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gpg: Support decryption of the new AEAD packet 

* common/openpgpdefs.h (aead_algo_t): New.
(pkttype_t): Add PKT_ENCRYPTED_AEAD.
* g10/decrypt-data.c (struct decode_filter_context_s): Add fields for
AEAD.
(aead_set_nonce_and_ad): New.
(aead_checktag): New.
(decrypt_data): Support AEAD.
(aead_underflow): New.
(aead_decode_filter): New.
* g10/dek.h (DEK): Add field use_aead.  Turn use_mdc,
algo_info_printed, and symmetric into bit flags.
* g10/mainproc.c (struct mainproc_context): Add field
seen_pkt_encrypted_aead.
(release_list): Clear it.
(have_seen_pkt_encrypted_aead): New.
(symkey_decrypt_seskey): Support AEAD.
(proc_symkey_enc): Ditto.
(proc_encrypted): Ditto.
(proc_plaintext): Ditto.
* g10/misc.c (MY_GCRY_CIPHER_MODE_EAX): New.
(openpgp_aead_test_algo): New.
(openpgp_aead_algo_name): New.
(openpgp_aead_algo_info): New.
* g10/packet.h (PKT_symkey_enc): Add field use_aead.
(PKT_user_id): Add field flags.aead
(PKT_public_key): Ditto.
(PKT_encrypted): Add fields for AEAD.
* g10/parse-packet.c (parse): Handle PKT_ENCRYPTED_AEAD.
(parse_symkeyenc): Support AEAD.
(parse_encrypted): Ditto.
(dump_sig_subpkt): Dump AEAD preference packet.
(parse_encrypted_aead): New.
--

This patch allows to decrypt data encrypted using the new AEAD
mechanism as specified in rfc4880bis.  Although preferences are used
to enable this new mode, it is useful to have at least a decryption
option in case a user switches between GnuPG 2.2 and newer versions.

The new AEAD mechanism is much faster than the current CFB+MDC and
thus 2.2 will allow faster decryption of symmetric only decryption.

This patch is based on the current master (2.3) code base and includes
a few other patches.  In particular
commit 44be675b75
(gpg: More check for symmetric key encryption.)
is included.

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2020-04-16 08:06:27 +02:00
parent 144b95cc9d
commit 1dfe71c62b
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
10 changed files with 907 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
common/openpgpdefs.h
View File

@ -51,6 +51,7 @@ typedef enum
PKT_ATTRIBUTE = 17, /* PGP's attribute packet. */
PKT_ENCRYPTED_MDC = 18, /* Integrity protected encrypted data. */
PKT_MDC = 19, /* Manipulation detection code packet. */
PKT_ENCRYPTED_AEAD= 20, /* AEAD encrypted data packet. */
PKT_COMMENT = 61, /* new comment packet (GnuPG specific). */
PKT_GPG_CONTROL = 63 /* internal control packet (GnuPG specific). */
}
@ -125,6 +126,16 @@ typedef enum
sigsubpkttype_t;
/* Note that we encode the AEAD algo in a 3 bit field at some places. */
typedef enum
{
AEAD_ALGO_NONE = 0,
AEAD_ALGO_EAX = 1,
AEAD_ALGO_OCB = 2
}
aead_algo_t;
typedef enum
{
CIPHER_ALGO_NONE = 0,

3
doc/DETAILS
View File

@ -545,9 +545,10 @@ pkd:0:1024:B665B1435F4C2 .... FF26ABB:
actual key used for descryption. <fpr2> is the fingerprint of the
primary key. <otrust> is the letter with the ownertrust; this is
in general a 'u' which stands for ultimately trusted.
*** DECRYPTION_INFO <mdc_method> <sym_algo>
*** DECRYPTION_INFO <mdc_method> <sym_algo> [<aead_algo>]
Print information about the symmetric encryption algorithm and the
MDC method. This will be emitted even if the decryption fails.
For an AEAD algorithm AEAD_ALGO is not 0.
*** DECRYPTION_FAILED
The symmetric decryption failed - one reason could be a wrong

