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NFSD: Update the NFSv2 WRITE argument decoder to use struct xdr_stream

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Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-10-21 12:18:36 -04:00
parent 8c293ef993
commit a51b5b737a
1 changed files with 21 additions and 31 deletions
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52
fs/nfsd/nfsxdr.c
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@ -266,46 +266,36 @@ nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
int
nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
{
struct xdr_stream *xdr = &rqstp->rq_arg_stream;
struct nfsd_writeargs *args = rqstp->rq_argp;
unsigned int len, hdr, dlen;
struct kvec *head = rqstp->rq_arg.head;
struct kvec *tail = rqstp->rq_arg.tail;
u32 beginoffset, totalcount;
size_t remaining;
p = decode_fh(p, &args->fh);
if (!p)
if (!svcxdr_decode_fhandle(xdr, &args->fh))
return 0;
/* beginoffset is ignored */
if (xdr_stream_decode_u32(xdr, &beginoffset) < 0)
return 0;
if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
return 0;
/* totalcount is ignored */
if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
return 0;
p++; /* beginoffset */
args->offset = ntohl(*p++); /* offset */
p++; /* totalcount */
len = args->len = ntohl(*p++);
/*
* The protocol specifies a maximum of 8192 bytes.
*/
if (len > NFSSVC_MAXBLKSIZE_V2)
/* opaque data */
if (xdr_stream_decode_u32(xdr, &args->len) < 0)
return 0;
/*
* Check to make sure that we got the right number of
* bytes.
*/
hdr = (void*)p - head->iov_base;
if (hdr > head->iov_len)
if (args->len > NFSSVC_MAXBLKSIZE_V2)
return 0;
dlen = head->iov_len + rqstp->rq_arg.page_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;
args->first.iov_base = xdr->p;
args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
args->first.iov_base = (void *)p;
args->first.iov_len = head->iov_len - hdr;
return 1;
}