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From e52e4517853c3bc574d9468ca9ad3414e5271004 Mon Sep 17 00:00:00 2001
From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Date: Tue, 4 Mar 2025 23:56:30 -0500
Subject: gpg: Verify Text mode Signatures over binary Literal Data Packets
* tests/openpgp/issue7539{.scm,-signer.asc,message.asc}: Add test
with text-mode Signature over binary Literal Data Packet.
* tests/openpgp/Makefile.am: include 7539 test materials.
* g10/filter.h: add textmode and seen_cr members to
md_filter_context_t
* g10/mainproc.c (proc_plaintext): set mfx.textmode if the signature
is over a text document.
* g10/mdfilter.c (md_filter): when mfx.textmode is set, normalize line
endings to CRLF. (free_md_filter_context): clean up textmode and
seen_cr
* g10/plaintext.c (handle_plaintext): when mfx.textmode is set,
normalize line endings to CRLF.
--
GnuPG does not produce text signatures over binary literal data
packets, but the OpenPGP standard permits them, and other OpenPGP
implementations may produce them.
See the discussion starting at
https://mailarchive.ietf.org/arch/msg/openpgp/RLMBugGhg_c9xT7zmDrkBklRZB8/
This fix still doesn't handle the even-more-obscure struture where
there are both text and binary signatures over a binary literal data
packet, like so:
OPS0 OPS1 LITb SIG1 SIG0
But a more complete fix would be more complex (it would require, for
instance, multiple message digest handles), and this initial fix is
still a substantial improvement over the status quo.
GnuPG-bug-id: 7539
Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
g10/filter.h | 2 ++
g10/mainproc.c | 20 +++++++++++++++-----
g10/mdfilter.c | 15 +++++++++++++--
g10/plaintext.c | 28 ++++++++++++++++++++++++++--
tests/openpgp/Makefile.am | 7 +++++--
tests/openpgp/issue7539-message.asc | 8 ++++++++
tests/openpgp/issue7539-signer.asc | 9 +++++++++
tests/openpgp/issue7539.scm | 29 +++++++++++++++++++++++++++++
8 files changed, 107 insertions(+), 11 deletions(-)
create mode 100644 tests/openpgp/issue7539-message.asc
create mode 100644 tests/openpgp/issue7539-signer.asc
create mode 100644 tests/openpgp/issue7539.scm
diff --git a/g10/filter.h b/g10/filter.h
index 4b4fc55ff..8e1662b4e 100644
--- a/g10/filter.h
+++ b/g10/filter.h
@@ -27,6 +27,8 @@ typedef struct {
gcry_md_hd_t md; /* catch all */
gcry_md_hd_t md2; /* if we want to calculate an alternate hash */
size_t maxbuf_size;
+ int textmode; /* 1 hashing needs to normalize line-endings to CRLF */
+ int seen_cr; /* 1 if last octet hashed was '\r' */
} md_filter_context_t;
typedef struct {
diff --git a/g10/mainproc.c b/g10/mainproc.c
index 8c13c99c1..6dc3d7490 100644
--- a/g10/mainproc.c
+++ b/g10/mainproc.c
@@ -971,9 +971,12 @@ proc_plaintext( CTX c, PACKET *pkt )
if (n->pkt->pkt.onepass_sig->digest_algo)
{
if (!opt.skip_verify)
- gcry_md_enable (c->mfx.md,
- n->pkt->pkt.onepass_sig->digest_algo);
-
+ {
+ gcry_md_enable (c->mfx.md,
+ n->pkt->pkt.onepass_sig->digest_algo);
