rxrpc: Fix rxkad token xdr encoding

The session key should be encoded with just the 8 data bytes and
no length; ENCODE_DATA precedes it with a 4 byte length, which
confuses some existing tools that try to parse this format.

Add an ENCODE_BYTES macro that does not include a length, and use
it for the key.  Also adjust the expected length.

Note that commit 774521f353 ("rxrpc: Fix an assertion in
rxrpc_read()") had fixed a BUG by changing the length rather than
fixing the encoding.  The original length was correct.

Fixes: 99455153d0 ("RxRPC: Parse security index 5 keys (Kerberos 5)")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Marc Dionne 2020-09-04 14:01:24 -03:00 committed by David Howells
parent 4296adc3e3
commit 56305118e0

View File

@ -1072,7 +1072,7 @@ static long rxrpc_read(const struct key *key,
switch (token->security_index) {
case RXRPC_SECURITY_RXKAD:
toksize += 9 * 4; /* viceid, kvno, key*2 + len, begin,
toksize += 8 * 4; /* viceid, kvno, key*2, begin,
* end, primary, tktlen */
toksize += RND(token->kad->ticket_len);
break;
@ -1138,6 +1138,14 @@ static long rxrpc_read(const struct key *key,
memcpy((u8 *)xdr + _l, &zero, 4 - (_l & 3)); \
xdr += (_l + 3) >> 2; \
} while(0)
#define ENCODE_BYTES(l, s) \
do { \
u32 _l = (l); \
memcpy(xdr, (s), _l); \
if (_l & 3) \
memcpy((u8 *)xdr + _l, &zero, 4 - (_l & 3)); \
xdr += (_l + 3) >> 2; \
} while(0)
#define ENCODE64(x) \
do { \
__be64 y = cpu_to_be64(x); \
@ -1165,7 +1173,7 @@ static long rxrpc_read(const struct key *key,
case RXRPC_SECURITY_RXKAD:
ENCODE(token->kad->vice_id);
ENCODE(token->kad->kvno);
ENCODE_DATA(8, token->kad->session_key);
ENCODE_BYTES(8, token->kad->session_key);
ENCODE(token->kad->start);
ENCODE(token->kad->expiry);
ENCODE(token->kad->primary_flag);