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-rw-r--r--src/lib-smtp/smtp-parser.c587
1 files changed, 587 insertions, 0 deletions
diff --git a/src/lib-smtp/smtp-parser.c b/src/lib-smtp/smtp-parser.c
new file mode 100644
index 0000000..5672ff0
--- /dev/null
+++ b/src/lib-smtp/smtp-parser.c
@@ -0,0 +1,587 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "net.h"
+#include "str.h"
+#include "strescape.h"
+
+#include "smtp-parser.h"
+
+#include <ctype.h>
+
+/* Character definitions from RFC 5321/5322:
+
+ textstring = 1*(%d09 / %d32-126) ; HT, SP, Printable US-ASCII
+ = 1*(%x09 / %x20-7e)
+ ehlo-param = 1*(%d33-126)
+ = 1*(%x21-7e)
+ ehlo-greet = 1*(%d0-9 / %d11-12 / %d14-127)
+ = 1*(%x00-09 / %x0b-0c / %x0e-7f)
+ qtext = %d32-33 / %d35-91 / %d93-126
+ = %x20-21 / %x23-5B / %x5d-7e
+ quoted-pair = %d92 %d32-126
+ = %x5c %x20-7e
+ atext = ALPHA / DIGIT / ; Printable US-ASCII
+ "!" / "#" / ; characters not including
+ "$" / "%" / ; specials. Used for atoms.
+ "&" / "'" /
+ "*" / "+" /
+ "-" / "/" /
+ "=" / "?" /
+ "^" / "_" /
+ "`" / "{" /
+ "|" / "}" /
+ "~"
+ = %x21 / %x23-27 / %x2a-2b / %x2d / %x2f-39 / %x3d /
+ %d3f / %x41-5a / %x5e-7e /
+ esmtp-value = 1*(%d33-60 / %d62-126)
+ = 1*(%x21-3c / %x3e-7e)
+ dcontent = %d33-90 / ; Printable US-ASCII
+ %d94-126 ; excl. "[", "\", "]"
+ = %x21-5a / %x5e-7e
+ xchar = any ASCII CHAR between "!" (33) and "~" (126) inclusive,
+ except for "+" and "=". [RFC 3461]
+ = %x21-2a / %2c-3c / %x3e-7e
+
+ Bit mappings (FIXME: rearrange):
+
+ (1<<0) => %x21-2a / %2c-3c / %x3e-7e (xtext)
+ (1<<1) => %x21 / %x23-27 / %x2a-2b / %x2d / %x2f-39 / %x3d /
+ %d3f / %x41-5a / %x5e-7e /
+ (1<<2) => %x28-29 / %x2c / %x2e / %x3a-3c / %x3e / %x40
+ (1<<8) => %x00-09 / %x0b-0c / %x0e-20 / %x7f
+ (1<<5) => %x09 / %5b-5d
+ (1<<4) => %x5b / %x5d
+ (1<<3) => %x20
+ (1<<9) => %x22
+ (1<<6) => %x2b
+ (1<<7) => %x3d
+ */
+
+/* xtext */
+const uint16_t smtp_xtext_char_mask = (1<<0);
+/* atext */
+const uint16_t smtp_atext_char_mask = (1<<1);
+/* dcontent */
+const uint16_t smtp_dcontent_char_mask = (1<<1)|(1<<2)|(1<<9);
+/* qtext */
+const uint16_t smtp_qtext_char_mask = (1<<1)|(1<<2)|(1<<3)|(1<<4);
+/* textstring */
+const uint16_t smtp_textstr_char_mask = (1<<1)|(1<<2)|(1<<9)|(1<<3)|(1<<5);
+/* esmtp-value */
+const uint16_t smtp_esmtp_value_char_mask = (1<<0)|(1<<6);
+/* ehlo-param */
+const uint16_t smtp_ehlo_param_char_mask = (1<<0)|(1<<6)|(1<<7);
+/* ehlo-greet */
+const uint16_t smtp_ehlo_greet_char_mask = (1<<0)|(1<<6)|(1<<7)|(1<<8);
+/* quoted-pair */
+const uint16_t smtp_qpair_char_mask = (1<<0)|(1<<3)|(1<<6)|(1<<7);
+
+const uint16_t smtp_char_lookup[256] = {
+ 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, // 00
+ 0x100, 0x120, 0x000, 0x100, 0x100, 0x000, 0x100, 0x100, // 08
+ 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, // 10
+ 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, 0x100, // 18
+ 0x108, 0x003, 0x201, 0x003, 0x003, 0x003, 0x003, 0x003, // 20
+ 0x005, 0x005, 0x003, 0x042, 0x005, 0x003, 0x005, 0x003, // 28
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 30
+ 0x003, 0x003, 0x005, 0x005, 0x005, 0x082, 0x005, 0x003, // 38
+ 0x005, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 40
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 48
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 50
+ 0x003, 0x003, 0x003, 0x031, 0x021, 0x031, 0x003, 0x003, // 58
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 60
