From b0b2d05fd0609d504236e5429cef421a35237bd6 Mon Sep 17 00:00:00 2001
From: Baptiste Daroussin <bapt@FreeBSD.org>
Date: Wed, 6 Dec 2017 22:08:35 +0000
Subject: [PATCH] Split body of mails not respecting RFC2822

For mails which has a body not respecting RFC2822 (which often happen with
crontabs) try to split by words finding the last space before 1000's character

If no spaces are found then consider the mail to be malformed anyway

PR:		208261
---
 contrib/dma/mail.c | 87 +++++++++++++++++++++++++++++++---------------
 1 file changed, 59 insertions(+), 28 deletions(-)

diff --git a/contrib/dma/mail.c b/contrib/dma/mail.c
index 842072c55242..bdfa7b0b7094 100644
--- a/contrib/dma/mail.c
+++ b/contrib/dma/mail.c
@@ -41,6 +41,8 @@
 
 #include "dma.h"
 
+#define MAX_LINE_RFC822	1000
+
 void
 bounce(struct qitem *it, const char *reason)
 {
@@ -341,19 +343,47 @@ parse_addrs(struct parse_state *ps, char *s, struct queue *queue)
 	goto again;
 }
 
+static int
+writeline(struct queue *queue, const char *line, ssize_t linelen)
+{
+	ssize_t len;
+
+	while (linelen > 0) {
+		len = linelen;
+		if (linelen > MAX_LINE_RFC822) {
+			len = MAX_LINE_RFC822 - 10;
+		}
+
+		if (fwrite(line, len, 1, queue->mailf) != 1)
+			return (-1);
+
+		if (linelen <= MAX_LINE_RFC822)
+			break;
+
+		if (fwrite("\n", 1, 1, queue->mailf) != 1)
+			return (-1);
+
+		line += MAX_LINE_RFC822 - 10;
+		linelen = strlen(line);
+	}
+	return (0);
+}
+
 int
 readmail(struct queue *queue, int nodot, int recp_from_header)
 {
 	struct parse_state parse_state;
-	char line[1000];	/* by RFC2822 */
-	size_t linelen;
+	char *line = NULL;
+	ssize_t linelen;
+	size_t linecap = 0;
+	char newline[MAX_LINE_RFC822];
 	size_t error;
 	int had_headers = 0;
 	int had_from = 0;
 	int had_messagid = 0;
 	int had_date = 0;
-	int had_last_line = 0;
 	int nocopy = 0;
+	int ret = -1;
 
 	parse_state.state = NONE;
 
@@ -372,24 +402,17 @@ readmail(struct queue *queue, int nodot, int recp_from_header)
 		return (-1);
 
 	while (!feof(stdin)) {
-		if (fgets(line, sizeof(line) - 1, stdin) == NULL)
+		newline[0] = '\0';
+		if ((linelen = getline(&line, &linecap, stdin)) <= 0)
 			break;
-		if (had_last_line)
-			errlogx(EX_DATAERR, "bad mail input format:"
-				" from %s (uid %d) (envelope-from %s)",
-				username, useruid, queue->sender);
-		linelen = strlen(line);
-		if (linelen == 0 || line[linelen - 1] != '\n') {
-			/*
-			 * This line did not end with a newline character.
-			 * If we fix it, it better be the last line of
-			 * the file.
-			 */
-			line[linelen] = '\n';
-			line[linelen + 1] = 0;
-			had_last_line = 1;
-		}
+
 		if (!had_headers) {
+			if (linelen > MAX_LINE_RFC822) {
+				/* XXX also split headers */
+				errlogx(EX_DATAERR, "bad mail input format:"
+				    " from %s (uid %d) (envelope-from %s)",
+				    username, useruid, queue->sender);
+			}
 			/*
 			 * Unless this is a continuation, switch of
 			 * the Bcc: nocopy flag.
@@ -430,31 +453,39 @@ readmail(struct queue *queue, int nodot, int recp_from_header)
 			while (!had_date || !had_messagid || !had_from) {
 				if (!had_date) {
 					had_date = 1;
-					snprintf(line, sizeof(line), "Date: %s\n", rfc822date());
+					snprintf(newline, sizeof(newline), "Date: %s\n", rfc822date());
 				} else if (!had_messagid) {
 					/* XXX msgid, assign earlier and log? */
 					had_messagid = 1;
-					snprintf(line, sizeof(line), "Message-Id: <%"PRIxMAX".%s.%"PRIxMAX"@%s>\n",
+					snprintf(newline, sizeof(newline), "Message-Id: <%"PRIxMAX".%s.%"PRIxMAX"@%s>\n",
 						 (uintmax_t)time(NULL),
 						 queue->id,
 						 (uintmax_t)random(),
 						 hostname());
 				} else if (!had_from) {
 					had_from = 1;
-					snprintf(line, sizeof(line), "From: <%s>\n", queue->sender);
+					snprintf(newline, sizeof(newline), "From: <%s>\n", queue->sender);
 				}
-				if (fwrite(line, strlen(line), 1, queue->mailf) != 1)
-					return (-1);
+				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
+					goto fail;
 			}
-			strcpy(line, "\n");
+			strlcpy(newline, "\n", sizeof(newline));
 		}
 		if (!nodot && linelen == 2 && line[0] == '.')
 			break;
 		if (!nocopy) {
-			if (fwrite(line, strlen(line), 1, queue->mailf) != 1)
-				return (-1);
+			if (newline[0]) {
+				if (fwrite(newline, strlen(newline), 1, queue->mailf) != 1)
+					goto fail;
+			} else {
+				if (writeline(queue, line, linelen) != 0)
+					goto fail;
+			}
 		}
 	}
 
-	return (0);
+	ret = 0;
+fail:
+	free(line);
+	return (ret);
 }