498
g10/decrypt-data.c
View File

@ -34,6 +34,8 @@
#include "../common/compliance.h"
static int aead_decode_filter (void *opaque, int control, iobuf_t a,
byte *buf, size_t *ret_len);
static int mdc_decode_filter ( void *opaque, int control, IOBUF a,
byte *buf, size_t *ret_len);
static int decode_filter ( void *opaque, int control, IOBUF a,
@ -53,6 +55,9 @@ struct decode_filter_context_s
/* The hash handle for use in MDC mode. */
gcry_md_hd_t mdc_hash;
/* The start IV for AEAD encryption. */
byte startiv[16];
/* The holdback buffer and its used length. For AEAD we need 32+1
* bytes but we use 48 byte. For MDC we need 22 bytes; here
* holdbacklen will either 0 or 22. */
@ -68,6 +73,27 @@ struct decode_filter_context_s
* 3 = premature EOF (general) */
unsigned int eof_seen : 2;
/* The actually used cipher algo for AEAD. */
byte cipher_algo;
/* The AEAD algo. */
byte aead_algo;
/* The encoded chunk byte for AEAD. */
byte chunkbyte;
/* The decoded CHUNKBYTE. */
uint64_t chunksize;
/* The chunk index for AEAD. */
uint64_t chunkindex;
/* The number of bytes in the current chunk. */
uint64_t chunklen;
/* The total count of decrypted plaintext octets. */
uint64_t total;
/* Remaining bytes in the packet according to the packet header.
* Not used if PARTIAL is true. */
size_t length;
@ -94,6 +120,99 @@ release_dfx_context (decode_filter_ctx_t dfx)
}
/* Set the nonce and the additional data for the current chunk. This
* also reset the decryption machinery so that the handle can be
* used for a new chunk. If FINAL is set the final AEAD chunk is
* processed. */
static gpg_error_t
aead_set_nonce_and_ad (decode_filter_ctx_t dfx, int final)
{
gpg_error_t err;
unsigned char ad[21];
unsigned char nonce[16];
int i;
switch (dfx->aead_algo)
{
case AEAD_ALGO_OCB:
memcpy (nonce, dfx->startiv, 15);
i = 7;
break;
case AEAD_ALGO_EAX:
memcpy (nonce, dfx->startiv, 16);
i = 8;
break;
default:
BUG ();
}
nonce[i++] ^= dfx->chunkindex >> 56;
nonce[i++] ^= dfx->chunkindex >> 48;
nonce[i++] ^= dfx->chunkindex >> 40;
nonce[i++] ^= dfx->chunkindex >> 32;
nonce[i++] ^= dfx->chunkindex >> 24;
nonce[i++] ^= dfx->chunkindex >> 16;
nonce[i++] ^= dfx->chunkindex >> 8;
nonce[i++] ^= dfx->chunkindex;
if (DBG_CRYPTO)
log_printhex ("nonce:", nonce, i);
err = gcry_cipher_setiv (dfx->cipher_hd, nonce, i);
if (err)
return err;
ad[0] = (0xc0 | PKT_ENCRYPTED_AEAD);
ad[1] = 1;
ad[2] = dfx->cipher_algo;
ad[3] = dfx->aead_algo;
ad[4] = dfx->chunkbyte;
ad[5] = dfx->chunkindex >> 56;
ad[6] = dfx->chunkindex >> 48;
ad[7] = dfx->chunkindex >> 40;
ad[8] = dfx->chunkindex >> 32;
ad[9] = dfx->chunkindex >> 24;
ad[10]= dfx->chunkindex >> 16;
ad[11]= dfx->chunkindex >> 8;
ad[12]= dfx->chunkindex;
if (final)
{
ad[13] = dfx->total >> 56;
ad[14] = dfx->total >> 48;
ad[15] = dfx->total >> 40;
ad[16] = dfx->total >> 32;
ad[17] = dfx->total >> 24;
ad[18] = dfx->total >> 16;
ad[19] = dfx->total >> 8;
ad[20] = dfx->total;
}
if (DBG_CRYPTO)
log_printhex ("authdata:", ad, final? 21 : 13);
return gcry_cipher_authenticate (dfx->cipher_hd, ad, final? 21 : 13);
}
/* Helper to check the 16 byte tag in TAGBUF. The FINAL flag is only
* for debug messages. */
static gpg_error_t
aead_checktag (decode_filter_ctx_t dfx, int final, const void *tagbuf)
{
gpg_error_t err;
if (DBG_FILTER)
log_printhex ("tag:", tagbuf, 16);
err = gcry_cipher_checktag (dfx->cipher_hd, tagbuf, 16);
if (err)
{
log_error ("gcry_cipher_checktag%s failed: %s\n",
final? " (final)":"", gpg_strerror (err));
return err;
}
if (DBG_FILTER)
log_debug ("%stag is valid\n", final?"final ":"");
return 0;
}
/****************
* Decrypt the data, specified by ED with the key DEK.
@ -160,7 +279,96 @@ decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
blocksize = openpgp_cipher_get_algo_blklen (dek->algo);
if ( !blocksize || blocksize > 16 )
log_fatal ("unsupported blocksize %u\n", blocksize );
if (1)
if (ed->aead_algo)
{
enum gcry_cipher_modes ciphermode;
unsigned int startivlen;
if (blocksize != 16)
{
rc = gpg_error (GPG_ERR_CIPHER_ALGO);
goto leave;
}
rc = openpgp_aead_algo_info (ed->aead_algo, &ciphermode, &startivlen);
if (rc)
goto leave;
log_assert (startivlen <= sizeof dfx->startiv);
if (ed->chunkbyte > 56)
{
log_error ("invalid AEAD chunkbyte %u\n", ed->chunkbyte);
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
/* Read the Start-IV. */
if (ed->len)
{
for (i=0; i < startivlen && ed->len; i++, ed->len--)
{
if ((c=iobuf_get (ed->buf)) == -1)
break;
dfx->startiv[i] = c;
}
}
else
{
for (i=0; i < startivlen; i++ )
if ( (c=iobuf_get (ed->buf)) == -1 )
break;
else
dfx->startiv[i] = c;
}
if (i != startivlen)
{
log_error ("Start-IV in AEAD packet too short (%d/%u)\n",
i, startivlen);
rc = gpg_error (GPG_ERR_TOO_SHORT);
goto leave;
}
dfx->cipher_algo = ed->cipher_algo;
dfx->aead_algo = ed->aead_algo;
dfx->chunkbyte = ed->chunkbyte;
dfx->chunksize = (uint64_t)1 << (dfx->chunkbyte + 6);
if (dek->algo != dfx->cipher_algo)
log_info ("Note: different cipher algorithms used (%s/%s)\n",
openpgp_cipher_algo_name (dek->algo),
openpgp_cipher_algo_name (dfx->cipher_algo));
rc = openpgp_cipher_open (&dfx->cipher_hd,
dfx->cipher_algo,
ciphermode,
GCRY_CIPHER_SECURE);
if (rc)
goto leave; /* Should never happen. */
if (DBG_CRYPTO)
log_printhex ("thekey:", dek->key, dek->keylen);
rc = gcry_cipher_setkey (dfx->cipher_hd, dek->key, dek->keylen);
if (gpg_err_code (rc) == GPG_ERR_WEAK_KEY)
{
log_info (_("WARNING: message was encrypted with"
" a weak key in the symmetric cipher.\n"));
rc = 0;
}
else if (rc)
{
log_error("key setup failed: %s\n", gpg_strerror (rc));
goto leave;
}
if (!ed->buf)
{
log_error(_("problem handling encrypted packet\n"));
goto leave;
}
}
else /* CFB encryption. */
{
nprefix = blocksize;
if ( ed->len && ed->len < (nprefix+2) )
@ -249,9 +457,11 @@ decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
}
dfx->refcount++;
dfx->partial = ed->is_partial;
dfx->partial = !!ed->is_partial;
dfx->length = ed->len;
if ( ed->mdc_method )
if (ed->aead_algo)
iobuf_push_filter ( ed->buf, aead_decode_filter, dfx );
else if (ed->mdc_method)
iobuf_push_filter ( ed->buf, mdc_decode_filter, dfx );
else
iobuf_push_filter ( ed->buf, decode_filter, dfx );
@ -324,7 +534,6 @@ decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
/* log_printhex("MDC calc:", gcry_md_read (dfx->mdc_hash,0), datalen); */
}
leave:
release_dfx_context (dfx);
return rc;
@ -385,6 +594,287 @@ fill_buffer (decode_filter_ctx_t dfx, iobuf_t stream,
}
/* The core of the AEAD decryption. This is the underflow function of
* the aead_decode_filter. */
static gpg_error_t
aead_underflow (decode_filter_ctx_t dfx, iobuf_t a, byte *buf, size_t *ret_len)
{
const size_t size = *ret_len; /* The allocated size of BUF. */
gpg_error_t err;
