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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>
This commit is contained in:
Werner Koch 2018-05-31 12:59:40 +02:00
parent d3d41146b3
commit 874e391665
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
1 changed files with 19 additions and 2 deletions
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21
g10/mainproc.c
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@ -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