_boundary = NULL; - if (mime_decoded_filename == NULL) { - /* decoding failed */ - log_write(0, LOG_MAIN, - "mime_regex acl condition warning - could not decode RFC822 MIME part to file."); - return DEFER; - }; - mime_decoded_filename = NULL; - }; + } + + /* set additional flag variables (easier access) */ + if ( mime_content_type + && Ustrncmp(mime_content_type,"multipart",9) == 0 + ) + mime_is_multipart = 1; + + /* Make a copy of the boundary pointer. + Required since mime_boundary is global + and can be overwritten further down in recursion */ + nested_context.boundary = mime_boundary; + + /* raise global counter */ + mime_part_count++; + + /* copy current file handle to global variable */ + mime_stream = f; + mime_current_boundary = context ? context->boundary : 0; + + /* Note the context */ + mime_is_coverletter = !(context && context->context == MBC_ATTACHMENT); + + /* call ACL handling function */ + rc = acl_check(ACL_WHERE_MIME, NULL, acl, user_msgptr, log_msgptr); + + mime_stream = NULL; + mime_current_boundary = NULL; + + if (rc != OK) break; + + /* If we have a multipart entity and a boundary, go recursive */ + if ( (mime_content_type != NULL) && + (nested_context.boundary != NULL) && + (Ustrncmp(mime_content_type,"multipart",9) == 0) ) + { + DEBUG(D_acl) + debug_printf_indent("MIME: Entering multipart recursion, boundary '%s'\n", + nested_context.boundary); + + nested_context.context = + context && context->context == MBC_ATTACHMENT + ? MBC_ATTACHMENT + : Ustrcmp(mime_content_type,"multipart/alternative") == 0 + || Ustrcmp(mime_content_type,"multipart/related") == 0 + ? MBC_COVERLETTER_ALL + : MBC_COVERLETTER_ONESHOT; + + rc = mime_acl_check(acl, f, &nested_context, user_msgptr, log_msgptr); + if (rc != OK) break; + } + else if ( (mime_content_type != NULL) && + (Ustrncmp(mime_content_type,"message/rfc822",14) == 0) ) + { + const uschar *rfc822name = NULL; + uschar filename[2048]; + int file_nr = 0; + int result = 0; - NO_RFC822: - /* If the boundary of this instance is NULL, we are finished here */ - if (context == NULL) break; + /* must find first free sequential filename */ + do + { + struct stat mystat; + (void)string_format(filename, 2048, + "%s/scan/%s/__rfc822_%05u", spool_directory, message_id, file_nr++); + /* security break */ + if (file_nr >= 128) + goto NO_RFC822; + result = stat(CS filename,&mystat); + } while (result != -1); - if (context->context == MBC_COVERLETTER_ONESHOT) - context->context = MBC_ATTACHMENT; + rfc822name = filename; - }; + /* decode RFC822 attachment */ + mime_decoded_filename = NULL; + mime_stream = f; + mime_current_boundary = context ? context->boundary : NULL; + mime_decode(&rfc822name); + mime_stream = NULL; + mime_current_boundary = NULL; + if (!mime_decoded_filename) /* decoding failed */ + { + log_write(0, LOG_MAIN, + "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) break; - return rc; + if (context->context == MBC_COVERLETTER_ONESHOT) + context->context = MBC_ATTACHMENT; + } + +out: +mime_vars_reset(); +return rc; } -#endif +#endif /*WITH_CONTENT_SCAN*/ + +/* vi: sw ai sw=2 +*/