size_t totallen = 0; /* The number of bytes to return on success or EOF. */
size_t off = 0; /* The offset into the buffer. */
size_t len; /* The current number of bytes in BUF+OFF. */
log_assert (size > 48); /* Our code requires at least this size. */
/* Copy the rest from the last call of this function into BUF. */
len = dfx->holdbacklen;
dfx->holdbacklen = 0;
memcpy (buf, dfx->holdback, len);
if (DBG_FILTER)
log_debug ("aead_underflow: size=%zu len=%zu%s%s\n", size, len,
dfx->partial? " partial":"", dfx->eof_seen? " eof":"");
/* Read and fill up BUF. We need to watch out for an EOF so that we
* can detect the last chunk which is commonly shorter than the
* chunksize. After the last data byte from the last chunk 32 more
* bytes are expected for the last chunk's tag and the following
* final chunk's tag. To detect the EOF we need to try reading at least
* one further byte; however we try to read 16 extra bytes to avoid
* single byte reads in some lower layers. The outcome is that we
* have up to 48 extra extra octets which we will later put into the
* holdback buffer for the next invocation (which handles the EOF
* case). */
len = fill_buffer (dfx, a, buf, size, len);
if (len < 32)
{
/* Not enough data for the last two tags. */
err = gpg_error (GPG_ERR_TRUNCATED);
goto leave;
}
if (dfx->eof_seen)
{
/* If have seen an EOF we copy only the last two auth tags into
* the holdback buffer. */
dfx->holdbacklen = 32;
memcpy (dfx->holdback, buf+len-32, 32);
len -= 32;
}
else
{
/* If have not seen an EOF we copy the entire extra 48 bytes
* into the holdback buffer for processing at the next call of
* this function. */
dfx->holdbacklen = len > 48? 48 : len;
memcpy (dfx->holdback, buf+len-dfx->holdbacklen, dfx->holdbacklen);
len -= dfx->holdbacklen;
}
/* log_printhex (dfx->holdback, dfx->holdbacklen, "holdback:"); */
/* Decrypt the buffer. This first requires a loop to handle the
* case when a chunk ends within the buffer. */
if (DBG_FILTER)
log_debug ("decrypt: chunklen=%ju total=%ju size=%zu len=%zu%s\n",
dfx->chunklen, dfx->total, size, len,
dfx->eof_seen? " eof":"");
while (len && dfx->chunklen + len >= dfx->chunksize)
{
size_t n = dfx->chunksize - dfx->chunklen;
byte tagbuf[16];
if (DBG_FILTER)
log_debug ("chunksize will be reached: n=%zu\n", n);
if (!dfx->chunklen)
{
/* First data for this chunk - prepare. */
err = aead_set_nonce_and_ad (dfx, 0);
if (err)
goto leave;
}
/* log_printhex (buf, n, "ciph:"); */
gcry_cipher_final (dfx->cipher_hd);
err = gcry_cipher_decrypt (dfx->cipher_hd, buf+off, n, NULL, 0);
if (err)
{
log_error ("gcry_cipher_decrypt failed (1): %s\n",
gpg_strerror (err));
goto leave;
}
/* log_printhex (buf, n, "plai:"); */
totallen += n;
dfx->chunklen += n;
dfx->total += n;
off += n;
len -= n;
if (DBG_FILTER)
log_debug ("ndecrypted: %zu (nchunk=%ju) bytes left: %zu at off=%zu\n",
totallen, dfx->chunklen, len, off);
/* Check the tag. */
if (len < 16)
{
/* The tag is not entirely in the buffer. Read the rest of
* the tag from the holdback buffer. Then shift the holdback
* buffer and fill it up again. */
memcpy (tagbuf, buf+off, len);
memcpy (tagbuf + len, dfx->holdback, 16 - len);
dfx->holdbacklen -= 16-len;
memmove (dfx->holdback, dfx->holdback + (16-len), dfx->holdbacklen);
if (dfx->eof_seen)
{
/* We should have the last chunk's tag in TAGBUF and the
* final tag in HOLDBACKBUF. */
if (len || dfx->holdbacklen != 16)
{
/* Not enough data for the last two tags. */
err = gpg_error (GPG_ERR_TRUNCATED);
goto leave;
}
}
else
{
len = 0;
dfx->holdbacklen = fill_buffer (dfx, a, dfx->holdback, 48,
dfx->holdbacklen);
if (dfx->holdbacklen < 32)
{
/* Not enough data for the last two tags. */
err = gpg_error (GPG_ERR_TRUNCATED);
goto leave;
}
}
}
else /* We already have the full tag. */
{
memcpy (tagbuf, buf+off, 16);
/* Remove that tag from the output. */
memmove (buf + off, buf + off + 16, len - 16);
len -= 16;
}
err = aead_checktag (dfx, 0, tagbuf);
if (err)
goto leave;
dfx->chunklen = 0;
dfx->chunkindex++;
continue;
}
/* The bulk decryption of our buffer. */
if (len)
{
if (!dfx->chunklen)
{
/* First data for this chunk - prepare. */
err = aead_set_nonce_and_ad (dfx, 0);
if (err)
goto leave;
}
if (dfx->eof_seen)
{
/* This is the last block of the last chunk. Its length may
* not be a multiple of the block length. */
gcry_cipher_final (dfx->cipher_hd);
}
err = gcry_cipher_decrypt (dfx->cipher_hd, buf + off, len, NULL, 0);
if (err)
{
log_error ("gcry_cipher_decrypt failed (2): %s\n",
gpg_strerror (err));
goto leave;
}
totallen += len;
dfx->chunklen += len;
dfx->total += len;
if (DBG_FILTER)
log_debug ("ndecrypted: %zu (nchunk=%ju)\n", totallen, dfx->chunklen);
}
if (dfx->eof_seen)
{
if (dfx->chunklen)
{
if (DBG_FILTER)
log_debug ("eof seen: holdback has the last and final tag\n");
log_assert (dfx->holdbacklen >= 32);
err = aead_checktag (dfx, 0, dfx->holdback);
if (err)
goto leave;
dfx->chunklen = 0;
dfx->chunkindex++;
off = 16;
}
else
{
if (DBG_FILTER)
log_debug ("eof seen: holdback has the final tag\n");
log_assert (dfx->holdbacklen >= 16);
off = 0;
}
/* Check the final chunk. */
err = aead_set_nonce_and_ad (dfx, 1);
if (err)
goto leave;
gcry_cipher_final (dfx->cipher_hd);
/* Decrypt an empty string (using HOLDBACK as a dummy). */
err = gcry_cipher_decrypt (dfx->cipher_hd, dfx->holdback, 0, NULL, 0);
if (err)
{
log_error ("gcry_cipher_decrypt failed (final): %s\n",
gpg_strerror (err));
goto leave;
}
err = aead_checktag (dfx, 1, dfx->holdback+off);
if (err)
goto leave;
err = gpg_error (GPG_ERR_EOF);
}
leave:
if (DBG_FILTER)
log_debug ("aead_underflow: returning %zu (%s)\n",
totallen, gpg_strerror (err));
/* In case of an auth error we map the error code to the same as
* used by the MDC decryption. */
if (gpg_err_code (err) == GPG_ERR_CHECKSUM)
err = gpg_error (GPG_ERR_BAD_SIGNATURE);
/* In case of an error we better wipe out the buffer than to convey
* partly decrypted data. */
if (err && gpg_err_code (err) != GPG_ERR_EOF)
memset (buf, 0, size);
*ret_len = totallen;
return err;
}
/* The IOBUF filter used to decrypt AEAD encrypted data. */
static int
aead_decode_filter (void *opaque, int control, IOBUF a,
byte *buf, size_t *ret_len)
{
decode_filter_ctx_t dfx = opaque;
int rc = 0;
if ( control == IOBUFCTRL_UNDERFLOW && dfx->eof_seen )
{
*ret_len = 0;
rc = -1;
}
else if ( control == IOBUFCTRL_UNDERFLOW )
{
log_assert (a);
rc = aead_underflow (dfx, a, buf, ret_len);
if (gpg_err_code (rc) == GPG_ERR_EOF)
rc = -1; /* We need to use the old convention in the filter. */
}
else if ( control == IOBUFCTRL_FREE )
{
release_dfx_context (dfx);
}
else if ( control == IOBUFCTRL_DESC )
{
mem2str (buf, "aead_decode_filter", *ret_len);
}
return rc;
}
static int
mdc_decode_filter (void *opaque, int control, IOBUF a,
byte *buf, size_t *ret_len)

