diff options
| -rw-r--r-- | doc/gpg.texi | 14 | ||||
| -rw-r--r-- | g10/gpg.c | 7 | ||||
| -rw-r--r-- | g10/options.h | 1 | ||||
| -rw-r--r-- | g10/sig-check.c | 16 | ||||
| -rwxr-xr-x | tests/openpgp/defs.inc | 1 |
5 files changed, 36 insertions, 3 deletions
diff --git a/doc/gpg.texi b/doc/gpg.texi index b926a8adb..91186f24a 100644 --- a/doc/gpg.texi +++ b/doc/gpg.texi @@ -2276,9 +2276,10 @@ a message that PGP 2.x will not be able to handle. Note that `PGP available, but the MIT release is a good common baseline. This option implies @option{--rfc1991 --disable-mdc ---no-force-v4-certs --escape-from-lines --force-v3-sigs --cipher-algo -IDEA --digest-algo MD5 --compress-algo ZIP}. It also disables -@option{--textmode} when encrypting. +--no-force-v4-certs --escape-from-lines --force-v3-sigs +--allow-weak-digest-algos --cipher-algo IDEA --digest-algo +MD5--compress-algo ZIP}. It also disables @option{--textmode} when +encrypting. @item --pgp6 @opindex pgp6 @@ -2734,6 +2735,13 @@ necessary to get as much data as possible out of the corrupt message. However, be aware that a MDC protection failure may also mean that the message was tampered with intentionally by an attacker. +@item --allow-weak-digest-algos +@opindex allow-weak-digest-algos +Signatures made with the broken MD5 algorithm are normally rejected +with an ``invalid digest algorithm'' message. This option allows the +verification of signatures made with such weak algorithms. + + @item --no-default-keyring @opindex no-default-keyring Do not add the default keyrings to the list of keyrings. Note that @@ -374,6 +374,7 @@ enum cmd_and_opt_values oDisableDSA2, oAllowMultipleMessages, oNoAllowMultipleMessages, + oAllowWeakDigestAlgos, oFakedSystemTime, oNoop @@ -768,6 +769,7 @@ static ARGPARSE_OPTS opts[] = { ARGPARSE_s_n (oDisableDSA2, "disable-dsa2", "@"), ARGPARSE_s_n (oAllowMultipleMessages, "allow-multiple-messages", "@"), ARGPARSE_s_n (oNoAllowMultipleMessages, "no-allow-multiple-messages", "@"), + ARGPARSE_s_n (oAllowWeakDigestAlgos, "allow-weak-digest-algos", "@"), /* These two are aliases to help users of the PGP command line product use gpg with minimal pain. Many commands are common @@ -3066,6 +3068,10 @@ main (int argc, char **argv) opt.flags.allow_multiple_messages=0; break; + case oAllowWeakDigestAlgos: + opt.flags.allow_weak_digest_algos = 1; + break; + case oFakedSystemTime: { time_t faked_time = isotime2epoch (pargs.r.ret_str); @@ -3280,6 +3286,7 @@ main (int argc, char **argv) opt.pgp2_workarounds = 1; opt.ask_sig_expire = 0; opt.ask_cert_expire = 0; + opt.flags.allow_weak_digest_algos = 1; xfree(def_digest_string); def_digest_string = xstrdup("md5"); xfree(s2k_digest_string); diff --git a/g10/options.h b/g10/options.h index 592e06698..c622a4639 100644 --- a/g10/options.h +++ b/g10/options.h @@ -228,6 +228,7 @@ struct unsigned int utf8_filename:1; unsigned int dsa2:1; unsigned int allow_multiple_messages:1; + unsigned int allow_weak_digest_algos:1; } flags; /* Linked list of ways to find a key if the key isn't on the local diff --git a/g10/sig-check.c b/g10/sig-check.c index a3075337c..0cbb7f2cc 100644 --- a/g10/sig-check.c +++ b/g10/sig-check.c @@ -266,6 +266,22 @@ do_check( PKT_public_key *pk, PKT_signature *sig, gcry_md_hd_t digest, if( (rc=do_check_messages(pk,sig,r_expired,r_revoked)) ) return rc; + if (sig->digest_algo == GCRY_MD_MD5 + && !opt.flags.allow_weak_digest_algos) + { + static int shown; + + if (!shown) + { + log_info + (_("Note: signatures using the %s algorithm are rejected\n"), + "MD5"); + shown = 1; + } + + return GPG_ERR_DIGEST_ALGO; + } + /* Make sure the digest algo is enabled (in case of a detached signature). */ gcry_md_enable (digest, sig->digest_algo); diff --git a/tests/openpgp/defs.inc b/tests/openpgp/defs.inc index 008d32a43..2faa4c25a 100755 --- a/tests/openpgp/defs.inc +++ b/tests/openpgp/defs.inc @@ -245,6 +245,7 @@ for f in gpg.conf gpg-agent.conf ; do gpg.conf) [ -n "${opt_always}" ] && echo "no-auto-check-trustdb" >>"$f" echo "agent-program $GPG_AGENT" >>"$f" + echo "allow-weak-digest-algos" >>"$f" ;; gpg-agent.conf) |