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![Jeff Layton](/assets/img/avatar_default.png)
lockd doesn't currently vet the start and length in nlm4 requests like it should, and can end up generating lock requests with arguments that overflow when passed to the filesystem. The NLM4 protocol uses unsigned 64-bit arguments for both start and length, whereas struct file_lock tracks the start and end as loff_t values. By the time we get around to calling nlm4svc_retrieve_args, we've lost the information that would allow us to determine if there was an overflow. Start tracking the actual start and len for NLM4 requests in the nlm_lock. In nlm4svc_retrieve_args, vet these values to ensure they won't cause an overflow, and return NLM4_FBIG if they do. Link: https://bugzilla.linux-nfs.org/show_bug.cgi?id=392 Reported-by: Jan Kasiak <j.kasiak@gmail.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: <stable@vger.kernel.org> # 5.14+
338 lines
7.3 KiB
C
338 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/lockd/xdr4.c
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*
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* XDR support for lockd and the lock client.
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*
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* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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* Copyright (C) 1999, Trond Myklebust <trond.myklebust@fys.uio.no>
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*/
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/nfs.h>
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#include <linux/sunrpc/xdr.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/sunrpc/stats.h>
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#include <linux/lockd/lockd.h>
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#include "svcxdr.h"
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static inline s64
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loff_t_to_s64(loff_t offset)
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{
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s64 res;
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if (offset > NLM4_OFFSET_MAX)
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res = NLM4_OFFSET_MAX;
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else if (offset < -NLM4_OFFSET_MAX)
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res = -NLM4_OFFSET_MAX;
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else
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res = offset;
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return res;
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}
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/*
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* NLM file handles are defined by specification to be a variable-length
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* XDR opaque no longer than 1024 bytes. However, this implementation
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* limits their length to the size of an NFSv3 file handle.
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*/
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static bool
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svcxdr_decode_fhandle(struct xdr_stream *xdr, struct nfs_fh *fh)
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{
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__be32 *p;
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u32 len;
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if (xdr_stream_decode_u32(xdr, &len) < 0)
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return false;
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if (len > NFS_MAXFHSIZE)
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return false;
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p = xdr_inline_decode(xdr, len);
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if (!p)
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return false;
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fh->size = len;
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memcpy(fh->data, p, len);
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memset(fh->data + len, 0, sizeof(fh->data) - len);
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return true;
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}
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static bool
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svcxdr_decode_lock(struct xdr_stream *xdr, struct nlm_lock *lock)
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{
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struct file_lock *fl = &lock->fl;
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if (!svcxdr_decode_string(xdr, &lock->caller, &lock->len))
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return false;
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if (!svcxdr_decode_fhandle(xdr, &lock->fh))
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return false;
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if (!svcxdr_decode_owner(xdr, &lock->oh))
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return false;
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if (xdr_stream_decode_u32(xdr, &lock->svid) < 0)
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return false;
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if (xdr_stream_decode_u64(xdr, &lock->lock_start) < 0)
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return false;
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if (xdr_stream_decode_u64(xdr, &lock->lock_len) < 0)
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return false;
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locks_init_lock(fl);
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fl->fl_flags = FL_POSIX;
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fl->fl_type = F_RDLCK;
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return true;
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}
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static bool
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svcxdr_encode_holder(struct xdr_stream *xdr, const struct nlm_lock *lock)
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{
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const struct file_lock *fl = &lock->fl;
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s64 start, len;
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/* exclusive */
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if (xdr_stream_encode_bool(xdr, fl->fl_type != F_RDLCK) < 0)
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return false;
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if (xdr_stream_encode_u32(xdr, lock->svid) < 0)
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return false;
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if (!svcxdr_encode_owner(xdr, &lock->oh))
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return false;
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start = loff_t_to_s64(fl->fl_start);
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if (fl->fl_end == OFFSET_MAX)
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len = 0;
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else
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len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1);
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if (xdr_stream_encode_u64(xdr, start) < 0)
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return false;
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if (xdr_stream_encode_u64(xdr, len) < 0)
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return false;
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return true;
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}
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static bool
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svcxdr_encode_testrply(struct xdr_stream *xdr, const struct nlm_res *resp)
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{
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if (!svcxdr_encode_stats(xdr, resp->status))
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return false;
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switch (resp->status) {
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case nlm_lck_denied:
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if (!svcxdr_encode_holder(xdr, &resp->lock))
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return false;
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}
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return true;
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}
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/*
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* Decode Call arguments
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*/
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bool
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nlm4svc_decode_void(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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return true;
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}
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bool
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nlm4svc_decode_testargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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u32 exclusive;
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if (!svcxdr_decode_cookie(xdr, &argp->cookie))
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return false;
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if (xdr_stream_decode_bool(xdr, &exclusive) < 0)
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return false;
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if (!svcxdr_decode_lock(xdr, &argp->lock))
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return false;
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if (exclusive)
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argp->lock.fl.fl_type = F_WRLCK;
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return true;
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}
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bool
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nlm4svc_decode_lockargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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u32 exclusive;
