[Pkg-gnupg-commit] [gnupg2] 30/42: gpg: Print a warning for too much data encrypted with 3DES et al.
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Wed Jan 3 18:25:55 UTC 2018
This is an automated email from the git hooks/post-receive script.
dkg pushed a commit to branch upstream
in repository gnupg2.
commit 416cf9e9be5d2daf0ef629208031989699b3653f
Author: Werner Koch <wk at gnupg.org>
Date: Wed Dec 13 13:02:34 2017 +0100
gpg: Print a warning for too much data encrypted with 3DES et al.
* g10/filter.h (cipher_filter_context_t): Remove unused filed
'create_mdc'. Turn field 'header' into a bit field. Add new fields
'short_blklen_warn' and 'short_blklen_count'.
* g10/cipher.c (write_header): Print a warning if MDC is not used.
(cipher_filter): Print a warning for long messages encrypted with a
short block length algorithm.
--
Note that to test this warning in a reliable way compression needs to
be disabled.
Signed-off-by: Werner Koch <wk at gnupg.org>
---
g10/cipher.c | 26 +++++++++++++++++++++++---
g10/filter.h | 5 +++--
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/g10/cipher.c b/g10/cipher.c
index 409d0ad..b950d0c 100644
--- a/g10/cipher.c
+++ b/g10/cipher.c
@@ -64,6 +64,11 @@ write_header (cipher_filter_context_t *cfx, iobuf_t a)
if (DBG_HASHING)
gcry_md_debug (cfx->mdc_hash, "creatmdc");
}
+ else if (!opt.no_mdc_warn)
+ {
+ log_info ("WARNING: "
+ "encrypting without integrity protection is dangerous\n");
+ }
write_status_printf (STATUS_BEGIN_ENCRYPTION, "%d %d",
ed.mdc_method, cfx->dek->algo);
@@ -91,7 +96,6 @@ write_header (cipher_filter_context_t *cfx, iobuf_t a)
BUG();
}
-
/* log_hexdump ("thekey", cfx->dek->key, cfx->dek->keylen); */
gcry_cipher_setkey (cfx->cipher_hd, cfx->dek->key, cfx->dek->keylen);
gcry_cipher_setiv (cfx->cipher_hd, NULL, 0);
@@ -101,7 +105,11 @@ write_header (cipher_filter_context_t *cfx, iobuf_t a)
gcry_cipher_encrypt (cfx->cipher_hd, temp, nprefix+2, NULL, 0);
gcry_cipher_sync (cfx->cipher_hd);
iobuf_write (a, temp, nprefix+2);
- cfx->header = 1;
+
+ cfx->short_blklen_warn = (blocksize < 16);
+ cfx->short_blklen_count = nprefix+2;
+
+ cfx->wrote_header = 1;
}
@@ -122,11 +130,23 @@ cipher_filter (void *opaque, int control, iobuf_t a, byte *buf, size_t *ret_len)
else if (control == IOBUFCTRL_FLUSH) /* encrypt */
{
log_assert (a);
- if (!cfx->header)
+ if (!cfx->wrote_header)
write_header (cfx, a);
if (cfx->mdc_hash)
gcry_md_write (cfx->mdc_hash, buf, size);
gcry_cipher_encrypt (cfx->cipher_hd, buf, size, NULL, 0);
+ if (cfx->short_blklen_warn)
+ {
+ cfx->short_blklen_count += size;
+ if (cfx->short_blklen_count > (150 * 1024 * 1024))
+ {
+ log_info ("WARNING: encrypting more than %d MiB with algorithm "
+ "%s should be avoided\n", 150,
+ openpgp_cipher_algo_name (cfx->dek->algo));
+ cfx->short_blklen_warn = 0; /* Don't show again. */
+ }
+ }
+
rc = iobuf_write (a, buf, size);
}
else if (control == IOBUFCTRL_FREE)
diff --git a/g10/filter.h b/g10/filter.h
index 275608d..9e4b1e5 100644
--- a/g10/filter.h
+++ b/g10/filter.h
@@ -92,10 +92,11 @@ typedef struct {
DEK *dek;
u32 datalen;
gcry_cipher_hd_t cipher_hd;
- int header;
+ unsigned int wrote_header : 1;
+ unsigned int short_blklen_warn : 1;
+ unsigned long short_blklen_count;
gcry_md_hd_t mdc_hash;
byte enchash[20];
- int create_mdc; /* flag will be set by the cipher filter */
} cipher_filter_context_t;
--
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/pkg-gnupg/gnupg2.git
More information about the Pkg-gnupg-commit
mailing list