+ if (n->pkt->pkt.onepass_sig->sig_class == 0x01)
+ c->mfx.textmode = 1;
+ }
any = 1;
}
}
@@ -992,7 +995,10 @@ proc_plaintext( CTX c, PACKET *pkt )
clearsig = (*data == 0x01);
for (data++, datalen--; datalen; datalen--, data++)
if (!opt.skip_verify)
- gcry_md_enable (c->mfx.md, *data);
+ {
+ gcry_md_enable (c->mfx.md, *data);
+ c->mfx.textmode = 1;
+ }
any = 1;
break; /* Stop here as one-pass signature packets are not
expected. */
@@ -1001,7 +1007,11 @@ proc_plaintext( CTX c, PACKET *pkt )
{
/* The SIG+LITERAL case that PGP used to use. */
if (!opt.skip_verify)
- gcry_md_enable (c->mfx.md, n->pkt->pkt.signature->digest_algo);
+ {
+ gcry_md_enable (c->mfx.md, n->pkt->pkt.signature->digest_algo);
+ if (n->pkt->pkt.signature->sig_class == 0x01)
+ c->mfx.textmode = 1;
+ }
any = 1;
}
}
diff --git a/g10/mdfilter.c b/g10/mdfilter.c
index f3318f15c..4872d9cb4 100644
--- a/g10/mdfilter.c
+++ b/g10/mdfilter.c
@@ -40,7 +40,7 @@ md_filter( void *opaque, int control,
{
size_t size = *ret_len;
md_filter_context_t *mfx = opaque;
- int i, rc=0;
+ int i, rc=0, n;
if( control == IOBUFCTRL_UNDERFLOW ) {
if( mfx->maxbuf_size && size > mfx->maxbuf_size )
@@ -48,7 +48,16 @@ md_filter( void *opaque, int control,
i = iobuf_read( a, buf, size );
if( i == -1 ) i = 0;
if( i ) {
- gcry_md_write(mfx->md, buf, i );
+ if (!mfx->textmode)
+ gcry_md_write(mfx->md, buf, i );
+ else
+ for (n = 0; n < i; n++)
+ {
+ if (buf[n] == '\n' && !mfx->seen_cr)
+ gcry_md_putc(mfx->md, '\r');
+ gcry_md_putc(mfx->md, buf[n]);
+ mfx->seen_cr = (buf[n] == '\r');
+ }
if( mfx->md2 )
gcry_md_write(mfx->md2, buf, i );
}
@@ -70,4 +79,6 @@ free_md_filter_context( md_filter_context_t *mfx )
mfx->md = NULL;
mfx->md2 = NULL;
mfx->maxbuf_size = 0;
+ mfx->textmode = 0;
+ mfx->seen_cr = 0;
}
diff --git a/g10/plaintext.c b/g10/plaintext.c
index c906d05b6..25da64a78 100644
--- a/g10/plaintext.c
+++ b/g10/plaintext.c
@@ -311,6 +311,7 @@ handle_plaintext (PKT_plaintext * pt, md_filter_context_t * mfx,
while (pt->len)
{
int len = pt->len > temp_size ? temp_size : pt->len;
+ int n;
len = iobuf_read (pt->buf, buffer, len);
if (len == -1)
{
@@ -321,7 +322,18 @@ handle_plaintext (PKT_plaintext * pt, md_filter_context_t * mfx,
goto leave;
}
if (mfx->md)
- gcry_md_write (mfx->md, buffer, len);
+ {
+ if (!mfx->textmode)
+ gcry_md_write (mfx->md, buffer, len);
+ else
+ for (n = 0; n < len; n++)
+ {
+ if (buffer[n] == '\n' && !mfx->seen_cr)
+ gcry_md_putc(mfx->md, '\r');
+ gcry_md_putc(mfx->md, buffer[n]);
+ mfx->seen_cr = (buffer[n] == '\r');
+ }
+ }
if (fp)
{
if (opt.max_output && (count += len) > opt.max_output)
@@ -409,12 +421,24 @@ handle_plaintext (PKT_plaintext * pt, md_filter_context_t * mfx,
* So, always assume EOF if iobuf_read returns less bytes
* then requested */
int len = iobuf_read (pt->buf, buffer, temp_size);
+ int n;
if (len == -1)
break;
if (len < temp_size)
eof_seen = 1;
if (mfx->md)
- gcry_md_write (mfx->md, buffer, len);
+ {
+ if (!mfx->textmode)
+ gcry_md_write (mfx->md, buffer, len);
