// SPDX-License-Identifier: GPL-2.0 #include <linux/fs.h> #include <linux/gfp.h> #include <linux/nfs.h> #include <linux/nfs3.h> #include <linux/nfs_fs.h> #include <linux/posix_acl_xattr.h> #include <linux/nfsacl.h> #include "internal.h" #include "nfs3_fs.h" #define NFSDBG_FACILITY NFSDBG_PROC /* * nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for * caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl() * for explanations. */ static void nfs3_prepare_get_acl(struct posix_acl **p) { struct posix_acl *sentinel = uncached_acl_sentinel(current); if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) { /* Not the first reader or sentinel already in place. */ } } static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl) { struct posix_acl *sentinel = uncached_acl_sentinel(current); /* Only cache the ACL if our sentinel is still in place. */ posix_acl_dup(acl); if (cmpxchg(p, sentinel, acl) != sentinel) posix_acl_release(acl); } static void nfs3_abort_get_acl(struct posix_acl **p) { struct posix_acl *sentinel = uncached_acl_sentinel(current); /* Remove our sentinel upon failure. */ cmpxchg(p, sentinel, ACL_NOT_CACHED); } struct posix_acl *nfs3_get_acl(struct inode *inode, int type) { struct nfs_server *server = NFS_SERVER(inode); struct page *pages[NFSACL_MAXPAGES] = { }; struct nfs3_getaclargs args = { .fh = NFS_FH(inode), /* The xdr layer may allocate pages here. */ .pages = pages, }; struct nfs3_getaclres res = { NULL, }; struct rpc_message msg = { .rpc_argp = &args, .rpc_resp = &res, }; int status, count; if (!nfs_server_capable(inode, NFS_CAP_ACLS)) return ERR_PTR(-EOPNOTSUPP); status = nfs_revalidate_inode(server, inode); if (status < 0) return ERR_PTR(status); /* * Only get the access acl when explicitly requested: We don't * need it for access decisions, and only some applications use * it. Applications which request the access acl first are not * penalized from this optimization. */ if (type == ACL_TYPE_ACCESS) args.mask |= NFS_ACLCNT|NFS_ACL; if (S_ISDIR(inode->i_mode)) args.mask |= NFS_DFACLCNT|NFS_DFACL; if (args.mask == 0) return NULL; dprintk("NFS call getacl\n"); msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL]; res.fattr = nfs_alloc_fattr(); if (res.fattr == NULL) return ERR_PTR(-ENOMEM); if (args.mask & NFS_ACL) nfs3_prepare_get_acl(&inode->i_acl); if (args.mask & NFS_DFACL) nfs3_prepare_get_acl(&inode->i_default_acl); status = rpc_call_sync(server->client_acl, &msg, 0); dprintk("NFS reply getacl: %d\n", status); /* pages may have been allocated at the xdr layer. */ for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++) __free_page(args.pages[count]); switch (status) { case 0: status = nfs_refresh_inode(inode, res.fattr); break; case -EPFNOSUPPORT: case -EPROTONOSUPPORT: dprintk("NFS_V3_ACL extension not supported; disabling\n"); server->caps &= ~NFS_CAP_ACLS; fallthrough; case -ENOTSUPP: status = -EOPNOTSUPP; default: goto getout; } if ((args.mask & res.mask) != args.mask) { status = -EIO; goto getout; } if (res.acl_access != NULL) { if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) || res.acl_access->a_count == 0) { posix_acl_release(res.acl_access); res.acl_access = NULL; } } if (res.mask & NFS_ACL) nfs3_complete_get_acl(&inode->i_acl, res.acl_access); else forget_cached_acl(inode, ACL_TYPE_ACCESS); if (res.mask & NFS_DFACL) nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default); else forget_cached_acl(inode, ACL_TYPE_DEFAULT); nfs_free_fattr(res.fattr); if (type == ACL_TYPE_ACCESS) { posix_acl_release(res.acl_default); return res.acl_access; } else { posix_acl_release(res.acl_access); return res.acl_default; } getout: nfs3_abort_get_acl(&inode->i_acl); nfs3_abort_get_acl(&inode->i_default_acl); posix_acl_release(res.acl_access); posix_acl_release(res.acl_default); nfs_free_fattr(res.fattr); return