24
g10/dek.h
View File

@ -19,21 +19,31 @@
#ifndef G10_DEK_H
#define G10_DEK_H
typedef struct
{
/* The algorithm (e.g., CIPHER_ALGO_AES). */
int algo;
/* The length of the key (in bytes). */
int keylen;
/* Whether we've already printed information about this key. This
is currently only used in decrypt_data() and only if we are in
verbose mode. */
int algo_info_printed;
int use_mdc;
* is currently only used in decrypt_data() and only if we are in
* verbose mode. */
unsigned int algo_info_printed : 1;
/* AEAD shall be used. The value is the AEAD algo. */
int use_aead : 4;
/* MDC shall be used. */
unsigned int use_mdc : 1;
/* This key was read from a SK-ESK packet (see proc_symkey_enc). */
int symmetric;
byte key[32]; /* This is the largest used keylen (256 bit). */
unsigned int symmetric : 1;
/* This is the largest used keylen (256 bit). */
byte key[32];
/* The cacheid for the S2K. */
char s2k_cacheid[1+16+1];
} DEK;

2
g10/encrypt.c
View File

@ -110,7 +110,7 @@ encrypt_seskey (DEK *dek, DEK **seskey, byte *enckey)
/* Shall we use the MDC? Yes - unless rfc-2440 compatibility is
* requested. */
* requested. Must return 1 or 0. */
int
use_mdc (pk_list_t pk_list,int algo)
{

6
g10/main.h
View File

@ -122,6 +122,12 @@ int openpgp_cipher_blocklen (cipher_algo_t algo);
int openpgp_cipher_test_algo(cipher_algo_t algo);
const char *openpgp_cipher_algo_name (cipher_algo_t algo);
gpg_error_t openpgp_aead_test_algo (aead_algo_t algo);
const char *openpgp_aead_algo_name (aead_algo_t algo);
gpg_error_t openpgp_aead_algo_info (aead_algo_t algo,
enum gcry_cipher_modes *r_mode,
unsigned int *r_noncelen);
pubkey_algo_t map_pk_gcry_to_openpgp (enum gcry_pk_algos algo);
int openpgp_pk_test_algo (pubkey_algo_t algo);
int openpgp_pk_test_algo2 (pubkey_algo_t algo, unsigned int use);

