bypass the rfc822 parser, append domain can be achieved in a much simpler way

1 files changed, 167 insertions, 58 deletions

diff --git a/smtpd/smtp_session.c b/smtpd/smtp_session.c
index 4f61f3da..447cf124 100644
--- a/smtpd/smtp_session.c
+++ b/smtpd/smtp_session.c
@@ -49,6 +49,8 @@
 
 #define DATA_HIWAT		65535
 
+#define APPEND_DOMAIN_BUFFER_SIZE       4096
+
 enum smtp_phase {
 	PHASE_INIT = 0,
 	PHASE_SETUP,
@@ -282,74 +284,181 @@ header_bcc_callback(const struct rfc2822_header *hdr, void *arg)
 }
 
 static void
-header_masquerade_callback(const struct rfc2822_header *hdr, void *arg)
+header_append_domain_buffer(char *buffer, char *domain, size_t len)
 {
-        struct smtp_session    *s = arg;
-        struct rfc822_parser    rp;
-        struct rfc2822_line    *l;
-        struct rfc822_address  *ra;
-        size_t                  len;
-        char                    buf[SMTPD_MAXLINESIZE];
-        int                     ret;
+	size_t	i;
+	int	escape, quote, comment, bracket;
+	int	has_domain, has_bracket, has_group;
+	int	pos_bracket, pos_component, pos_insert;
+	char	copy[APPEND_DOMAIN_BUFFER_SIZE];
+
+	i = 0;
+	escape = quote = comment = bracket = 0;
+	has_domain = has_bracket = has_group = 0;
+	pos_bracket = pos_insert = pos_component = 0;
+	for (i = 0; buffer[i]; ++i) {
+		if (buffer[i] == '(' && !escape && !quote)
+			comment++;
+		if (buffer[i] == '"' && !escape && !comment)
+			quote = !quote;
+		if (buffer[i] == ')' && !escape && !quote && comment)
+			comment--;
+		if (buffer[i] == '\\' && !escape && !comment && !quote)
+			escape = 1;
+		else
+			escape = 0;
+		if (buffer[i] == '<' && !escape && !comment && !quote && !bracket) {
+			bracket++;
+			has_bracket = 1;
+		}
+		if (buffer[i] == '>' && !escape && !comment && !quote && bracket) {
+			bracket--;
+			pos_bracket = i;
+		}
+		if (buffer[i] == '@' && !escape && !comment && !quote)
+			has_domain = 1;
+		if (buffer[i] == ':' && !escape && !comment && !quote)
+			has_group = 1;
+		if (! isspace(buffer[i]))
+			pos_component = i;
+	}
 
-        rfc822_parser_init(&rp);
-        TAILQ_FOREACH(l, &hdr->lines, next)
-            if (! rfc822_parser_feed(&rp, l->buffer))
-                    goto fail;
+	/* parse error, do not attempt to modify */
+	if (escape || quote || comment || bracket)
+		return;
 
-        len = strlen(hdr->name) + 1;
-	if (iobuf_fqueue(&s->obuf, "%s:", hdr->name) != (int)len) {
-                s->msgflags |= MF_ERROR_IO;
-                rfc822_parser_reset(&rp);
-                return;
+	/* domain already present, no need to modify */
+	if (has_domain)
+		return;
+
+	/* address is group, skip */
+	if (has_group)
+		return;
+
+	/* there's an address between brackets, just append domain */
+	if (has_bracket) {
+		pos_bracket--;
+		while (isspace(buffer[pos_bracket]))
+			pos_bracket--;
+		if (buffer[pos_bracket] == '<')
+			return;
+		pos_insert = pos_bracket + 1;
 	}
-        s->odatalen += len;
+	else {
+		/* otherwise append address to last component */
+		pos_insert = pos_component + 1;
 
