Gitweb:
https://git.exim.org/exim.git/commitdiff/65fe780259d0009354b5dfc9a4f1b48ad6513db2
Commit: 65fe780259d0009354b5dfc9a4f1b48ad6513db2
Parent: 5f17d2f09733cc77355841fbf095a95186cc9fe5
Author: Guillaume Outters <guillaume-exim@???>
AuthorDate: Mon Jul 6 22:31:51 2020 +0100
Committer: Jeremy Harris <jgh146exb@???>
CommitDate: Mon Jul 6 23:28:30 2020 +0100
Fix DKIM signing to always ;-terminate. Bug 2295
---
doc/doc-txt/ChangeLog | 5 +++
src/src/pdkim/pdkim.c | 116 +++++++++++++++++++-------------------------------
test/mail/4520.b12 | 6 +--
test/mail/4545.a | 6 +--
4 files changed, 55 insertions(+), 78 deletions(-)
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 7372ac2..8d368c8 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -81,6 +81,11 @@ JH/16 Bug 2615: Fix pause during message reception, on systems that have been
post-message next-tick-wait. Also change to using CLOCK_BOOTTIME if it
exists, just to get a clock slightly more aligned to reality.
+JH/17 Bug 2295: Fix DKIM signing to always semicolon-terminate. Although the
+ RFC says it is optional some validators care. The missing char was not
+ intended but triggered by a line-wrap alignement. Discovery and fix by
+ Guillaume Outters, hacked on by JH.
+
Exim version 4.94
-----------------
diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c
index 7712409..3a6ca4e 100644
--- a/src/src/pdkim/pdkim.c
+++ b/src/src/pdkim/pdkim.c
@@ -1111,14 +1111,14 @@ return string_catn(str, US"\r\n\t", 3);
/*
* RFC 5322 specifies that header line length SHOULD be no more than 78
- * lets make it so!
* pdkim_headcat
*
- * returns uschar * (not nul-terminated)
+ * Returns gstring (not nul-terminated) appending to one supplied
*
* col: this int holds and receives column number (octets since last '\n')
* str: partial string to append to
- * pad: padding, split line or space after before or after eg: ";"
+ * pad: padding, split line or space after before or after eg: ";".
+ * Only the initial charater is used.
* intro: - must join to payload eg "h=", usually the tag name
* payload: eg base64 data - long data can be split arbitrarily.
*
@@ -1127,7 +1127,7 @@ return string_catn(str, US"\r\n\t", 3);
* pairs and inside long values. it also always spaces or breaks after the
* "pad"
*
- * no guarantees are made for output given out-of range input. like tag
+ * No guarantees are made for output given out-of range input. like tag
* names longer than 78, or bogus col. Input is assumed to be free of line breaks.
*/
@@ -1135,92 +1135,64 @@ static gstring *
pdkim_headcat(int * col, gstring * str,
const uschar * pad, const uschar * intro, const uschar * payload)
{
-size_t l;
+int len, chomp, padded = 0;
-if (pad)
- {
- l = Ustrlen(pad);
- if (*col + l > 78)
- str = pdkim_hdr_cont(str, col);
- str = string_catn(str, pad, l);
- *col += l;
- }
-
-l = (pad?1:0) + (intro?Ustrlen(intro):0);
+/* If we can fit at least the pad at the end of current line, do it now.
