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NFSD: Update WRITE3arg decoder to use struct xdr_stream 

As part of the update, open code that sanity-checks the size of the
data payload against the length of the RPC Call message has to be
re-implemented to use xdr_stream infrastructure.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-10-22 11:14:55 -04:00
parent be63bd2ac6
commit c43b2f229a
1 changed files with 20 additions and 31 deletions
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51
fs/nfsd/nfs3xdr.c
View File

@ -405,52 +405,41 @@ nfs3svc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
int
nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd3_writeargs *args = rqstp->rq_argp;
unsigned int len, hdr, dlen;
u32 max_blocksize = svc_max_payload(rqstp);
struct kvec *head = rqstp->rq_arg.head;
struct kvec *tail = rqstp->rq_arg.tail;
size_t remaining;
p = decode_fh(p, &args->fh);
if (!p)
if (!svcxdr_decode_nfs_fh3(xdr, &args->fh))
return 0;
if (xdr_stream_decode_u64(xdr, &args->offset) < 0)
return 0;
if (xdr_stream_decode_u32(xdr, &args->count) < 0)
return 0;
if (xdr_stream_decode_u32(xdr, &args->stable) < 0)
return 0;
p = xdr_decode_hyper(p, &args->offset);
args->count = ntohl(*p++);
args->stable = ntohl(*p++);
len = args->len = ntohl(*p++);
if ((void *)p > head->iov_base + head->iov_len)
/* opaque data */
if (xdr_stream_decode_u32(xdr, &args->len) < 0)
return 0;
/*
* The count must equal the amount of data passed.
*/
/* request sanity */
if (args->count != args->len)
return 0;
/*
* Check to make sure that we got the right number of
* bytes.
*/
hdr = (void*)p - head->iov_base;
dlen = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len - hdr;
/*
* Round the length of the data which was specified up to
* the next multiple of XDR units and then compare that
* against the length which was actually received.
* Note that when RPCSEC/GSS (for example) is used, the
* data buffer can be padded so dlen might be larger
* than required. It must never be smaller.
*/
if (dlen < XDR_QUADLEN(len)*4)
remaining = head->iov_len + rqstp->rq_arg.page_len + tail->iov_len;
remaining -= xdr_stream_pos(xdr);
if (remaining < xdr_align_size(args->len))
return 0;
if (args->count > max_blocksize) {
args->count = max_blocksize;
len = args->len = max_blocksize;
args->len = max_blocksize;
}
args->first.iov_base = (void *)p;
args->first.iov_len = head->iov_len - hdr;
args->first.iov_base = xdr->p;
args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
return 1;
}