ERR_PTR(status); } static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, struct posix_acl *dfacl) { struct nfs_server *server = NFS_SERVER(inode); struct nfs_fattr *fattr; struct page *pages[NFSACL_MAXPAGES]; struct nfs3_setaclargs args = { .inode = inode, .mask = NFS_ACL, .acl_access = acl, .pages = pages, }; struct rpc_message msg = { .rpc_argp = &args, .rpc_resp = &fattr, }; int status = 0; if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL)) goto out; status = -EOPNOTSUPP; if (!nfs_server_capable(inode, NFS_CAP_ACLS)) goto out; /* We are doing this here because XDR marshalling does not * return any results, it BUGs. */ status = -ENOSPC; if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES) goto out; if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES) goto out; if (S_ISDIR(inode->i_mode)) { args.mask |= NFS_DFACL; args.acl_default = dfacl; args.len = nfsacl_size(acl, dfacl); } else args.len = nfsacl_size(acl, NULL); if (args.len > NFS_ACL_INLINE_BUFSIZE) { unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT); status = -ENOMEM; do { args.pages[args.npages] = alloc_page(GFP_KERNEL); if (args.pages[args.npages] == NULL) goto out_freepages; args.npages++; } while (args.npages < npages); } dprintk("NFS call setacl\n"); status = -ENOMEM; fattr = nfs_alloc_fattr(); if (fattr == NULL) goto out_freepages; msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL]; msg.rpc_resp = fattr; status = rpc_call_sync(server->client_acl, &msg, 0); nfs_access_zap_cache(inode); nfs_zap_acl_cache(inode); dprintk("NFS reply setacl: %d\n", status); switch (status) { case 0: status = nfs_refresh_inode(inode, fattr); break; case -EPFNOSUPPORT: case -EPROTONOSUPPORT: dprintk("NFS_V3_ACL SETACL RPC not supported" "(will not retry)\n"); server->caps &= ~NFS_CAP_ACLS; fallthrough; case -ENOTSUPP: status = -EOPNOTSUPP; } nfs_free_fattr(fattr); out_freepages: while (args.npages != 0) { args.npages--; __free_page(args.pages[args.npages]); } out: return status; } int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl, struct posix_acl *dfacl) { int ret; ret = __nfs3_proc_setacls(inode, acl, dfacl); return (ret == -EOPNOTSUPP) ? 0 : ret; } int nfs3_set_acl(struct inode *inode, struct posix_acl *acl, int type) { struct posix_acl *orig = acl, *dfacl = NULL, *alloc; int status; if (S_ISDIR(inode->i_mode)) { switch(type) { case ACL_TYPE_ACCESS: alloc = get_acl(inode, ACL_TYPE_DEFAULT); if (IS_ERR(alloc)) goto fail; dfacl = alloc; break; case ACL_TYPE_DEFAULT: alloc = get_acl(inode, ACL_TYPE_ACCESS); if (IS_ERR(alloc)) goto fail; dfacl = acl; acl = alloc; break; } } if (acl == NULL) { alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL); if (IS_ERR(alloc)) goto fail; acl = alloc; } status = __nfs3_proc_setacls(inode, acl, dfacl); out: if (acl != orig) posix_acl_release(acl); if (dfacl != orig) posix_acl_release(dfacl); return status; fail: status = PTR_ERR(alloc); goto out; } const struct xattr_handler *nfs3_xattr_handlers[] = { &posix_acl_access_xattr_handler, &posix_acl_default_xattr_handler, NULL, }; static int nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data, size_t size, ssize_t *result) { struct posix_acl *acl; char *p = data + *result; acl = get_acl(inode, type); if (IS_ERR_OR_NULL(acl)) return 0; posix_acl_release(acl); *result += strlen(name); *result += 1; if (!size) return 0; if (*result > size) return -ERANGE; strcpy(p, name); return 0; } ssize_t nfs3_listxattr(struct dentry *dentry, char *data, size_t size) { struct inode *inode = d_inode(dentry); ssize_t result = 0; int error; error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS, XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result); if (error) return error; error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT, XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result); if (error) return error; return result; }