184
g10/mainproc.c
View File

@ -97,6 +97,7 @@ struct mainproc_context
int trustletter; /* Temporary usage in list_node. */
ulong symkeys; /* Number of symmetrically encrypted session keys. */
struct kidlist_item *pkenc_list; /* List of encryption packets. */
int seen_pkt_encrypted_aead; /* PKT_ENCRYPTED_AEAD packet seen. */
struct {
unsigned int sig_seen:1; /* Set to true if a signature packet
has been seen. */
@ -145,6 +146,7 @@ release_list( CTX c )
c->any.data = 0;
c->any.uncompress_failed = 0;
c->last_was_session_key = 0;
c->seen_pkt_encrypted_aead = 0;
xfree (c->dek);
c->dek = NULL;
}
@ -252,47 +254,111 @@ add_signature (CTX c, PACKET *pkt)
return 1;
}
static int
static gpg_error_t
symkey_decrypt_seskey (DEK *dek, byte *seskey, size_t slen)
{
gpg_error_t err;
gcry_cipher_hd_t hd;
enum gcry_cipher_modes ciphermode;
unsigned int noncelen, keylen;
if(slen < 17 || slen > 33)
if (dek->use_aead)
{
err = openpgp_aead_algo_info (dek->use_aead, &ciphermode, &noncelen);
if (err)
return err;
}
else
{
ciphermode = GCRY_CIPHER_MODE_CFB;
noncelen = 0;
}
/* Check that the session key has a size of 16 to 32 bytes. */
if ((dek->use_aead && (slen < (noncelen + 16 + 16)
|| slen > (noncelen + 32 + 16)))
|| (!dek->use_aead && (slen < 17 || slen > 33)))
{
log_error ( _("weird size for an encrypted session key (%d)\n"),
(int)slen);
return GPG_ERR_BAD_KEY;
return gpg_error (GPG_ERR_BAD_KEY);
}
if (openpgp_cipher_open (&hd, dek->algo, GCRY_CIPHER_MODE_CFB, 1))
BUG ();
if (gcry_cipher_setkey ( hd, dek->key, dek->keylen ))
BUG ();
gcry_cipher_setiv ( hd, NULL, 0 );
gcry_cipher_decrypt ( hd, seskey, slen, NULL, 0 );
gcry_cipher_close ( hd );
err = openpgp_cipher_open (&hd, dek->algo, ciphermode, 1);
if (!err)
err = gcry_cipher_setkey (hd, dek->key, dek->keylen);
if (!err)
err = gcry_cipher_setiv (hd, noncelen? seskey : NULL, noncelen);
if (err)
goto leave;
/* Here we can only test whether the algo given in decrypted
* session key is a valid OpenPGP algo. With 11 defined
* symmetric algorithms we will miss 4.3% of wrong passphrases
* here. The actual checking is done later during bulk
* decryption; we can't bring this check forward easily. */
if (openpgp_cipher_test_algo (seskey[0]))
return gpg_error (GPG_ERR_BAD_KEY);
if (dek->use_aead)
{
byte ad[4];
/* Now we replace the dek components with the real session key to
decrypt the contents of the sequencing packet. */
ad[0] = (0xc0 | PKT_SYMKEY_ENC);
ad[1] = 5;
ad[2] = dek->algo;
ad[3] = dek->use_aead;
err = gcry_cipher_authenticate (hd, ad, 4);
if (err)
goto leave;
gcry_cipher_final (hd);
keylen = slen - noncelen - 16;
err = gcry_cipher_decrypt (hd, seskey+noncelen, keylen, NULL, 0);
if (err)
goto leave;
err = gcry_cipher_checktag (hd, seskey+noncelen+keylen, 16);
if (err)
goto leave;
/* Now we replace the dek components with the real session key to
* decrypt the contents of the sequencing packet. */
if (keylen > DIM(dek->key))
{
err = gpg_error (GPG_ERR_TOO_LARGE);
goto leave;
}
dek->keylen = keylen;
memcpy (dek->key, seskey + noncelen, dek->keylen);
}
else
{
gcry_cipher_decrypt (hd, seskey, slen, NULL, 0);
dek->keylen=slen-1;
dek->algo=seskey[0];
/* Here we can only test whether the algo given in decrypted
* session key is a valid OpenPGP algo. With 11 defined
* symmetric algorithms we will miss 4.3% of wrong passphrases
* here. The actual checking is done later during bulk
* decryption; we can't bring this check forward easily. We
* need to use the GPG_ERR_CHECKSUM so that we won't run into
* the gnupg < 2.2 bug compatible case which would terminate the
* process on GPG_ERR_CIPHER_ALGO. Note that with AEAD (above)
* we will have a reliable test here. */
if (openpgp_cipher_test_algo (seskey[0])
|| openpgp_cipher_get_algo_keylen (seskey[0]) != slen - 1)
{
err = gpg_error (GPG_ERR_CHECKSUM);
goto leave;
}
if(dek->keylen > DIM(dek->key))
BUG ();
memcpy(dek->key, seskey + 1, dek->keylen);
/* Now we replace the dek components with the real session key to
* decrypt the contents of the sequencing packet. */
keylen = slen-1;
if (keylen > DIM(dek->key))
{
err = gpg_error (GPG_ERR_TOO_LARGE);
goto leave;
}
dek->algo = seskey[0];
dek->keylen = slen-1;
memcpy (dek->key, seskey + 1, dek->keylen);
}
/*log_hexdump( "thekey", dek->key, dek->keylen );*/
leave:
gcry_cipher_close (hd);
return 0;
}
@ -300,6 +366,7 @@ symkey_decrypt_seskey (DEK *dek, byte *seskey, size_t slen)
static void
proc_symkey_enc (CTX c, PACKET *pkt)
{
gpg_error_t err;
PKT_symkey_enc *enc;
enc = pkt->pkt.symkey_enc;
@ -309,15 +376,20 @@ proc_symkey_enc (CTX c, PACKET *pkt)
{
int algo = enc->cipher_algo;
const char *s = openpgp_cipher_algo_name (algo);
const char *a = (enc->aead_algo ? openpgp_aead_algo_name (enc->aead_algo)
/**/ : "CFB");
if (!openpgp_cipher_test_algo (algo))
{
if (!opt.quiet)
{
/* Note: TMPSTR is only used to avoid i18n changes. */
char *tmpstr = xstrconcat (s, ".", a, NULL);
if (enc->seskeylen)
log_info (_("%s encrypted session key\n"), s );
log_info (_("%s encrypted session key\n"), tmpstr);
else
log_info (_("%s encrypted data\n"), s );
log_info (_("%s encrypted data\n"), tmpstr);
xfree (tmpstr);
}
}
else
@ -349,6 +421,7 @@ proc_symkey_enc (CTX c, PACKET *pkt)
if (c->dek)
{
c->dek->symmetric = 1;
c->dek->use_aead = enc->aead_algo;
/* FIXME: This doesn't work perfectly if a symmetric key
comes before a public key in the message - if the
@ -359,9 +432,16 @@ proc_symkey_enc (CTX c, PACKET *pkt)
come later. */
if (enc->seskeylen)
{
if (symkey_decrypt_seskey (c->dek,
enc->seskey, enc->seskeylen))
err = symkey_decrypt_seskey (c->dek,
enc->seskey, enc->seskeylen);
if (err)
{
log_info ("decryption of the symmetrically encrypted"
" session key failed: %s\n",
gpg_strerror (err));
if (gpg_err_code (err) != GPG_ERR_BAD_KEY
&& gpg_err_code (err) != GPG_ERR_CHECKSUM)
log_fatal ("process terminated to be bug compatible\n");
if (c->dek->s2k_cacheid[0])
{
if (opt.debug)
@ -550,6 +630,9 @@ proc_encrypted (CTX c, PACKET *pkt)
int result = 0;
int early_plaintext = literals_seen;
if (pkt->pkttype == PKT_ENCRYPTED_AEAD)
c->seen_pkt_encrypted_aead = 1;
if (early_plaintext)
{
log_info (_("WARNING: multiple plaintexts seen\n"));
@ -683,7 +766,8 @@ proc_encrypted (CTX c, PACKET *pkt)
;
else if (!result
&& !opt.ignore_mdc_error
&& !pkt->pkt.encrypted->mdc_method)
&& !pkt->pkt.encrypted->mdc_method
&& !pkt->pkt.encrypted->aead_algo)
{
/* The message has been decrypted but does not carry an MDC.
* The option --ignore-mdc-error has also not been used. To
@ -712,17 +796,25 @@ proc_encrypted (CTX c, PACKET *pkt)
write_status (STATUS_DECRYPTION_FAILED);
}
else if (!result || (gpg_err_code (result) == GPG_ERR_BAD_SIGNATURE
&& !pkt->pkt.encrypted->aead_algo
&& opt.ignore_mdc_error))
{
/* All is fine or for an MDC message the MDC failed but the
* --ignore-mdc-error option is active. For compatibility
* reasons we issue GOODMDC also for AEAD messages. */
write_status (STATUS_DECRYPTION_OKAY);
if (opt.verbose > 1)
log_info(_("decryption okay\n"));
if (pkt->pkt.encrypted->mdc_method && !result)
if (pkt->pkt.encrypted->aead_algo)
write_status (STATUS_GOODMDC);
else if (pkt->pkt.encrypted->mdc_method && !result)
write_status (STATUS_GOODMDC);
else
log_info (_("WARNING: message was not integrity protected\n"));
}
else if (gpg_err_code (result) == GPG_ERR_BAD_SIGNATURE)
else if (gpg_err_code (result) == GPG_ERR_BAD_SIGNATURE
|| gpg_err_code (result) == GPG_ERR_TRUNCATED)
{
glo_ctrl.lasterr = result;
log_error (_("WARNING: encrypted message has been manipulated!\n"));
@ -732,6 +824,7 @@ proc_encrypted (CTX c, PACKET *pkt)
else
{
if ((gpg_err_code (result) == GPG_ERR_BAD_KEY
|| gpg_err_code (result) == GPG_ERR_CHECKSUM
|| gpg_err_code (result) == GPG_ERR_CIPHER_ALGO)
&& *c->dek->s2k_cacheid != '\0')
{
@ -761,6 +854,21 @@ proc_encrypted (CTX c, PACKET *pkt)
}
static int
have_seen_pkt_encrypted_aead( CTX c )
{
CTX cc;
for (cc = c; cc; cc = cc->anchor)
{
if (cc->seen_pkt_encrypted_aead)
return 1;
}
return 0;
}
static void
proc_plaintext( CTX c, PACKET *pkt )
{
@ -836,7 +944,7 @@ proc_plaintext( CTX c, PACKET *pkt )
}
}
if (!any && !opt.skip_verify)
if (!any && !opt.skip_verify && !have_seen_pkt_encrypted_aead(c))
{
/* This is for the old GPG LITERAL+SIG case. It's not legal
according to 2440, so hopefully it won't come up that often.
@ -1467,7 +1575,8 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC: proc_encrypted (c, pkt); break;
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD:proc_encrypted (c, pkt); break;
case PKT_COMPRESSED: rc = proc_compressed (c, pkt); break;
default: newpkt = 0; break;
}
@ -1483,6 +1592,7 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
case PKT_PUBKEY_ENC:
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD:
write_status_text( STATUS_UNEXPECTED, "0" );
rc = GPG_ERR_UNEXPECTED;
goto leave;
@ -1510,7 +1620,8 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC: proc_encrypted (c, pkt); break;
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD: proc_encrypted (c, pkt); break;
case PKT_PLAINTEXT: proc_plaintext (c, pkt); break;
case PKT_COMPRESSED: rc = proc_compressed (c, pkt); break;
case PKT_ONEPASS_SIG: newpkt = add_onepass_sig (c, pkt); break;
@ -1537,7 +1648,8 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC: proc_encrypted (c, pkt); break;
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD: proc_encrypted (c, pkt); break;
case PKT_PLAINTEXT: proc_plaintext (c, pkt); break;
case PKT_COMPRESSED: rc = proc_compressed (c, pkt); break;
case PKT_ONEPASS_SIG: newpkt = add_onepass_sig (c, pkt); break;

