![Ben Hutchings](/assets/img/avatar_default.png)
Use set_posix_acl, which includes proper permission checks, instead of calling ->set_acl directly. Without this anyone may be able to grant themselves permissions to a file by setting the ACL. Lock the inode to make the new checks atomic with respect to set_acl. (Also, nfsd was the only caller of set_acl not locking the inode, so I suspect this may fix other races.) This also simplifies the code, and ensures our ACLs are checked by posix_acl_valid. The permission checks and the inode locking were lost with commit4ac7249e
, which changed nfsd to use the set_acl inode operation directly instead of going through xattr handlers. Reported-by: David Sinquin <david@sinquin.eu> [agreunba@redhat.com: use set_posix_acl] Fixes:4ac7249e
Cc: Christoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
381 lines
8.9 KiB
C
381 lines
8.9 KiB
C
/*
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* Process version 2 NFSACL requests.
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*
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* Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de>
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*/
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#include "nfsd.h"
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/* FIXME: nfsacl.h is a broken header */
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#include <linux/nfsacl.h>
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#include <linux/gfp.h>
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#include "cache.h"
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#include "xdr3.h"
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#include "vfs.h"
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#define NFSDDBG_FACILITY NFSDDBG_PROC
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#define RETURN_STATUS(st) { resp->status = (st); return (st); }
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/*
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* NULL call.
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*/
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static __be32
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nfsacld_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
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{
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return nfs_ok;
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}
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/*
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* Get the Access and/or Default ACL of a file.
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*/
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static __be32 nfsacld_proc_getacl(struct svc_rqst * rqstp,
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struct nfsd3_getaclargs *argp, struct nfsd3_getaclres *resp)
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{
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struct posix_acl *acl;
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struct inode *inode;
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svc_fh *fh;
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__be32 nfserr = 0;
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dprintk("nfsd: GETACL(2acl) %s\n", SVCFH_fmt(&argp->fh));
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fh = fh_copy(&resp->fh, &argp->fh);
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nfserr = fh_verify(rqstp, &resp->fh, 0, NFSD_MAY_NOP);
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if (nfserr)
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RETURN_STATUS(nfserr);
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inode = d_inode(fh->fh_dentry);
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if (argp->mask & ~NFS_ACL_MASK)
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RETURN_STATUS(nfserr_inval);
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resp->mask = argp->mask;
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nfserr = fh_getattr(fh, &resp->stat);
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if (nfserr)
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RETURN_STATUS(nfserr);
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if (resp->mask & (NFS_ACL|NFS_ACLCNT)) {
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acl = get_acl(inode, ACL_TYPE_ACCESS);
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if (acl == NULL) {
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/* Solaris returns the inode's minimum ACL. */
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acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
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}
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if (IS_ERR(acl)) {
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nfserr = nfserrno(PTR_ERR(acl));
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goto fail;
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}
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resp->acl_access = acl;
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}
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if (resp->mask & (NFS_DFACL|NFS_DFACLCNT)) {
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/* Check how Solaris handles requests for the Default ACL
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of a non-directory! */
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acl = get_acl(inode, ACL_TYPE_DEFAULT);
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if (IS_ERR(acl)) {
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nfserr = nfserrno(PTR_ERR(acl));
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goto fail;
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}
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resp->acl_default = acl;
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}
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/* resp->acl_{access,default} are released in nfssvc_release_getacl. */
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RETURN_STATUS(0);
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fail:
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posix_acl_release(resp->acl_access);
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posix_acl_release(resp->acl_default);
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RETURN_STATUS(nfserr);
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}
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/*
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* Set the Access and/or Default ACL of a file.
