1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * Portions of this source code were derived from Berkeley 4.3 BSD 31 * under license from the Regents of the University of California. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/isa_defs.h> 36 #include <sys/types.h> 37 #include <sys/sysmacros.h> 38 #include <sys/cred_impl.h> 39 #include <sys/systm.h> 40 #include <sys/errno.h> 41 #include <sys/pathname.h> 42 #include <sys/vnode.h> 43 #include <sys/uio.h> 44 #include <sys/cmn_err.h> 45 #include <sys/debug.h> 46 #include <sys/file.h> 47 #include <fs/fs_subr.h> 48 #include <c2/audit.h> 49 #include <sys/fcntl.h> 50 51 /* 52 * Determine accessibility of file. 53 */ 54 55 #define E_OK 010 /* use effective ids */ 56 #define R_OK 004 57 #define W_OK 002 58 #define X_OK 001 59 60 static int 61 caccess(char *fname, int fmode, vnode_t *startvp) 62 { 63 vnode_t *vp; 64 cred_t *tmpcr; 65 int error; 66 int mode; 67 int eok; 68 cred_t *cr; 69 int estale_retry = 0; 70 71 if (fmode & ~(E_OK|R_OK|W_OK|X_OK)) 72 return (set_errno(EINVAL)); 73 74 mode = ((fmode & (R_OK|W_OK|X_OK)) << 6); 75 76 cr = CRED(); 77 78 /* OK to use effective uid/gid, i.e., no need to crdup(CRED())? */ 79 eok = (fmode & E_OK) || 80 (cr->cr_uid == cr->cr_ruid && cr->cr_gid == cr->cr_rgid); 81 82 if (eok) 83 tmpcr = cr; 84 else { 85 tmpcr = crdup(cr); 86 tmpcr->cr_uid = cr->cr_ruid; 87 tmpcr->cr_gid = cr->cr_rgid; 88 tmpcr->cr_ruid = cr->cr_uid; 89 tmpcr->cr_rgid = cr->cr_gid; 90 } 91 92 lookup: 93 if (error = lookupnameatcred(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp, 94 startvp, tmpcr)) { 95 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 96 goto lookup; 97 if (!eok) 98 crfree(tmpcr); 99 return (set_errno(error)); 100 } 101 102 if (mode) { 103 error = VOP_ACCESS(vp, mode, 0, tmpcr, NULL); 104 if (error) { 105 if ((error == ESTALE) && 106 fs_need_estale_retry(estale_retry++)) { 107 VN_RELE(vp); 108 goto lookup; 109 } 110 (void) set_errno(error); 111 } 112 } 113 114 if (!eok) 115 crfree(tmpcr); 116 VN_RELE(vp); 117 return (error); 118 } 119 120 int 121 faccessat(int fd, char *fname, int fmode, int flag) 122 { 123 file_t *dirfp; 124 vnode_t *dirvp; 125 int error; 126 char startchar; 127 128 if (fd == AT_FDCWD && fname == NULL) 129 return (set_errno(EFAULT)); 130 131 if ((flag & ~AT_EACCESS) != 0) 132 return (set_errno(EINVAL)); 133 134 if (fname != NULL) { 135 if (copyin(fname, &startchar, sizeof (char))) 136 return (set_errno(EFAULT)); 137 } else 138 startchar = '\0'; 139 140 if (fd == AT_FDCWD) { 141 dirvp = NULL; 142 } else { 143 if (startchar != '/') { 144 if ((dirfp = getf(fd)) == NULL) { 145 return (set_errno(EBADF)); 146 } 147 dirvp = dirfp->f_vnode; 148 VN_HOLD(dirvp); 149 releasef(fd); 150 } else { 151 dirvp = NULL; 152 } 153 } 154 155 if (AU_AUDITING()) 156 audit_setfsat_path(1); 157 158 /* Do not allow E_OK unless AT_EACCESS flag is set */ 159 fmode &= ~E_OK; 160 if (flag & AT_EACCESS) 161 fmode |= E_OK; 162 163 error = caccess(fname, fmode, dirvp); 164 if (dirvp != NULL) 165 VN_RELE(dirvp); 166 167 return (error); 168 } 169 170 int 171 access(char *fname, int fmode) 172 { 173 return (faccessat(AT_FDCWD, fname, fmode, 0)); 174 } 175