X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/8e669ac162fe3b1040297f1d021de10778dce9d9..baee9eee9aebe1af195d4f11a77277851c9fe098:/src/src/mime.c diff --git a/src/src/mime.c b/src/src/mime.c index 0a6367200..ca560d447 100644 --- a/src/src/mime.c +++ b/src/src/mime.c @@ -1,4 +1,4 @@ -/* $Cambridge: exim/src/src/mime.c,v 1.4 2005/02/17 11:58:26 ph10 Exp $ */ +/* $Cambridge: exim/src/src/mime.c,v 1.16 2009/11/06 13:29:47 nm4 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -41,201 +41,189 @@ void mime_set_anomaly(int level, char *text) { 0-255 - char to write */ -unsigned int mime_qp_hstr_i(uschar *cptr) { - unsigned int i, j = 0; - while (cptr && *cptr && isxdigit(*cptr)) { - i = *cptr++ - '0'; - if (9 < i) i -= 7; - j <<= 4; - j |= (i & 0x0f); - } - return(j); -} - -uschar *mime_decode_qp_char(uschar *qp_p,int *c) { - uschar hex[] = {0,0,0}; - int nan = 0; +uschar *mime_decode_qp_char(uschar *qp_p, int *c) { uschar *initial_pos = qp_p; /* advance one char */ qp_p++; - REPEAT_FIRST: - if ( (*qp_p == '\t') || (*qp_p == ' ') || (*qp_p == '\r') ) { - /* tab or whitespace may follow - just ignore it, but remember - that this is not a valid hex - encoding any more */ - nan = 1; + /* 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++; - goto REPEAT_FIRST; - } - else if ( (('0' <= *qp_p) && (*qp_p <= '9')) || (('A' <= *qp_p) && (*qp_p <= 'F')) || (('a' <= *qp_p) && (*qp_p <= 'f')) ) { - /* this is a valid hex char, if nan is unset */ - if (nan) { - /* this is illegal */ - *c = -2; - return initial_pos; - } - else { - hex[0] = *qp_p; - qp_p++; - }; - } - else if (*qp_p == '\n') { - /* hit soft line break already, continue */ + + if (*qp_p == '\n') { + /* hit soft line break */ *c = -1; return qp_p; - } - else { - /* illegal char here */ - *c = -2; - return initial_pos; }; - if ( (('0' <= *qp_p) && (*qp_p <= '9')) || (('A' <= *qp_p) && (*qp_p <= 'F')) || (('a' <= *qp_p) && (*qp_p <= 'f')) ) { - if (hex[0] > 0) { - hex[1] = *qp_p; - /* do hex conversion */ - *c = mime_qp_hstr_i(hex); - qp_p++; - return qp_p; - } - else { - /* huh ? */ - *c = -2; - return initial_pos; - }; - } - else { - /* illegal char */ - *c = -2; - return initial_pos; - }; + /* illegal char here */ + *c = -2; + return initial_pos; } -uschar *mime_parse_line(uschar *buffer, uschar *encoding, int *num_decoded) { - uschar *data = NULL; - - data = (uschar *)malloc(Ustrlen(buffer)+2); - - if (encoding == NULL) { - /* no encoding type at all */ - NO_DECODING: - memcpy(data, buffer, Ustrlen(buffer)); - data[(Ustrlen(buffer))] = 0; - *num_decoded = Ustrlen(data); - return data; - } - else if (Ustrcmp(encoding,"base64") == 0) { - uschar *p = buffer; - int offset = 0; - - /* ----- BASE64 ---------------------------------------------------- */ - /* NULL out '\r' and '\n' chars */ - while (Ustrrchr(p,'\r') != NULL) { - *(Ustrrchr(p,'\r')) = '\0'; - }; - while (Ustrrchr(p,'\n') != NULL) { - *(Ustrrchr(p,'\n')) = '\0'; - }; +/* just dump MIME part without any decoding */ +static int mime_decode_asis(FILE* in, FILE* out, uschar* boundary) +{ + int len, size = 0; + uschar buffer[MIME_MAX_LINE_LENGTH]; - while (*(p+offset) != '\0') { - /* hit illegal char ? */ - if (mime_b64[*(p+offset)] == 128) { - mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64); - offset++; - } - else { - *p = mime_b64[*(p+offset)]; - p++; - }; - }; - *p = 255; + 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 + ) + break; + + len = Ustrlen(buffer); + if (fwrite(buffer, 1, (size_t)len, out) < len) + return -1; + size += len; + } /* while */ + return size; +} - /* line is translated, start bit shifting */ - p = buffer; - *num_decoded = 0; - while(*p != 255) { - uschar tmp_c; - /* byte 0 ---------------------- */ - if (*(p+1) == 255) { - mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64); - break; - } - data[(*num_decoded)] = *p; - data[(*num_decoded)] <<= 2; - tmp_c = *(p+1); - tmp_c >>= 4; - data[(*num_decoded)] |= tmp_c; - (*num_decoded)++; - p++; - /* byte 1 ---------------------- */ - if (*(p+1) == 255) { - mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64); - break; +/* 