+ else
+ for (n = 0; n < len; n++)
+ {
+ if (buffer[n] == '\n' && !mfx->seen_cr)
+ gcry_md_putc(mfx->md, '\r');
+ gcry_md_putc(mfx->md, buffer[n]);
+ mfx->seen_cr = (buffer[n] == '\r');
+ }
+ }
if (fp)
{
if (opt.max_output && (count += len) > opt.max_output)
diff --git a/tests/openpgp/Makefile.am b/tests/openpgp/Makefile.am
index ea8207e28..bf2f11a08 100644
--- a/tests/openpgp/Makefile.am
+++ b/tests/openpgp/Makefile.am
@@ -105,7 +105,8 @@ XTESTS = \
issue2417.scm \
issue2419.scm \
issue2929.scm \
- issue2941.scm
+ issue2941.scm \
+ issue7539.scm
# XXX: Currently, one cannot override automake's 'check' target. As a
@@ -178,7 +179,9 @@ TEST_FILES = pubring.asc secring.asc plain-1o.asc plain-2o.asc plain-3o.asc \
trust-pgp/david.sec.asc \
trust-pgp/frank.sec.asc \
trust-pgp/grace.sec.asc \
- trust-pgp/heidi.sec.asc
+ trust-pgp/heidi.sec.asc \
+ issue7539-signer.asc \
+ issue7539-message.asc
data_files = data-500 data-9000 data-32000 data-80000 plain-large
diff --git a/tests/openpgp/issue7539-message.asc b/tests/openpgp/issue7539-message.asc
new file mode 100644
index 000000000..d9627e9de
--- /dev/null
+++ b/tests/openpgp/issue7539-message.asc
@@ -0,0 +1,8 @@
+-----BEGIN PGP MESSAGE-----
+
+xA0DAQoWT96UsBf1XGsBywtiAAAAAAB0ZXN0CsJ1BAEWCgAdFiEE4nTJ+uve2SXH
+vtD4T96UsBf1XGsFAme5OzsACgkQT96UsBf1XGtKWAEAjmR2dUu8Jsvq+j3QArUQ
+J549CNsbbuHLLAhaE0C2zZMBAJD4hLT9KXxnpTINCAcgZfytWChkNP+qKqb4pV5N
+ItsH
+=OYzj
+-----END PGP MESSAGE-----
diff --git a/tests/openpgp/issue7539-signer.asc b/tests/openpgp/issue7539-signer.asc
new file mode 100644
index 000000000..170498e1e
--- /dev/null
+++ b/tests/openpgp/issue7539-signer.asc
@@ -0,0 +1,9 @@
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+
+xjMEZ7k39xYJKwYBBAHaRw8BAQdAOfCju+pxXLXR2WU7ItL1LdlJFfubUeXQPk33
+sqDgebXNCHRlc3Qga2V5wo8EEBYIADcCGQEFAme5N/cCGwMICwkIBwoNDAsFFQoJ
+CAsCFgIBJxYhBOJ0yfrr3tklx77Q+E/elLAX9VxrAAoJEE/elLAX9VxrJKcBAPzY
+8Ct8qZ2xbzMXMtHrnR+a2kYLVDA9U8xPtrzQOUcOAPoDW17PxLj0IyZBS7ewb2Zt
+bbZ7yHLYYKmrF2mAyBOiCA==
+=UNOn
+-----END PGP PUBLIC KEY BLOCK-----
diff --git a/tests/openpgp/issue7539.scm b/tests/openpgp/issue7539.scm
new file mode 100644
index 000000000..c84c40feb
--- /dev/null
+++ b/tests/openpgp/issue7539.scm
@@ -0,0 +1,29 @@
+#!/usr/bin/env gpgscm
+
+;; Copyright (C) 2025 Daniel Kahn Gillmor <dkg@fifthhorseman.net>
+;;
+;; This file is part of GnuPG.
+;;
+;; GnuPG is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3 of the License, or
+;; (at your option) any later version.
+;;
+;; GnuPG is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program; if not, see <https://www.gnu.org/licenses/>.
+
+(load (in-srcdir "tests" "openpgp" "defs.scm"))
+(setup-legacy-environment)
+
+(define keyfile (in-srcdir "tests" "openpgp" "issue7539-signer.asc"))
+(define msg (in-srcdir "tests" "openpgp" "issue7539-message.asc"))
+
+(info "Checking text Signature over binary Literal Data Packet")
+
+(call-check `(,@gpg --import ,keyfile))
+(call-check `(,@gpg --verify ,msg))
--
2.47.2
|