-        TAILQ_FOREACH(ra, &rp.addresses, next) {
-                /* no address provided, append local host */
-                if (strchr(ra->address, '@') == NULL) {
-                        (void)strlcat(ra->address, "@", sizeof ra->address);
-                        if (strlcat(ra->address, s->listener->hostname,
-                                sizeof ra->address) >= sizeof ra->address) {
-				s->msgflags |= MF_ERROR_MALFORMED;
-				rfc822_parser_reset(&rp);
-				return;
+		/* empty address */
+                if (buffer[pos_component] == '\0' || isspace(buffer[pos_component]))
+                        return;
+	}
+
+	if (snprintf(copy, sizeof copy, "%.*s@%s%s",
+		(int)pos_insert, buffer,
+		domain,
+		buffer+pos_insert) >= (int)sizeof copy)
+		return;
+
+	memcpy(buffer, copy, len);
+}
+
+static void
+header_masquerade_callback(const struct rfc2822_header *hdr, void *arg)
+{
+	struct smtp_session    *s = arg;
+	struct rfc2822_line    *l;
+	size_t			i, j;
+	int			escape, quote, comment, skip;
+	size_t			len;
+	char			buffer[APPEND_DOMAIN_BUFFER_SIZE];
+
+	len = strlen(hdr->name) + 1;
+	if (iobuf_fqueue(&s->obuf, "%s:", hdr->name) != (int)len)
+		goto ioerror;
+	s->odatalen += len;
+
+	i = j = 0;
+	escape = quote = comment = skip = 0;
+	memset(buffer, 0, sizeof buffer);
+
+	TAILQ_FOREACH(l, &hdr->lines, next) {
+		for (i = 0; i < strlen(l->buffer); ++i) {
+			if (l->buffer[i] == '(' && !escape && !quote)
+				comment++;
+			if (l->buffer[i] == '"' && !escape && !comment)
+				quote = !quote;
+			if (l->buffer[i] == ')' && !escape && !quote && comment)
+				comment--;
+			if (l->buffer[i] == '\\' && !escape && !comment && !quote)
+				escape = 1;
+			else
+				escape = 0;
+
+			/* found a separator, buffer contains a full address */
+			if (l->buffer[i] == ',' && !escape && !quote && !comment) {
+				if (!skip && j + strlen(s->listener->hostname) + 1 < sizeof buffer)
+					header_append_domain_buffer(buffer, s->listener->hostname, sizeof buffer);
+				len = strlen(buffer) + 1;
+				if (iobuf_fqueue(&s->obuf, "%s,", buffer) != (int)len)
+					goto ioerror;
+				s->odatalen += len;
+				j = 0;
+				skip = 0;
+				memset(buffer, 0, sizeof buffer);
+			}
+			else {
+				if (skip) {
+					if (iobuf_fqueue(&s->obuf, "%c", l->buffer[i]) != (int)1)
+						goto ioerror;
+					s->odatalen += 1;
+				}
+				else {
+					buffer[j++] = l->buffer[i];
+					if (j == sizeof (buffer) - 1) {
+						len = strlen(buffer);
+						if (iobuf_fqueue(&s->obuf, "%s", buffer) != (int)len)
+							goto ioerror;
+						s->odatalen += len;
+						skip = 1;
+						j = 0;
+						memset(buffer, 0, sizeof buffer);
+					}
+				}
 			}
-                }
-
-                if (ra->name[0] == '\0') {
-                        ret = snprintf(buf, sizeof buf, "%s%s%s",
-                            TAILQ_FIRST(&rp.addresses) == ra ? " " : "\t",
-                            ra->address,
-                            TAILQ_LAST(&rp.addresses, addresses) == ra ? "" : ",");
-                }
-                else {
-                        ret = snprintf(buf, sizeof buf, "%s%s <%s>%s",
-                            TAILQ_FIRST(&rp.addresses) == ra ? " " : "\t",
-                            ra->name,
-                            ra->address,
-                            TAILQ_LAST(&rp.addresses, addresses) == ra ? "" : ",");
-                }
-                if (ret == -1 || ret >= (int)sizeof buf) {
-			s->msgflags |= MF_ERROR_MALFORMED;
-			rfc822_parser_reset(&rp);
-			return;
 		}
-
-		len = strlen(buf) + 1;
-		if (iobuf_fqueue(&s->obuf, "%s\n", buf) != (int)len) {
-			s->msgflags |= MF_ERROR_IO;
-			rfc822_parser_reset(&rp);
-			return;
+		if (skip) {
+			if (iobuf_fqueue(&s->obuf, "\n", l->buffer[i]) != (int)1)
+				goto ioerror;
+			s->odatalen += 1;
+		}
+		else {
+			buffer[j++] = '\n';
+			if (j == sizeof (buffer) - 1) {
+				len = strlen(buffer);
+				if (iobuf_fqueue(&s->obuf, "%s", buffer) != (int)len)
+					goto ioerror;
+				s->odatalen += len;
+				skip = 1;
+				j = 0;
+				memset(buffer, 0, sizeof buffer);
+			}
 		}
+	}
+
+	/* end of header, if buffer is not empty we'll process it */
+	if (buffer[0]) {
+		if (j + strlen(s->listener->hostname) + 1 < sizeof buffer)
+			header_append_domain_buffer(buffer, s->listener->hostname, sizeof buffer);
+		len = strlen(buffer);
+		if (iobuf_fqueue(&s->obuf, "%s", buffer) != (int)len)
+			goto ioerror;
 		s->odatalen += len;
-        }
-        rfc822_parser_reset(&rp);
-        return;
+	}
+	return;
 
-fail:
-        rfc822_parser_reset(&rp);
-        header_default_callback(hdr, arg);
+ioerror:
+	s->msgflags |= MF_ERROR_IO;
+	return;
 }
 
 static void