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; } - data[(*num_decoded)] = *p; - data[(*num_decoded)] <<= 4; - tmp_c = *(p+1); - tmp_c >>= 2; - data[(*num_decoded)] |= tmp_c; - (*num_decoded)++; - p++; - /* byte 2 ---------------------- */ - if (*(p+1) == 255) { + /* skip bad characters */ + if (mime_b64[*ipos] == 128) { mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64); - break; + continue; } - data[(*num_decoded)] = *p; - data[(*num_decoded)] <<= 6; - data[(*num_decoded)] |= *(p+1); - (*num_decoded)++; - p+=2; + /* 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 */ - }; - return data; - /* ----------------------------------------------------------------- */ + /* write out last byte if it was incomplete */ + if (bytestate & 3) { + if (fwrite(obuf, 1, 1, out) != 1) + return -1; + ++size; } - else if (Ustrcmp(encoding,"quoted-printable") == 0) { - uschar *p = buffer; - /* ----- QP -------------------------------------------------------- */ - *num_decoded = 0; - while (*p != 0) { - if (*p == '=') { + return size; +} + + +/* decode quoted-printable MIME part */ +static int 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; + + 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; - p = mime_decode_qp_char(p,&decode_qp_result); + ipos = mime_decode_qp_char(ipos, &decode_qp_result); if (decode_qp_result == -2) { - /* Error from decoder. p is unchanged. */ + /* Error from decoder. ipos is unchanged. */ mime_set_anomaly(MIME_ANOMALY_BROKEN_QP); - data[(*num_decoded)] = '='; - (*num_decoded)++; - p++; + *opos = '='; + ++opos; + ++ipos; } else if (decode_qp_result == -1) { break; } else if (decode_qp_result >= 0) { - data[(*num_decoded)] = decode_qp_result; - (*num_decoded)++; - }; + *opos = decode_qp_result; + ++opos; + } } else { - data[(*num_decoded)] = *p; - (*num_decoded)++; - p++; - }; - }; - return data; - /* ----------------------------------------------------------------- */ + *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; + } } - /* unknown encoding type, just dump as-is */ - else goto NO_DECODING; + return size; } @@ -246,11 +234,11 @@ FILE *mime_get_decode_file(uschar *pname, uschar *fname) { filename = (uschar *)malloc(2048); if ((pname != NULL) && (fname != NULL)) { - snprintf(CS filename, 2048, "%s/%s", pname, fname); - f = fopen(CS filename,"w+"); + (void)string_format(filename, 2048, "%s/%s", pname, fname); + f = modefopen(filename,"wb+",SPOOL_MODE); } else if (pname == NULL) { - f = fopen(CS fname,"w+"); + f = modefopen(fname,"wb+",SPOOL_MODE); } else if (fname == NULL) { int file_nr = 0; @@ -259,7 +247,7 @@ FILE *mime_get_decode_file(uschar *pname, uschar *fname) { /* must find first free sequential filename */ do { struct stat mystat; - snprintf(CS filename,2048,"%s/%s-%05u", pname, message_id, file_nr); + (void)string_format(filename,2048,"%s/%s-%05u", pname, message_id, file_nr); file_nr++; /* security break */ if (file_nr >= 1024) @@ -267,7 +255,7 @@ FILE *mime_get_decode_file(uschar *pname, uschar *fname) { result = stat(CS filename,&mystat); } while(result != -1); - f = fopen(CS filename,"w+"); + f = modefopen(filename,"wb+",SPOOL_MODE); }; /* set expansion variable */ @@ -284,9 +272,9 @@ int mime_decode(uschar **listptr) { uschar option_buffer[1024]; uschar decode_path[1024]; FILE *decode_file = NULL; - uschar *buffer = NULL; long f_pos = 0; unsigned int size_counter = 0; + int (*decode_function)(FILE*, FILE*, uschar*); if (mime_stream == NULL) return FAIL; @@ -294,15 +282,7 @@ int mime_decode(uschar **listptr) { f_pos = ftell(mime_stream); /* build default decode path (will exist since MBOX must be spooled up) */ - snprintf(CS decode_path,1024,"%s/scan/%s",spool_directory,message_id); - - /* reserve a line buffer to work in */ - buffer = (uschar *)malloc(MIME_MAX_LINE_LENGTH+1); - if (buffer == NULL) { - log_write(0, LOG_PANIC, - "decode ACL condition: can't allocate %d bytes of memory.", MIME_MAX_LINE_LENGTH+1); - return DEFER; - }; + (void)string_format(decode_path,1024,"%s/scan/%s",spool_directory,message_id); /* try to find 1st option */ if ((option = string_nextinlist(&list, &sep, @@ -344,50 +324,28 @@ int mime_decode(uschar **listptr) { if (decode_file == NULL) return DEFER; - /* read data linewise and dump it to the file, - while looking for the current boundary */ - while(fgets(CS buffer, MIME_MAX_LINE_LENGTH, mime_stream) != NULL) { - uschar *decoded_line = NULL; - int decoded_line_length = 0; - - if (mime_current_boundary != NULL) { - /* boundary line must start with 2 dashes */ - if (Ustrncmp(buffer,"--",2) == 0) { - if (Ustrncmp((buffer+2),mime_current_boundary,Ustrlen(mime_current_boundary)) == 0) - break; - }; - }; - - decoded_line = mime_parse_line(buffer, mime_content_transfer_encoding, &decoded_line_length); - /* write line to decode file */ - if (fwrite(decoded_line, 1, decoded_line_length, decode_file) < decoded_line_length) { - /* error/short write */ - clearerr(mime_stream); - fseek(mime_stream,f_pos,SEEK_SET); - return DEFER; - }; - size_counter += decoded_line_length; - - if (size_counter > 1023) { - if ((mime_content_size + (size_counter / 1024)) < 65535) - mime_content_size += (size_counter / 1024); - else - mime_content_size = 65535; - size_counter = (size_counter % 1024); - }; - - free(decoded_line); - } + /* 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; + else + /* unknown encoding type, just dump as-is */ + decode_function = mime_decode_asis; - fclose(decode_file); + size_counter = decode_function(mime_stream, decode_file, mime_current_boundary); clearerr(mime_stream); - fseek(mime_stream,f_pos,SEEK_SET); + fseek(mime_stream, f_pos, SEEK_SET); - /* round up remaining size bytes to one k */ - if (size_counter) { - mime_content_size++; - }; + if (size_counter < 0 || fclose(decode_file) != 0) + return DEFER; + + /* round up to the next KiB */ + mime_content_size = (size_counter + 1023) / 1024; return OK; } @@ -413,7 +371,7 @@ int mime_get_header(FILE *f, uschar *header) { c = fgetc(f); if (c == EOF) break; if ( (c == '\t') || (c == ' ') ) continue; - ungetc(c,f); + (void)ungetc(c,f); }; /* end of the header, terminate with ';' */ c = ';'; @@ -482,7 +440,7 @@ int mime_get_header(FILE *f, uschar *header) { }; }; - if (header[num_copied-1] != ';') { + if ((num_copied > 0) && (header[num_copied-1] != ';')) { header[num_copied-1] = ';'; }; @@ -497,8 +455,8 @@ int mime_get_header(FILE *f, uschar *header) { } -int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar - **user_msgptr, uschar **log_msgptr) { +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; @@ -507,7 +465,7 @@ int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar header = (uschar *)malloc(MIME_MAX_HEADER_SIZE+1); if (header == NULL) { log_write(0, LOG_PANIC, - "acl_smtp_mime: can't allocate %d bytes of memory.", MIME_MAX_HEADER_SIZE+1); + "MIME ACL: can't allocate %d bytes of memory.", MIME_MAX_HEADER_SIZE+1); return DEFER; }; @@ -617,7 +575,7 @@ int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar 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, TRUE, NULL, 32, ¶m_value_len, &q); + 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); @@ -654,7 +612,7 @@ int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar mime_is_coverletter = !(context && context->context == MBC_ATTACHMENT); /* call ACL handling function */ - rc = acl_check(ACL_WHERE_MIME, NULL, acl_smtp_mime, user_msgptr, log_msgptr); + rc = acl_check(ACL_WHERE_MIME, NULL, acl, user_msgptr, log_msgptr); mime_stream = NULL; mime_current_boundary = NULL; @@ -675,7 +633,7 @@ int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar else nested_context.context = MBC_COVERLETTER_ONESHOT; - rc = mime_acl_check(f, &nested_context, user_msgptr, log_msgptr); + rc = mime_acl_check(acl, f, &nested_context, user_msgptr, log_msgptr); if (rc != OK) break; } else if ( (mime_content_type != NULL) && @@ -688,7 +646,7 @@ int mime_acl_check(FILE *f, struct mime_boundary_context *context, uschar /* must find first free sequential filename */ do { struct stat mystat; - snprintf(CS filename,2048,"%s/scan/%s/__rfc822_%05u", spool_directory, message_id, file_nr); + (void)string_format(filename,2048,"%s/scan/%s/__rfc822_%05u", spool_directory, message_id, file_nr); file_nr++; /* security break */ if (file_nr >= 128)