by Chuck Lever III

[permalink] [raw]

Subject: Re: [PATCH v1 07/42] NFSD: Update WRITE3arg decoder to use struct xdr_stream

> On Jan 22, 2021, at 1:47 PM, J. Bruce Fields <[email protected]> wrote:
>
> On Tue, Jan 05, 2021 at 10:30:18AM -0500, Chuck Lever wrote:
>> 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.
>
> I'm having a little trouble parsing that. Did you mean "write code"?

The WRITE payload size sanity-checking code has to be re-implemented.

> --b.
>
>>
>> Signed-off-by: Chuck Lever <[email protected]>
>> ---
>> fs/nfsd/nfs3xdr.c | 51 ++++++++++++++++++++-------------------------------
>> 1 file changed, 20 insertions(+), 31 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
>> index ff98eae5db81..0aafb096de91 100644
>> --- a/fs/nfsd/nfs3xdr.c
>> +++ b/fs/nfsd/nfs3xdr.c
>> @@ -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;
>> - 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)
>> + if (xdr_stream_decode_u64(xdr, &args->offset) < 0)
>> return 0;
>> - /*
>> - * The count must equal the amount of data passed.
>> - */
>> - if (args->count != args->len)
>> + if (xdr_stream_decode_u32(xdr, &args->count) < 0)
>> + return 0;
>> + if (xdr_stream_decode_u32(xdr, &args->stable) < 0)
>> 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)
>> + /* opaque data */
>> + if (xdr_stream_decode_u32(xdr, &args->len) < 0)
>> return 0;
>>
>> + /* request sanity */
>> + if (args->count != args->len)
>> + return 0;
>> + 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;
>> }
>>
>>

--
Chuck Lever

2021-01-22 22:19:18

by J. Bruce Fields

[permalink] [raw]

Subject: Re: [PATCH v1 00/42] Update NFSD XDR functions

ACK to the patches, looks good to me.--b.

On Tue, Jan 05, 2021 at 10:29:40AM -0500, Chuck Lever wrote:
> The long-term purpose is to convert the NFSD XDR encoder and decoder
> functions to use the struct xdr_stream API. This is a refactor and
> clean-up with few or no changes in behavior expected, but there are
> some long-term benefits:
>
> - More robust input sanitization in the NFSD decoders.
> - Help make it possible to use common kernel library functions with
> XDR stream APIs (for example, GSS-API).
> - Align the structure of the source code with the RFCs so it is
> easier to learn, verify, and maintain our XDR implementation.
> - Removal of more than a hundred hidden dprintk() call sites.
> - Removal of as much explicit manipulation of pages as possible to
> help make the eventual transition to xdr->bvecs smoother.
>
> The current series focuses on NFSv2 and NFSv3 decoder changes. Please
> review and comment!
>
> The full set of patches lives in a topic branch in my git repo:
>
> git://git.linux-nfs.org/projects/cel/cel-2.6.git nfsd-xdr_stream
>
>
> ---
>
> Chuck Lever (42):
> SUNRPC: Make trace_svc_process() display the RPC procedure symbolically
> SUNRPC: Display RPC procedure names instead of proc numbers
> SUNRPC: Move definition of XDR_UNIT
> NFSD: Update GETATTR3args decoder to use struct xdr_stream
> NFSD: Update ACCESS3arg decoder to use struct xdr_stream
> NFSD: Update READ3arg decoder to use struct xdr_stream
> NFSD: Update WRITE3arg decoder to use struct xdr_stream
> NFSD: Update READLINK3arg decoder to use struct xdr_stream
> NFSD: Fix returned READDIR offset cookie
> NFSD: Add helper to set up the pages where the dirlist is encoded
> NFSD: Update READDIR3args decoders to use struct xdr_stream
> NFSD: Update COMMIT3arg decoder to use struct xdr_stream
> NFSD: Update the NFSv3 DIROPargs decoder to use struct xdr_stream
> NFSD: Update the RENAME3args decoder to use struct xdr_stream
> NFSD: Update the LINK3args decoder to use struct xdr_stream
> NFSD: Update the SETATTR3args decoder to use struct xdr_stream
> NFSD: Update the CREATE3args decoder to use struct xdr_stream
> NFSD: Update the MKDIR3args decoder to use struct xdr_stream
> NFSD: Update the SYMLINK3args decoder to use struct xdr_stream
> NFSD: Update the MKNOD3args decoder to use struct xdr_stream
> NFSD: Update the NFSv2 GETATTR argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 READ argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 WRITE argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 READLINK argument decoder to use struct xdr_stream
> NFSD: Add helper to set up the pages where the dirlist is encoded
> NFSD: Update the NFSv2 READDIR argument decoder to use struct xdr_stream
> NFSD: Update NFSv2 diropargs decoding to use struct xdr_stream
> NFSD: Update the NFSv2 RENAME argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 LINK argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 SETATTR argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 CREATE argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 SYMLINK argument decoder to use struct xdr_stream
> NFSD: Remove argument length checking in nfsd_dispatch()
> NFSD: Update the NFSv2 GETACL argument decoder to use struct xdr_stream
> NFSD: Add an xdr_stream-based decoder for NFSv2/3 ACLs
> NFSD: Update the NFSv2 SETACL argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 ACL GETATTR argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 ACL ACCESS argument decoder to use struct xdr_stream
> NFSD: Clean up after updating NFSv2 ACL decoders
> NFSD: Update the NFSv3 GETACL argument decoder to use struct xdr_stream
> NFSD: Update the NFSv2 SETACL argument decoder to use struct xdr_stream
> NFSD: Clean up after updating NFSv3 ACL decoders
>
>
> fs/nfs_common/nfsacl.c | 52 +++
> fs/nfsd/nfs2acl.c | 62 ++--
> fs/nfsd/nfs3acl.c | 42 ++-
> fs/nfsd/nfs3proc.c | 71 +++--
> fs/nfsd/nfs3xdr.c | 538 ++++++++++++++++++--------------
> fs/nfsd/nfsproc.c | 74 +++--
> fs/nfsd/nfssvc.c | 34 --
> fs/nfsd/nfsxdr.c | 350 ++++++++++-----------
> fs/nfsd/xdr.h | 12 +-
> fs/nfsd/xdr3.h | 20 +-
> include/linux/nfsacl.h | 3 +
> include/linux/sunrpc/msg_prot.h | 3 -
> include/linux/sunrpc/xdr.h | 13 +-
> include/trace/events/sunrpc.h | 15 +-
> include/uapi/linux/nfs3.h | 6 +
> 15 files changed, 680 insertions(+), 615 deletions(-)
>
> --
> Chuck Lever