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 68
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, // 70
+ 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x003, 0x100, // 78
+
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // 80
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // 88
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // 90
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // 98
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // a0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // a8
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // b0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // b8
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // c0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // c8
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // d0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // d8
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // e0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // e8
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // f0
+ 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, // f8
+};
+
+/*
+ * Parser
+ */
+
+void smtp_parser_init(struct smtp_parser *parser,
+ pool_t pool, const char *data)
+{
+ parser->pool = pool;
+ parser->begin = parser->cur = (const unsigned char *)data;
+ parser->end = parser->begin + strlen(data);
+ parser->error = NULL;
+}
+
+/*
+ * Common syntax
+ */
+
+static int
+smtp_parser_parse_ldh_str(struct smtp_parser *parser,
+ string_t *out)
+{
+ const unsigned char *pbegin = parser->cur, *palnum;
+
+ /* Ldh-str = *( ALPHA / DIGIT / "-" ) Let-dig
+ Let-dig = ALPHA / DIGIT
+ */
+
+ /* Ldh-str */
+ palnum = NULL;
+ while (parser->cur < parser->end) {
+ if (i_isalnum(*parser->cur))
+ palnum = parser->cur;
+ else if (*parser->cur != '-')
+ break;
+ parser->cur++;
+ }
+ if (parser->cur == pbegin || palnum == NULL) {
+ parser->cur = pbegin;
+ return 0;
+ }
+
+ parser->cur = palnum+1;
+ if (out != NULL)
+ str_append_data(out, pbegin, parser->cur - pbegin);
+ return 1;
+}
+
+int smtp_parser_parse_domain(struct smtp_parser *parser,
+ const char **value_r)
+{
+ string_t *value = NULL;
+
+ /* Domain = sub-domain *("." sub-domain)
+ sub-domain = Let-dig [Ldh-str]
+ Let-dig = ALPHA / DIGIT
+ Ldh-str = *( ALPHA / DIGIT / "-" ) Let-dig
+
+ NOTE: A more generic syntax is accepted to be lenient towards
+ systems that don't adhere to the standards. It allows
+ '-' and '_' to occur anywhere in a sub-domain.
+ */
+
+ /* Let-dig (first) (nope) */
+ if (parser->cur >= parser->end ||
+ (!i_isalnum(*parser->cur) && *parser->cur != '-' &&
+ *parser->cur != '_'))
+ return 0;
+
+ if (value_r != NULL)
+ value = t_str_new(256);
+
+ for (;;) {
+ /* Let-dig (nope) */
+ if (parser->cur >= parser->end || *parser->cur == '.') {
+ parser->error = "Empty sub-domain";
+ return -1;
+ }
+ if (!i_isalnum(*parser->cur) && *parser->cur != '-' &&
+ *parser->cur != '_') {
+ parser->error = "Invalid character in domain";
+ return -1;
+ }
+ if (value_r != NULL)
+ str_append_c(value, *parser->cur);
+ parser->cur++;
+
+ /* Ldh-str (nope) */
+ while (parser->cur < parser->end) {
+ if (!i_isalnum(*parser->cur) && *parser->cur != '-' &&
+ *parser->cur != '_')
+ break;
+
+ if (value_r != NULL)
+ str_append_c(value, *parser->cur);
+ parser->cur++;
+ }
+
+ /* *("." sub-domain) */
+ if (parser->cur >= parser->end || *parser->cur != '.')