78
g10/misc.c
View File

@ -70,6 +70,10 @@
#include "../common/i18n.h"
#include "../common/zb32.h"
/* FIXME: Libgcrypt 1.9 will support EAX. Until we name this a
* requirement we hardwire the enum used for EAX. */
#define MY_GCRY_CIPHER_MODE_EAX 14
#ifdef ENABLE_SELINUX_HACKS
/* A object and a global variable to keep track of files marked as
@ -602,6 +606,80 @@ openpgp_cipher_algo_name (cipher_algo_t algo)
}
/* Return 0 if ALGO is supported. Return an error if not. */
gpg_error_t
openpgp_aead_test_algo (aead_algo_t algo)
{
/* FIXME: We currently have no easy way to test whether libgcrypt
* implements a mode. The only way we can do this is to open a
* cipher context with that mode and close it immediately. That is
* a bit costly. So we look at the libgcrypt version and assume
* nothing has been patched out. */
switch (algo)
{
case AEAD_ALGO_NONE:
break;
case AEAD_ALGO_EAX:
#if GCRYPT_VERSION_NUMBER < 0x010900
break;
#else
return 0;
#endif
case AEAD_ALGO_OCB:
return 0;
}
return gpg_error (GPG_ERR_INV_CIPHER_MODE);
}
/* Map the OpenPGP AEAD algorithm with ID ALGO to a string
* representation of the algorithm name. For unknown algorithm IDs
* this function returns "?". */
const char *
openpgp_aead_algo_name (aead_algo_t algo)
{
switch (algo)
{
case AEAD_ALGO_NONE: break;
case AEAD_ALGO_EAX: return "EAX";
case AEAD_ALGO_OCB: return "OCB";
}
return "?";
}
/* Return information for the AEAD algorithm ALGO. The corresponding
* Libgcrypt ciphermode is stored at R_MODE and the required number of
* octets for the nonce at R_NONCELEN. On error and error code is
* returned. Note that the taglen is always 128 bits. */
gpg_error_t
openpgp_aead_algo_info (aead_algo_t algo, enum gcry_cipher_modes *r_mode,
unsigned int *r_noncelen)
{
switch (algo)
{
case AEAD_ALGO_OCB:
*r_mode = GCRY_CIPHER_MODE_OCB;
*r_noncelen = 15;
break;
case AEAD_ALGO_EAX:
*r_mode = MY_GCRY_CIPHER_MODE_EAX;
*r_noncelen = 16;
break;
default:
log_error ("unsupported AEAD algo %d\n", algo);
return gpg_error (GPG_ERR_INV_CIPHER_MODE);
}
return 0;
}
/* Return 0 if ALGO is a supported OpenPGP public key algorithm. */
int
openpgp_pk_test_algo (pubkey_algo_t algo)