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*/
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static __be32 nfsacld_proc_setacl(struct svc_rqst * rqstp,
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struct nfsd3_setaclargs *argp,
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struct nfsd_attrstat *resp)
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{
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struct inode *inode;
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svc_fh *fh;
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__be32 nfserr = 0;
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int error;
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dprintk("nfsd: SETACL(2acl) %s\n", SVCFH_fmt(&argp->fh));
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fh = fh_copy(&resp->fh, &argp->fh);
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nfserr = fh_verify(rqstp, &resp->fh, 0, NFSD_MAY_SATTR);
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if (nfserr)
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goto out;
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inode = d_inode(fh->fh_dentry);
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error = fh_want_write(fh);
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if (error)
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goto out_errno;
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fh_lock(fh);
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error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
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if (error)
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goto out_drop_lock;
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error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
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if (error)
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goto out_drop_lock;
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fh_unlock(fh);
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fh_drop_write(fh);
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nfserr = fh_getattr(fh, &resp->stat);
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out:
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/* argp->acl_{access,default} may have been allocated in
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nfssvc_decode_setaclargs. */
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posix_acl_release(argp->acl_access);
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posix_acl_release(argp->acl_default);
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return nfserr;
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out_drop_lock:
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fh_unlock(fh);
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fh_drop_write(fh);
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out_errno:
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nfserr = nfserrno(error);
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goto out;
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}
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/*
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* Check file attributes
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*/
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static __be32 nfsacld_proc_getattr(struct svc_rqst * rqstp,
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struct nfsd_fhandle *argp, struct nfsd_attrstat *resp)
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{
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__be32 nfserr;
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dprintk("nfsd: GETATTR %s\n", SVCFH_fmt(&argp->fh));
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fh_copy(&resp->fh, &argp->fh);
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nfserr = fh_verify(rqstp, &resp->fh, 0, NFSD_MAY_NOP);
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if (nfserr)
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return nfserr;
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nfserr = fh_getattr(&resp->fh, &resp->stat);
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return nfserr;
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}
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/*
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* Check file access
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*/
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static __be32 nfsacld_proc_access(struct svc_rqst *rqstp, struct nfsd3_accessargs *argp,
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struct nfsd3_accessres *resp)
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{
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__be32 nfserr;
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dprintk("nfsd: ACCESS(2acl) %s 0x%x\n",
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SVCFH_fmt(&argp->fh),
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argp->access);
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fh_copy(&resp->fh, &argp->fh);
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resp->access = argp->access;
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nfserr = nfsd_access(rqstp, &resp->fh, &resp->access, NULL);
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if (nfserr)
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return nfserr;
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nfserr = fh_getattr(&resp->fh, &resp->stat);
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return nfserr;
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}
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/*
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* XDR decode functions
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*/
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static int nfsaclsvc_decode_getaclargs(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_getaclargs *argp)
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{
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p = nfs2svc_decode_fh(p, &argp->fh);
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if (!p)
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return 0;
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argp->mask = ntohl(*p); p++;
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return xdr_argsize_check(rqstp, p);
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}
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static int nfsaclsvc_decode_setaclargs(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_setaclargs *argp)
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{
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struct kvec *head = rqstp->rq_arg.head;
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unsigned int base;
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int n;
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p = nfs2svc_decode_fh(p, &argp->fh);
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if (!p)
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return 0;
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argp->mask = ntohl(*p++);
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if (argp->mask & ~NFS_ACL_MASK ||
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!xdr_argsize_check(rqstp, p))
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return 0;
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base = (char *)p - (char *)head->iov_base;
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n = nfsacl_decode(&rqstp->rq_arg, base, NULL,
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(argp->mask & NFS_ACL) ?
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&argp->acl_access : NULL);
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if (n > 0)
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n = nfsacl_decode(&rqstp->rq_arg, base + n, NULL,
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(argp->mask & NFS_DFACL) ?
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&argp->acl_default : NULL);
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return (n > 0);
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}
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static int nfsaclsvc_decode_fhandleargs(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd_fhandle *argp)
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{
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p = nfs2svc_decode_fh(p, &argp->fh);
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if (!p)
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return 0;
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return xdr_argsize_check(rqstp, p);
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}
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static int nfsaclsvc_decode_accessargs(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_accessargs *argp)
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{
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p = nfs2svc_decode_fh(p, &argp->fh);
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if (!p)
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return 0;
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argp->access = ntohl(*p++);
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return xdr_argsize_check(rqstp, p);
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}
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/*
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* XDR encode functions
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*/
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/*
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* There must be an encoding function for void results so svc_process
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* will work properly.
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*/
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static int nfsaclsvc_encode_voidres(struct svc_rqst *rqstp, __be32 *p, void *dummy)
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{
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return xdr_ressize_check(rqstp, p);
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}
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/* GETACL */
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static int nfsaclsvc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_getaclres *resp)
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{
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struct dentry *dentry = resp->fh.fh_dentry;
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struct inode *inode;
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struct kvec *head = rqstp->rq_res.head;
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unsigned int base;
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int n;
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int w;
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/*
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* Since this is version 2, the check for nfserr in
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* nfsd_dispatch actually ensures the following cannot happen.