+ break;
+
+ if (value_r != NULL)
+ str_append_c(value, '.');
+ parser->cur++;
+ }
+
+ if (value_r != NULL)
+ *value_r = str_c(value);
+ return 1;
+}
+
+static int
+smtp_parser_parse_snum(struct smtp_parser *parser, string_t *literal,
+ uint8_t *octet_r)
+{
+ const unsigned char *pbegin = parser->cur;
+ uint8_t octet = 0;
+
+ /* Snum = 1*3DIGIT
+ ; representing a decimal integer
+ ; value in the range 0 through 255
+ */
+
+ if (*parser->cur < '0' || *parser->cur > '9')
+ return 0;
+ do {
+ if (octet >= ((uint8_t)-1 / 10)) {
+ if (octet > (uint8_t)-1 / 10)
+ return -1;
+ if ((uint8_t)(*parser->cur - '0') > ((uint8_t)-1 % 10))
+ return -1;
+ }
+ octet = octet * 10 + (*parser->cur - '0');
+ parser->cur++;
+ } while (*parser->cur >= '0' && *parser->cur <= '9');
+
+ if (literal != NULL)
+ str_append_data(literal, pbegin, parser->cur - pbegin);
+ *octet_r = octet;
+ return 1;
+}
+
+static int
+smtp_parser_parse_ipv4_address(struct smtp_parser *parser,
+ string_t *literal, struct in_addr *ip4_r)
+{
+ uint8_t octet;
+ uint32_t ip = 0;
+ int ret;
+ int i;
+
+ /* IPv4-address-literal = Snum 3("." Snum) */
+ if ((ret = smtp_parser_parse_snum(parser, literal, &octet)) <= 0)
+ return ret;
+ ip = octet;
+
+ for (i = 0; i < 3 && parser->cur < parser->end; i++) {
+ if (*parser->cur != '.')
+ return -1;
+
+ if (literal != NULL)
+ str_append_c(literal, '.');
+ parser->cur++;
+
+ if (smtp_parser_parse_snum(parser, literal, &octet) <= 0)
+ return -1;
+ ip = (ip << 8) + octet;
+ }
+
+ if (ip4_r != NULL)
+ ip4_r->s_addr = htonl(ip);
+ return 1;
+}
+
+int smtp_parser_parse_address_literal(struct smtp_parser *parser,
+ const char **value_r, struct ip_addr *ip_r)
+{
+ const unsigned char *pblock;
+ struct in_addr ip4;
+ struct in6_addr ip6;
+ bool ipv6 = FALSE;
+ string_t *value = NULL, *tagbuf;
+ int ret;
+
+ /* address-literal = "[" ( IPv4-address-literal /
+ IPv6-address-literal /
+ General-address-literal ) "]"
+ ; See Section 4.1.3
+
+ IPv6-address-literal = "IPv6:" IPv6-addr
+ General-address-literal = Standardized-tag ":" 1*dcontent
+ Standardized-tag = Ldh-str
+ ; Standardized-tag MUST be specified in a
+ ; Standards-Track RFC and registered with
+ ; IANA
+ dcontent = %d33-90 / ; Printable US-ASCII
+ %d94-126 ; excl. "[", "\", "]"
+ */
+
+ /* "[" */
+ if (parser->cur >= parser->end || *parser->cur != '[')
+ return 0;
+ parser->cur++;
+
+ if (value_r != NULL) {
+ value = t_str_new(128);
+ str_append_c(value, '[');
+ }
+ if (ip_r != NULL)
+ i_zero(ip_r);
+
+ /* IPv4-address-literal / ... */