29
g10/packet.h
View File

@ -104,6 +104,8 @@ typedef struct {
be different from the algorithm that is used to encrypt the SED
packet.) */
byte cipher_algo;
/* The AEAD algorithm or 0 for CFB encryption. */
byte aead_algo;
/* The string-to-key specifier. */
STRING2KEY s2k;
/* The length of SESKEY in bytes or 0 if this packet does not
@ -111,7 +113,8 @@ typedef struct {
S2K function on the password is the session key. See RFC 4880,
Section 5.3.) */
byte seskeylen;
/* The session key as encrypted by the S2K specifier. */
/* The session key as encrypted by the S2K specifier. For AEAD this
* includes the nonce and the authentication tag. */
byte seskey[1];
} PKT_symkey_enc;
@ -297,6 +300,7 @@ typedef struct
struct
{
unsigned int mdc:1;
unsigned int aead:1;
unsigned int ks_modify:1;
unsigned int compacted:1;
unsigned int primary:2; /* 2 if set via the primary flag, 1 if calculated */
@ -393,6 +397,7 @@ typedef struct
struct
{
unsigned int mdc:1; /* MDC feature set. */
unsigned int aead:1; /* AEAD feature set. */
unsigned int disabled_valid:1;/* The next flag is valid. */
unsigned int disabled:1; /* The key has been disabled. */
unsigned int primary:1; /* This is a primary key. */
@ -463,12 +468,13 @@ typedef struct {
typedef struct {
/* Remaining length of encrypted data. */
u32 len;
/* When encrypting, the first block size bytes of data are random
data and the following 2 bytes are copies of the last two bytes
of the random data (RFC 4880, Section 5.7). This provides a
simple check that the key is correct. extralen is the size of
this extra data. This is used by build_packet when writing out
the packet's header. */
/* When encrypting in CFB mode, the first block size bytes of data
* are random data and the following 2 bytes are copies of the last
* two bytes of the random data (RFC 4880, Section 5.7). This
* provides a simple check that the key is correct. EXTRALEN is the
* size of this extra data or, in AEAD mode, the length of the
* headers and the tags. This is used by build_packet when writing
* out the packet's header. */
int extralen;
/* Whether the serialized version of the packet used / should use
the new format. */
@ -480,6 +486,15 @@ typedef struct {
/* If 0, MDC is disabled. Otherwise, the MDC method that was used
(currently, only DIGEST_ALGO_SHA1 is supported). */
byte mdc_method;
/* If 0, AEAD is not used. Otherwise, the used AEAD algorithm.
* MDC_METHOD (above) shall be zero if AEAD is used. */
byte aead_algo;
/* The cipher algo for/from the AEAD packet. 0 for other encryption
* packets. */
byte cipher_algo;
/* The chunk byte from the AEAD packet. */
byte chunkbyte;
/* An iobuf holding the data to be decrypted. (This is not used for
encryption!) */
iobuf_t buf;