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if (!svcxdr_decode_cookie(xdr, &argp->cookie))
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return false;
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if (xdr_stream_decode_bool(xdr, &argp->block) < 0)
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return false;
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if (xdr_stream_decode_bool(xdr, &exclusive) < 0)
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return false;
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if (!svcxdr_decode_lock(xdr, &argp->lock))
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return false;
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if (exclusive)
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argp->lock.fl.fl_type = F_WRLCK;
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if (xdr_stream_decode_bool(xdr, &argp->reclaim) < 0)
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return false;
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if (xdr_stream_decode_u32(xdr, &argp->state) < 0)
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return false;
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argp->monitor = 1; /* monitor client by default */
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return true;
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}
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bool
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nlm4svc_decode_cancargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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u32 exclusive;
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if (!svcxdr_decode_cookie(xdr, &argp->cookie))
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return false;
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if (xdr_stream_decode_bool(xdr, &argp->block) < 0)
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return false;
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if (xdr_stream_decode_bool(xdr, &exclusive) < 0)
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return false;
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if (!svcxdr_decode_lock(xdr, &argp->lock))
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return false;
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if (exclusive)
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argp->lock.fl.fl_type = F_WRLCK;
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return true;
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}
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bool
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nlm4svc_decode_unlockargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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if (!svcxdr_decode_cookie(xdr, &argp->cookie))
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return false;
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if (!svcxdr_decode_lock(xdr, &argp->lock))
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return false;
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argp->lock.fl.fl_type = F_UNLCK;
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return true;
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}
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bool
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nlm4svc_decode_res(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_res *resp = rqstp->rq_argp;
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if (!svcxdr_decode_cookie(xdr, &resp->cookie))
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return false;
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if (!svcxdr_decode_stats(xdr, &resp->status))
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return false;
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return true;
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}
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bool
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nlm4svc_decode_reboot(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_reboot *argp = rqstp->rq_argp;
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__be32 *p;
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u32 len;
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if (xdr_stream_decode_u32(xdr, &len) < 0)
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return false;
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if (len > SM_MAXSTRLEN)
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return false;
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p = xdr_inline_decode(xdr, len);
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if (!p)
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return false;
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argp->len = len;
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argp->mon = (char *)p;
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if (xdr_stream_decode_u32(xdr, &argp->state) < 0)
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return false;
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p = xdr_inline_decode(xdr, SM_PRIV_SIZE);
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if (!p)
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return false;
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memcpy(&argp->priv.data, p, sizeof(argp->priv.data));
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return true;
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}
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bool
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nlm4svc_decode_shareargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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struct nlm_lock *lock = &argp->lock;
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memset(lock, 0, sizeof(*lock));
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locks_init_lock(&lock->fl);
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lock->svid = ~(u32)0;
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if (!svcxdr_decode_cookie(xdr, &argp->cookie))
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return false;
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if (!svcxdr_decode_string(xdr, &lock->caller, &lock->len))
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return false;
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if (!svcxdr_decode_fhandle(xdr, &lock->fh))
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return false;
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if (!svcxdr_decode_owner(xdr, &lock->oh))
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return false;
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/* XXX: Range checks are missing in the original code */
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if (xdr_stream_decode_u32(xdr, &argp->fsm_mode) < 0)
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return false;
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if (xdr_stream_decode_u32(xdr, &argp->fsm_access) < 0)
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return false;
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return true;
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}
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bool
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nlm4svc_decode_notify(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_args *argp = rqstp->rq_argp;
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struct nlm_lock *lock = &argp->lock;
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if (!svcxdr_decode_string(xdr, &lock->caller, &lock->len))
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return false;
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if (xdr_stream_decode_u32(xdr, &argp->state) < 0)
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return false;
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return true;
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}
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/*
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* Encode Reply results
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*/
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bool
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nlm4svc_encode_void(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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return true;
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}
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bool
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nlm4svc_encode_testres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_res *resp = rqstp->rq_resp;
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return svcxdr_encode_cookie(xdr, &resp->cookie) &&
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svcxdr_encode_testrply(xdr, resp);
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}
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bool
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nlm4svc_encode_res(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_res *resp = rqstp->rq_resp;
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return svcxdr_encode_cookie(xdr, &resp->cookie) &&
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svcxdr_encode_stats(xdr, resp->status);
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}
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bool
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nlm4svc_encode_shareres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
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{
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struct nlm_res *resp = rqstp->rq_resp;
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if (!svcxdr_encode_cookie(xdr, &resp->cookie))
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return false;
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if (!svcxdr_encode_stats(xdr, resp->status))
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return false;
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/* sequence */
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if (xdr_stream_encode_u32(xdr, 0) < 0)
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return false;
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return true;
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}
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