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rxrpc: Make the parsing of xdr payloads more coherent

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Make the parsing of xdr-encoded payloads, as passed to add_key, more
coherent.  Shuttling back and forth between various variables was a bit
hard to follow.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2020-09-27 11:17:03 +01:00
parent d5953f6543
commit 4c20c33340
1 changed files with 11 additions and 10 deletions
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21
net/rxrpc/key.c
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@ -135,7 +135,7 @@ static int rxrpc_preparse_xdr_rxkad(struct key_preparsed_payload *prep,
*/
static int rxrpc_preparse_xdr(struct key_preparsed_payload *prep)
{
const __be32 *xdr = prep->data, *token;
const __be32 *xdr = prep->data, *token, *p;
const char *cp;
unsigned int len, paddedlen, loop, ntoken, toklen, sec_ix;
size_t datalen = prep->datalen;
@ -189,20 +189,20 @@ static int rxrpc_preparse_xdr(struct key_preparsed_payload *prep)
goto not_xdr;
/* check each token wrapper */
token = xdr;
p = xdr;
loop = ntoken;
do {
if (datalen < 8)
goto not_xdr;
toklen = ntohl(*xdr++);
sec_ix = ntohl(*xdr);
toklen = ntohl(*p++);
sec_ix = ntohl(*p);
datalen -= 4;
_debug("token: [%x/%zx] %x", toklen, datalen, sec_ix);
paddedlen = (toklen + 3) & ~3;
if (toklen < 20 || toklen > datalen || paddedlen > datalen)
goto not_xdr;
datalen -= paddedlen;
xdr += paddedlen >> 2;
p += paddedlen >> 2;
} while (--loop > 0);
@ -214,17 +214,18 @@ static int rxrpc_preparse_xdr(struct key_preparsed_payload *prep)
* - we ignore the cellname, relying on the key to be correctly named
*/
do {
xdr = token;
toklen = ntohl(*xdr++);
token = xdr + ((toklen + 3) >> 2);
sec_ix = ntohl(*xdr++);
token = xdr;
xdr += (toklen + 3) / 4;
sec_ix = ntohl(*token++);
toklen -= 4;
_debug("TOKEN type=%u [%p-%p]", sec_ix, xdr, token);
_debug("TOKEN type=%x len=%x", sec_ix, toklen);
switch (sec_ix) {
case RXRPC_SECURITY_RXKAD:
ret = rxrpc_preparse_xdr_rxkad(prep, datalen, xdr, toklen);
ret = rxrpc_preparse_xdr_rxkad(prep, datalen, token, toklen);
if (ret != 0)
goto error;
break;