+Otherwise, wrap if there is a pad. */
-if (*col + l > 78)
- { /*can't fit intro - start a new line to make room.*/
- str = pdkim_hdr_cont(str, col);
- l = intro?Ustrlen(intro):0;
- }
-
-l += payload ? Ustrlen(payload):0 ;
-
-while (l>77)
- { /* this fragment will not fit on a single line */
- if (pad)
- {
- str = string_catn(str, US" ", 1);
- *col += 1;
- pad = NULL; /* only want this once */
- l--;
- }
-
- if (intro)
- {
- size_t sl = Ustrlen(intro);
-
- str = string_catn(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL; /* only want this once */
- }
-
- if (payload)
+if (pad)
+ if (*col + 1 <= 78)
{
- size_t sl = Ustrlen(payload);
- size_t chomp = *col+sl < 77 ? sl : 78-*col;
-
- str = string_catn(str, payload, chomp);
- *col += chomp;
- payload += chomp;
- l -= chomp-1;
+ str = string_catn(str, pad, 1);
+ (*col)++;
+ pad = NULL;
+ padded = 1;
}
+ else
+ str = pdkim_hdr_cont(str, col);
- /* the while precondition tells us it didn't fit. */
- str = pdkim_hdr_cont(str, col);
- }
+/* Special case: if the whole addition does not fit at the end of the current
+line, but could fit on a new line, wrap to give it its full, dedicated line. */
-if (*col + l > 78)
+len = (pad ? 2 : padded)
+ + (intro ? Ustrlen(intro) : 0)
+ + (payload ? Ustrlen(payload) : 0);
+if (len <= 77 && *col+len > 78)
{
str = pdkim_hdr_cont(str, col);
- pad = NULL;
+ padded = 0;
}
+/* Either we already dealt with the pad or we know there is room */
+
if (pad)
{
+ str = string_catn(str, pad, 1);
str = string_catn(str, US" ", 1);
- *col += 1;
- pad = NULL;
+ *col += 2;
}
-
-if (intro)
+else if (padded && *col < 78)
{
- size_t sl = Ustrlen(intro);
-
- str = string_catn(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL;
+ str = string_catn(str, US" ", 1);
+ (*col)++;
}
-if (payload)
- {
- size_t sl = Ustrlen(payload);
+/* Call recursively with intro as payload: it gets the same, special treatment
+(that is, not split if < 78). */
- str = string_catn(str, payload, sl);
- *col += sl;
- }
+if (intro)
+ str = pdkim_headcat(col, str, NULL, NULL, intro);
+
+if (payload)
+ for (len = Ustrlen(payload); len; len -= chomp)
+ {
+ if (*col >= 78)
+ str = pdkim_hdr_cont(str, col);
+ chomp = *col+len > 78 ? 78 - *col : len;
+ str = string_catn(str, payload, chomp);
+ *col += chomp;
+ payload += chomp;
+ }
return str;
}
diff --git a/test/mail/4520.b12 b/test/mail/4520.b12
index e327a0d..392cee3 100644
--- a/test/mail/4520.b12
+++ b/test/mail/4520.b12
@@ -6,9 +6,9 @@ Received: from the.local.host.name ([ip4.ip4.ip4.ip4] helo=myhost.test.ex)
for b12@???; Tue, 2 Mar 1999 09:44:33 +0000
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=test.ex;
s=sel; h=X-mine:X-mine:From; bh=/Ab0giHZitYQbDhFszoqQRUkgqueaX9zatJttIU/plc=;
- b=VSF3Fmf7fHLpqKWgaG0t/RJdd+7JJNRN/+q7Gcz0xtIOjt5tL4Pfc4VDSeQYPq6e1pCcjvj79k
- 57of1wr0KIfk5FAvUZXPu3OtRm71y1X2rUaQB8c2Y2SROSMyaT3tsPzaEigiptIeeOkULYkFl2Hln
- 15ssCcfufIlOx4EQ9fQA=;
+ b=VSF3Fmf7fHLpqKWgaG0t/RJdd+7JJNRN/+q7Gcz0xtIOjt5tL4Pfc4VDSeQYPq6e1pCcjvj79k5
+ 7of1wr0KIfk5FAvUZXPu3OtRm71y1X2rUaQB8c2Y2SROSMyaT3tsPzaEigiptIeeOkULYkFl2Hln1
+ 5ssCcfufIlOx4EQ9fQA=;
Received: from CALLER by myhost.test.ex with local (Exim x.yz)
(envelope-from <CALLER@???>)
id 10HmbE-0005vi-00
diff --git a/test/mail/4545.a b/test/mail/4545.a
index b4a931f..18752a7 100644
--- a/test/mail/4545.a
+++ b/test/mail/4545.a
@@ -5,9 +5,9 @@ Received: from the.local.host.name ([ip4.ip4.ip4.ip4] helo=myhost.test.ex)
id 10HmaY-0005vi-00
for a@???; Tue, 2 Mar 1999 09:44:33 +0000
DKIM-Signature: v=1; a=ed25519-sha256; q=dns/txt; c=relaxed/relaxed; d=test.ex
- ; s=sed; h=From:To:Subject; bh=/Ab0giHZitYQbDhFszoqQRUkgqueaX9zatJttIU/plc=;
- b=5fhyD3EILDrnL4DnkD4hDaeis7+GSzL9GMHrhIDZJjuJ00WD5iI8SQ1q9rDfzFL/Kdw0VIyB4R
- Dq0a4H6HI+Bw==;
+ ; s=sed; h=From:To:Subject; bh=/Ab0giHZitYQbDhFszoqQRUkgqueaX9zatJttIU/plc=;
+ b=5fhyD3EILDrnL4DnkD4hDaeis7+GSzL9GMHrhIDZJjuJ00WD5iI8SQ1q9rDfzFL/Kdw0VIyB4RD
+ q0a4H6HI+Bw==;
Received: from CALLER by myhost.test.ex with local (Exim x.yz)
(envelope-from <CALLER@???>)
id 10HmaX-0005vi-00
