From 91015d021b3dcbe21ad0e580a4f34c523abf9e72 Mon Sep 17 00:00:00 2001 From: Daniel Kahn Gillmor Date: Fri, 23 Oct 2015 17:46:57 -0400 Subject: [PATCH] gpg: Ensure all weak digest rejection notices are shown * g10/main.h: Add rejection_shown flag to each weakhash struct * g10/misc.c (print_digest_algo_note, additional_weak_digest): Do not treat MD5 separately; (print_digest_rejected_note): Use weakhash.rejection_shown instead of static shown. * g10/options.h (opt): Change from additional_weak_digests to weak_digests. * g10/sig-check.c: Do not treat MD5 separately. * g10/gpg.c (main): Explicitly set MD5 as weak. * g10/gpgv.c (main): Explicitly set MD5 as weak. -- Previously, only one weak digest rejection message was shown, of whichever was the first type encountered. This meant that if "gpg --weak-digest SHA224" encountered both an MD5 digest and a SHA224 digest, it would only show the user that the MD5 digest was rejected. In order to let the user know which algorithms were rejected, we needed to move the "shown" flag into a per-weak-algorithm location. Given this additional complication, it made no sense to continue to treat MD5 specially, so it is added as a default weak algorithm in the same opt.weak_digests data structure as any other. Signed-Off-By: Daniel Kahn Gillmor --- g10/gpg.c | 3 ++- g10/gpgv.c | 2 ++ g10/main.h | 1 + g10/misc.c | 49 ++++++++++++++++++++++++------------------------- g10/options.h | 2 +- g10/sig-check.c | 11 ++--------- 6 files changed, 32 insertions(+), 36 deletions(-) diff --git a/g10/gpg.c b/g10/gpg.c index ff6e59f60..c18edd0dd 100644 --- a/g10/gpg.c +++ b/g10/gpg.c @@ -2216,7 +2216,8 @@ main (int argc, char **argv) set_homedir (default_homedir ()); opt.passphrase_repeat = 1; opt.emit_version = 1; /* Limit to the major number. */ - opt.additional_weak_digests = NULL; + opt.weak_digests = NULL; + additional_weak_digest("MD5"); /* Check whether we have a config file on the command line. */ orig_argc = argc; diff --git a/g10/gpgv.c b/g10/gpgv.c index ec09706b6..9a6dbd6d6 100644 --- a/g10/gpgv.c +++ b/g10/gpgv.c @@ -169,11 +169,13 @@ main( int argc, char **argv ) opt.batch = 1; opt.homedir = default_homedir (); + opt.weak_digests = NULL; tty_no_terminal(1); tty_batchmode(1); dotlock_disable (); gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0); + additional_weak_digest("MD5"); pargs.argc = &argc; pargs.argv = &argv; diff --git a/g10/main.h b/g10/main.h index a50c85c03..cb79a71e9 100644 --- a/g10/main.h +++ b/g10/main.h @@ -72,6 +72,7 @@ struct groupitem struct weakhash { enum gcry_md_algos algo; + int rejection_shown; struct weakhash *next; }; diff --git a/g10/misc.c b/g10/misc.c index 93ddaa042..5c77714d3 100644 --- a/g10/misc.c +++ b/g10/misc.c @@ -307,7 +307,6 @@ print_cipher_algo_note (cipher_algo_t algo) void print_digest_algo_note (digest_algo_t algo) { - int deprecated = 0; const enum gcry_md_algos galgo = map_md_openpgp_to_gcry (algo); const struct weakhash *weak; @@ -322,34 +321,38 @@ print_digest_algo_note (digest_algo_t algo) gcry_md_algo_name (galgo)); } } - else if(algo == DIGEST_ALGO_MD5) - deprecated = 1; else - for (weak = opt.additional_weak_digests; weak != NULL; weak = weak->next) + for (weak = opt.weak_digests; weak != NULL; weak = weak->next) if (weak->algo == galgo) - deprecated = 1; - - if (deprecated) - { - es_fflush (es_stdout); - log_info (_("WARNING: digest algorithm %s is deprecated\n"), - gcry_md_algo_name (galgo)); - } + { + es_fflush (es_stdout); + log_info (_("WARNING: digest algorithm %s is deprecated\n"), + gcry_md_algo_name (galgo)); + } } void print_digest_rejected_note (enum gcry_md_algos algo) { - static int shown; + struct weakhash* weak; + int show = 1; + for (weak = opt.weak_digests; weak; weak = weak->next) + if (weak->algo == algo) + { + if (weak->rejection_shown) + show = 0; + else + weak->rejection_shown = 1; + break; + } - if (!shown) + if (show) { es_fflush (es_stdout); log_info (_("Note: signatures using the %s algorithm are rejected\n"), gcry_md_algo_name(algo)); - shown = 1; } } @@ -1699,9 +1702,6 @@ additional_weak_digest (const char* digestname) struct weakhash *weak = NULL; const enum gcry_md_algos algo = string_to_digest_algo(digestname); - if (algo == GCRY_MD_MD5) - return; /* MD5 is always considered weak, no need to add it. */ - if (algo == GCRY_MD_NONE) { log_error(_("Unknown weak digest '%s'\n"), digestname); @@ -1709,15 +1709,14 @@ additional_weak_digest (const char* digestname) } /* Check to ensure it's not already present. */ - for (weak = opt.additional_weak_digests; weak != NULL; weak = weak->next) - { - if (algo == weak->algo) - return; - } + for (weak = opt.weak_digests; weak; weak = weak->next) + if (algo == weak->algo) + return; /* Add it to the head of the list. */ weak = xmalloc(sizeof(*weak)); weak->algo = algo; - weak->next = opt.additional_weak_digests; - opt.additional_weak_digests = weak; + weak->rejection_shown = 0; + weak->next = opt.weak_digests; + opt.weak_digests = weak; } diff --git a/g10/options.h b/g10/options.h index 0c674e6a5..4c7a5db9e 100644 --- a/g10/options.h +++ b/g10/options.h @@ -169,7 +169,7 @@ struct prefitem_t *personal_cipher_prefs; prefitem_t *personal_digest_prefs; prefitem_t *personal_compress_prefs; - struct weakhash *additional_weak_digests; + struct weakhash *weak_digests; int no_perm_warn; int no_mdc_warn; char *temp_dir; diff --git a/g10/sig-check.c b/g10/sig-check.c index f912c0ce2..2cfc5da50 100644 --- a/g10/sig-check.c +++ b/g10/sig-check.c @@ -360,19 +360,12 @@ check_signature_end (PKT_public_key *pk, PKT_signature *sig, return rc; if (!opt.flags.allow_weak_digest_algos) - { - if (sig->digest_algo == GCRY_MD_MD5) + for (weak = opt.weak_digests; weak; weak = weak->next) + if (sig->digest_algo == weak->algo) { print_digest_rejected_note(sig->digest_algo); return GPG_ERR_DIGEST_ALGO; } - for (weak = opt.additional_weak_digests; weak; weak = weak->next) - if (sig->digest_algo == weak->algo) - { - print_digest_rejected_note(sig->digest_algo); - return GPG_ERR_DIGEST_ALGO; - } - } /* Make sure the digest algo is enabled (in case of a detached signature). */