+ i_zero(&ip4);
+ if ((ret=smtp_parser_parse_ipv4_address(parser, value, &ip4)) != 0) {
+ if (ret < 0) {
+ parser->error = "Invalid IPv4 address literal";
+ return -1;
+ }
+ if (ip_r != NULL) {
+ ip_r->family = AF_INET;
+ ip_r->u.ip4 = ip4;
+ }
+
+ /* ... / IPv6-address-literal / General-address-literal */
+ } else {
+ /* IPv6-address-literal = "IPv6:" IPv6-addr
+ General-address-literal = Standardized-tag ":" 1*dcontent
+ Standardized-tag = Ldh-str
+ */
+ if (value_r != NULL) {
+ tagbuf = value;
+ } else {
+ tagbuf = t_str_new(16);
+ str_append_c(tagbuf, '[');
+ }
+ if (smtp_parser_parse_ldh_str(parser, tagbuf) <= 0 ||
+ parser->cur >= parser->end || *parser->cur != ':') {
+ parser->error = "Invalid address literal";
+ return -1;
+ }
+ if (strcasecmp(str_c(tagbuf)+1, "IPv6") == 0)
+ ipv6 = TRUE;
+ else if (value_r == NULL) {
+ parser->error = t_strdup_printf(
+ "Unsupported %s address literal",
+ str_c(tagbuf)+1);
+ return -1;
+ }
+ parser->cur++;
+ if (value_r != NULL)
+ str_append_c(value, ':');
+
+ /* 1*dcontent */
+ pblock = parser->cur;
+ while (parser->cur < parser->end &&
+ smtp_char_is_dcontent(*parser->cur))
+ parser->cur++;
+
+ if (parser->cur == pblock) {
+ parser->error = "Empty address literal";
+ return -1;
+ }
+ if (value_r != NULL)
+ str_append_data(value, pblock, parser->cur - pblock);
+
+ if (ipv6) {
+ i_zero(&ip6);
+ if (inet_pton(AF_INET6, t_strndup(pblock,
+ parser->cur - pblock), &ip6) <= 0) {
+ parser->error = "Invalid IPv6 address literal";
+ return -1;
+ }
+ if (ip_r != NULL) {
+ ip_r->family = AF_INET6;
+ ip_r->u.ip6 = ip6;
+ }
+ }
+ }
+
+ /* ']' */
+ if (parser->cur >= parser->end) {
+ parser->error = "Missing ']' at end of address literal";
+ return -1;
+ } else if (*parser->cur != ']') {
+ parser->error = "Invalid character in address literal";
+ return -1;
+ }
+
+ parser->cur++;
+ if (value_r != NULL) {
+ str_append_c(value, ']');
+ *value_r = str_c(value);
+ }
+ return 1;
+}
+
+int smtp_parser_parse_quoted_string(struct smtp_parser *parser,
+ const char **value_r)
+{
+ string_t *value = NULL;
+ const unsigned char *pbegin;
+
+ /* Quoted-string = DQUOTE *QcontentSMTP DQUOTE
+ QcontentSMTP = qtextSMTP / quoted-pairSMTP
+ quoted-pairSMTP = %d92 %d32-126
+ ; i.e., backslash followed by any ASCII
+ ; graphic (including itself) or SPace
+ qtextSMTP = %d32-33 / %d35-91 / %d93-126
+ ; i.e., within a quoted string, any
+ ; ASCII graphic or space is permitted
+ ; without blackslash-quoting except
+ ; double-quote and the backslash itself.