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* However, it seems fragile to depend on that.
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*/
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if (dentry == NULL || d_really_is_negative(dentry))
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return 0;
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inode = d_inode(dentry);
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p = nfs2svc_encode_fattr(rqstp, p, &resp->fh, &resp->stat);
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*p++ = htonl(resp->mask);
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if (!xdr_ressize_check(rqstp, p))
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return 0;
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base = (char *)p - (char *)head->iov_base;
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rqstp->rq_res.page_len = w = nfsacl_size(
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(resp->mask & NFS_ACL) ? resp->acl_access : NULL,
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(resp->mask & NFS_DFACL) ? resp->acl_default : NULL);
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while (w > 0) {
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if (!*(rqstp->rq_next_page++))
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return 0;
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w -= PAGE_SIZE;
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}
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n = nfsacl_encode(&rqstp->rq_res, base, inode,
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resp->acl_access,
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resp->mask & NFS_ACL, 0);
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if (n > 0)
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n = nfsacl_encode(&rqstp->rq_res, base + n, inode,
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resp->acl_default,
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resp->mask & NFS_DFACL,
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NFS_ACL_DEFAULT);
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return (n > 0);
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}
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static int nfsaclsvc_encode_attrstatres(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd_attrstat *resp)
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{
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p = nfs2svc_encode_fattr(rqstp, p, &resp->fh, &resp->stat);
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return xdr_ressize_check(rqstp, p);
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}
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/* ACCESS */
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static int nfsaclsvc_encode_accessres(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_accessres *resp)
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{
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p = nfs2svc_encode_fattr(rqstp, p, &resp->fh, &resp->stat);
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*p++ = htonl(resp->access);
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return xdr_ressize_check(rqstp, p);
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}
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/*
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* XDR release functions
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*/
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static int nfsaclsvc_release_getacl(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_getaclres *resp)
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{
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fh_put(&resp->fh);
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posix_acl_release(resp->acl_access);
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posix_acl_release(resp->acl_default);
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return 1;
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}
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static int nfsaclsvc_release_attrstat(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd_attrstat *resp)
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{
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fh_put(&resp->fh);
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return 1;
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}
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static int nfsaclsvc_release_access(struct svc_rqst *rqstp, __be32 *p,
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struct nfsd3_accessres *resp)
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{
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fh_put(&resp->fh);
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return 1;
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}
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#define nfsaclsvc_decode_voidargs NULL
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#define nfsaclsvc_release_void NULL
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#define nfsd3_fhandleargs nfsd_fhandle
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#define nfsd3_attrstatres nfsd_attrstat
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#define nfsd3_voidres nfsd3_voidargs
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struct nfsd3_voidargs { int dummy; };
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#define PROC(name, argt, rest, relt, cache, respsize) \
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{ (svc_procfunc) nfsacld_proc_##name, \
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(kxdrproc_t) nfsaclsvc_decode_##argt##args, \
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(kxdrproc_t) nfsaclsvc_encode_##rest##res, \
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(kxdrproc_t) nfsaclsvc_release_##relt, \
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sizeof(struct nfsd3_##argt##args), \
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sizeof(struct nfsd3_##rest##res), \
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0, \
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cache, \
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respsize, \
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}
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#define ST 1 /* status*/
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#define AT 21 /* attributes */
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#define pAT (1+AT) /* post attributes - conditional */
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#define ACL (1+NFS_ACL_MAX_ENTRIES*3) /* Access Control List */
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static struct svc_procedure nfsd_acl_procedures2[] = {
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PROC(null, void, void, void, RC_NOCACHE, ST),
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PROC(getacl, getacl, getacl, getacl, RC_NOCACHE, ST+1+2*(1+ACL)),
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PROC(setacl, setacl, attrstat, attrstat, RC_NOCACHE, ST+AT),
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PROC(getattr, fhandle, attrstat, attrstat, RC_NOCACHE, ST+AT),
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PROC(access, access, access, access, RC_NOCACHE, ST+AT+1),
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};
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struct svc_version nfsd_acl_version2 = {
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.vs_vers = 2,
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.vs_nproc = 5,
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.vs_proc = nfsd_acl_procedures2,
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.vs_dispatch = nfsd_dispatch,
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.vs_xdrsize = NFS3_SVC_XDRSIZE,
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.vs_hidden = 0,
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};
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