140
g10/parse-packet.c
View File

@ -81,6 +81,9 @@ static int parse_compressed (IOBUF inp, int pkttype, unsigned long pktlen,
PACKET * packet, int new_ctb);
static int parse_encrypted (IOBUF inp, int pkttype, unsigned long pktlen,
PACKET * packet, int new_ctb, int partial);
static gpg_error_t parse_encrypted_aead (IOBUF inp, int pkttype,
unsigned long pktlen, PACKET *packet,
int partial);
static int parse_mdc (IOBUF inp, int pkttype, unsigned long pktlen,
PACKET * packet, int new_ctb);
static int parse_gpg_control (IOBUF inp, int pkttype, unsigned long pktlen,
@ -665,6 +668,7 @@ parse (parse_packet_ctx_t ctx, PACKET *pkt, int onlykeypkts, off_t * retpos,
case PKT_PLAINTEXT:
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD:
case PKT_COMPRESSED:
iobuf_set_partial_body_length_mode (inp, c & 0xff);
pktlen = 0; /* To indicate partial length. */
@ -852,6 +856,9 @@ parse (parse_packet_ctx_t ctx, PACKET *pkt, int onlykeypkts, off_t * retpos,
case PKT_MDC:
rc = parse_mdc (inp, pkttype, pktlen, pkt, new_ctb);
break;
case PKT_ENCRYPTED_AEAD:
rc = parse_encrypted_aead (inp, pkttype, pktlen, pkt, partial);
break;
case PKT_GPG_CONTROL:
rc = parse_gpg_control (inp, pkttype, pktlen, pkt, partial);
break;
@ -1127,19 +1134,17 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
{
PKT_symkey_enc *k;
int rc = 0;
int i, version, s2kmode, cipher_algo, hash_algo, seskeylen, minlen;
int i, version, s2kmode, cipher_algo, aead_algo, hash_algo, seskeylen, minlen;
if (pktlen < 4)
{
log_error ("packet(%d) too short\n", pkttype);
if (list_mode)
es_fprintf (listfp, ":symkey enc packet: [too short]\n");
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
goto too_short;
version = iobuf_get_noeof (inp);
pktlen--;
if (version != 4)
if (version == 4)
;
else if (version == 5)
;
else
{
log_error ("packet(%d) with unknown version %d\n", pkttype, version);
if (list_mode)
@ -1157,6 +1162,15 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
}
cipher_algo = iobuf_get_noeof (inp);
pktlen--;
if (version == 5)
{
aead_algo = iobuf_get_noeof (inp);
pktlen--;
}
else
aead_algo = 0;
if (pktlen < 2)
goto too_short;
s2kmode = iobuf_get_noeof (inp);
pktlen--;
hash_algo = iobuf_get_noeof (inp);
@ -1191,6 +1205,7 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
+ seskeylen - 1);
k->version = version;
k->cipher_algo = cipher_algo;
k->aead_algo = aead_algo;
k->s2k.mode = s2kmode;
k->s2k.hash_algo = hash_algo;
if (s2kmode == 1 || s2kmode == 3)
@ -1221,10 +1236,20 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
if (list_mode)
{
es_fprintf (listfp,
":symkey enc packet: version %d, cipher %d, s2k %d, hash %d",
version, cipher_algo, s2kmode, hash_algo);
":symkey enc packet: version %d, cipher %d, aead %d,"
"s2k %d, hash %d",
version, cipher_algo, aead_algo, s2kmode, hash_algo);
if (seskeylen)
es_fprintf (listfp, ", seskey %d bits", (seskeylen - 1) * 8);
{
/* To compute the size of the session key we need to know
* the size of the AEAD nonce which we may not know. Thus
* we show only the size of the entire encrypted session
* key. */
if (aead_algo)
es_fprintf (listfp, ", encrypted seskey %d bytes", seskeylen);
else
es_fprintf (listfp, ", seskey %d bits", (seskeylen - 1) * 8);
}
es_fprintf (listfp, "\n");
if (s2kmode == 1 || s2kmode == 3)
{
@ -1241,6 +1266,13 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
leave:
iobuf_skip_rest (inp, pktlen, 0);
return rc;
too_short:
log_error ("packet(%d) too short\n", pkttype);
if (list_mode)
es_fprintf (listfp, ":symkey enc packet: [too short]\n");
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
@ -1421,6 +1453,11 @@ dump_sig_subpkt (int hashed, int type, int critical,
for (i = 0; i < length; i++)
es_fprintf (listfp, " %d", buffer[i]);
break;
case SIGSUBPKT_PREF_AEAD:
es_fputs ("pref-aead-algos:", listfp);
for (i = 0; i < length; i++)
es_fprintf (listfp, " %d", buffer[i]);
break;
case SIGSUBPKT_REV_KEY:
es_fputs ("revocation key: ", listfp);
if (length < 22)
@ -1601,6 +1638,7 @@ parse_one_sig_subpkt (const byte * buffer, size_t n, int type)
case SIGSUBPKT_KEY_FLAGS:
case SIGSUBPKT_KS_FLAGS:
case SIGSUBPKT_PREF_SYM:
case SIGSUBPKT_PREF_AEAD:
case SIGSUBPKT_PREF_HASH:
case SIGSUBPKT_PREF_COMPR:
case SIGSUBPKT_POLICY:
@ -3253,6 +3291,9 @@ parse_encrypted (IOBUF inp, int pkttype, unsigned long pktlen,
ed->buf = NULL;
ed->new_ctb = new_ctb;
ed->is_partial = partial;
ed->aead_algo = 0;
ed->cipher_algo = 0; /* Only used with AEAD. */
ed->chunkbyte = 0; /* Only used with AEAD. */
if (pkttype == PKT_ENCRYPTED_MDC)
{
/* Fixme: add some pktlen sanity checks. */
@ -3344,6 +3385,81 @@ parse_mdc (IOBUF inp, int pkttype, unsigned long pktlen,
}
static gpg_error_t
parse_encrypted_aead (iobuf_t inp, int pkttype, unsigned long pktlen,
PACKET *pkt, int partial)
{
int rc = 0;
PKT_encrypted *ed;
unsigned long orig_pktlen = pktlen;
int version;
ed = pkt->pkt.encrypted = xtrymalloc (sizeof *pkt->pkt.encrypted);
if (!ed)
return gpg_error_from_syserror ();
ed->len = 0;
ed->extralen = 0; /* (only used in build_packet.) */
ed->buf = NULL;
ed->new_ctb = 1; /* (packet number requires a new CTB anyway.) */
ed->is_partial = partial;
ed->mdc_method = 0;
/* A basic sanity check. We need one version byte, one algo byte,
* one aead algo byte, one chunkbyte, at least 15 byte IV. */
if (orig_pktlen && pktlen < 19)
{
log_error ("packet(%d) too short\n", pkttype);
if (list_mode)
es_fputs (":aead encrypted packet: [too short]\n", listfp);
rc = gpg_error (GPG_ERR_INV_PACKET);
iobuf_skip_rest (inp, pktlen, partial);
goto leave;
}
version = iobuf_get_noeof (inp);
if (orig_pktlen)
pktlen--;
if (version != 1)
{
log_error ("aead encrypted packet with unknown version %d\n",
version);
if (list_mode)
es_fputs (":aead encrypted packet: [unknown version]\n", listfp);
/*skip_rest(inp, pktlen); should we really do this? */
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
ed->cipher_algo = iobuf_get_noeof (inp);
if (orig_pktlen)
pktlen--;
ed->aead_algo = iobuf_get_noeof (inp);
if (orig_pktlen)
pktlen--;
ed->chunkbyte = iobuf_get_noeof (inp);
if (orig_pktlen)
pktlen--;
/* Store the remaining length of the encrypted data. We read the
* rest during decryption. */
ed->len = pktlen;
if (list_mode)
{
es_fprintf (listfp, ":aead encrypted packet: cipher=%u aead=%u cb=%u\n",
ed->cipher_algo, ed->aead_algo, ed->chunkbyte);
if (orig_pktlen)
es_fprintf (listfp, "\tlength: %lu\n", orig_pktlen);
else
es_fprintf (listfp, "\tlength: unknown\n");
}
ed->buf = inp;
leave:
return rc;
}
/*
* This packet is internally generated by us (in armor.c) to transfer
* some information to the lower layer. To make sure that this packet