+ */
+
+ /* DQUOTE */
+ if (parser->cur >= parser->end || *parser->cur != '"')
+ return 0;
+ parser->cur++;
+
+ if (value_r != NULL)
+ value = t_str_new(256);
+
+ /* *QcontentSMTP */
+ while (parser->cur < parser->end) {
+ pbegin = parser->cur;
+ while (parser->cur < parser->end &&
+ smtp_char_is_qtext(*parser->cur)) {
+ /* qtextSMTP */
+ parser->cur++;
+ }
+
+ if (value_r != NULL)
+ str_append_data(value, pbegin, parser->cur - pbegin);
+
+ if (parser->cur >= parser->end || *parser->cur != '\\')
+ break;
+ parser->cur++;
+
+ /* quoted-pairSMTP */
+ if (parser->cur >= parser->end ||
+ !smtp_char_is_qpair(*parser->cur)) {
+ parser->error =
+ "Invalid character after '\\' in quoted string";
+ return -1;
+ }
+
+ if (value_r != NULL)
+ str_append_c(value, *parser->cur);
+ parser->cur++;
+ }
+
+ /* DQUOTE */
+ if (parser->cur >= parser->end) {
+ parser->error = "Premature end of quoted string";
+ return -1;
+ }
+ if (*parser->cur != '"') {
+ parser->error = "Invalid character in quoted string";
+ return -1;
+ }
+ parser->cur++;
+ if (value_r != NULL)
+ *value_r = str_c(value);
+ return 1;
+}
+
+static int
+smtp_parser_skip_atom(struct smtp_parser *parser)
+{
+ /* Atom = 1*atext */
+
+ if (parser->cur >= parser->end || !smtp_char_is_atext(*parser->cur))
+ return 0;
+ parser->cur++;
+
+ while (parser->cur < parser->end && smtp_char_is_atext(*parser->cur))
+ parser->cur++;
+ return 1;
+}
+
+int smtp_parser_parse_atom(struct smtp_parser *parser,
+ const char **value_r)
+{
+ const unsigned char *pbegin = parser->cur;
+ int ret;
+
+ if ((ret=smtp_parser_skip_atom(parser)) <= 0)
+ return ret;
+
+ if (value_r != NULL)
+ *value_r = t_strndup(pbegin, parser->cur - pbegin);
+ return 1;
+}
+
+int smtp_parser_parse_string(struct smtp_parser *parser,
+ const char **value_r)
+{
+ int ret;
+
+ /* String = Atom / Quoted-string */
+
+ if ((ret=smtp_parser_parse_quoted_string(parser, value_r)) != 0)
+ return ret;
+ return smtp_parser_parse_atom(parser, value_r);
+}
+
+static bool
+smtp_parse_xtext_hexdigit(const unsigned char digit,
+ unsigned char *hexvalue)
+{
+ switch (digit) {
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ *hexvalue = (*hexvalue) << 4;
+ *hexvalue += digit - '0';
+ break;
+ case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
+ *hexvalue = (*hexvalue) << 4;
+ *hexvalue += digit - 'A' + 10;
+ break;
+ default:
+ return FALSE;
+ }
+ return TRUE;
+}
+
+int smtp_parser_parse_xtext(struct smtp_parser *parser,
+ string_t *out)
+{
+ unsigned char hexchar;
+
+ /* xtext = *( xchar / hexchar )
+ xchar = any ASCII CHAR between "!" (33) and "~" (126) inclusive,
+ except for "+" and "=".
+ hexchar = ASCII "+" immediately followed by two upper case
+ hexadecimal digits
+ */
+ if (parser->cur >= parser->end ||
+ (!smtp_char_is_xtext(*parser->cur) && *parser->cur != '+'))
+ return 0;
+
+ while (parser->cur < parser->end) {
+ const unsigned char *pbegin = parser->cur;
+
+ while (parser->cur < parser->end &&
+ smtp_char_is_xtext(*parser->cur))
+ parser->cur++;
+
+ if (out != NULL)
+ str_append_data(out, pbegin, parser->cur - pbegin);
+
+ if (parser->cur >= parser->end || *parser->cur != '+')
+ break;
+ parser->cur++;
+
+ hexchar = 0;
+ if (smtp_parse_xtext_hexdigit(*parser->cur, &hexchar)) {
+ parser->cur++;
+ if (smtp_parse_xtext_hexdigit(*parser->cur, &hexchar)) {
+ parser->cur++;
+ if (out != NULL)
+ str_append_c(out, hexchar);
+ continue;
+ }
+ }
+
+ parser->error = "Invalid hexchar after '+' in xtext";
+ return -1;
+ }
+
+ return 1;
+}
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