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authorWerner Koch <wk@gnupg.org>2018-05-31 12:59:40 +0200
committerWerner Koch <wk@gnupg.org>2018-05-31 12:59:40 +0200
commit874e391665405fc413a69f2ffacdb94bb08da7ff (patch)
treed101254c8ce2cbd0b2df4cc6407436f46fbdfe40 /g10/mainproc.c
parentgpg: Ignore the multiple message override options. (diff)
downloadgnupg2-874e391665405fc413a69f2ffacdb94bb08da7ff.tar.xz
gnupg2-874e391665405fc413a69f2ffacdb94bb08da7ff.zip
gpg: Print a hint on how to decrypt a non-mdc message anyway.
* g10/mainproc.c (proc_encrypted): Print a hint for legacy ciphers w/o MDC. Also print a dedicated status error code Signed-off-by: Werner Koch <wk@gnupg.org>
Diffstat (limited to 'g10/mainproc.c')
-rw-r--r--g10/mainproc.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/g10/mainproc.c b/g10/mainproc.c
index 0303a527d..cf22210a3 100644
--- a/g10/mainproc.c
+++ b/g10/mainproc.c
@@ -751,8 +751,25 @@ proc_encrypted (CTX c, PACKET *pkt)
* used. To avoid attacks changing an MDC message to a non-MDC
* message, we fail here. */
log_error (_("WARNING: message was not integrity protected\n"));
- if (opt.verbose > 1)
- log_info ("decryption forced to fail\n");
+ if (!pkt->pkt.encrypted->mdc_method
+ && (openpgp_cipher_get_algo_blklen (c->dek->algo) == 8
+ || c->dek->algo == CIPHER_ALGO_TWOFISH))
+ {
+ /* Before 2.2.8 we did not fail hard for a missing MDC if
+ * one of the old ciphers where used. Although these cases
+ * are rare in practice we print a hint on how to decrypt
+ * such messages. */
+ log_string
+ (GPGRT_LOGLVL_INFO,
+ _("Hint: If this message was created before the year 2003 it is\n"
+ "likely that this message is legitimate. This is because back\n"
+ "then integrity protection was not widely used.\n"));
+ log_info (_("Use the option '%s' to decrypt anyway.\n"),
+ "--ignore-mdc-error");
+ write_status_errcode ("nomdc_with_legacy_cipher",
+ GPG_ERR_DECRYPT_FAILED);
+ }
+ log_info (_("decryption forced to fail!\n"));
write_status (STATUS_DECRYPTION_FAILED);
}
else if (!result || (gpg_err_code (result) == GPG_ERR_BAD_SIGNATURE