xref: /illumos-gate/usr/src/uts/common/syscall/open.c (revision b02947bf393d39f68e6c7fa8ccb98688f7f9c407)
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 /*
23  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved	*/
28 
29 /*
30  * Copyright (c) 2013, OmniTI Computer Consulting, Inc. All rights reserved.
31  * Copyright 2021 OmniOS Community Edition (OmniOSce) Association.
32  */
33 /*
34  * Portions of this source code were derived from Berkeley 4.3 BSD
35  * under license from the Regents of the University of California.
36  */
37 
38 #include <sys/param.h>
39 #include <sys/isa_defs.h>
40 #include <sys/types.h>
41 #include <sys/sysmacros.h>
42 #include <sys/user.h>
43 #include <sys/systm.h>
44 #include <sys/errno.h>
45 #include <sys/fcntl.h>
46 #include <sys/stat.h>
47 #include <sys/vnode.h>
48 #include <sys/vfs.h>
49 #include <sys/file.h>
50 #include <sys/mode.h>
51 #include <sys/uio.h>
52 #include <sys/debug.h>
53 #include <c2/audit.h>
54 
55 /*
56  * Common code for openat().  Check permissions, allocate an open
57  * file structure, and call the device open routine (if any).
58  */
59 
60 static int
61 copen(int startfd, char *fname, int filemode, int createmode)
62 {
63 	struct pathname pn;
64 	vnode_t *vp, *sdvp;
65 	file_t *fp, *startfp;
66 	enum vtype type;
67 	int error;
68 	int fd, dupfd;
69 	vnode_t *startvp;
70 	proc_t *p = curproc;
71 	uio_seg_t seg = UIO_USERSPACE;
72 	char *open_filename = fname;
73 	uint32_t auditing = AU_AUDITING();
74 	char startchar;
75 
76 	if (filemode & (FSEARCH|FEXEC)) {
77 		/*
78 		 * Must be one or the other and neither FREAD nor FWRITE
79 		 * Must not be any of FAPPEND FCREAT FTRUNC FXATTR FXATTRDIROPEN
80 		 * XXX: Should these just be silently ignored?
81 		 */
82 		if ((filemode & (FREAD|FWRITE)) ||
83 		    (filemode & (FSEARCH|FEXEC)) == (FSEARCH|FEXEC) ||
84 		    (filemode & (FAPPEND|FCREAT|FTRUNC|FXATTR|FXATTRDIROPEN)))
85 			return (set_errno(EINVAL));
86 	}
87 
88 	if (startfd == AT_FDCWD) {
89 		/*
90 		 * Regular open()
91 		 */
92 		startvp = NULL;
93 	} else {
94 		/*
95 		 * We're here via openat()
96 		 */
97 		if (copyin(fname, &startchar, sizeof (char)))
98 			return (set_errno(EFAULT));
99 
100 		/*
101 		 * if startchar is / then startfd is ignored
102 		 */
103 		if (startchar == '/')
104 			startvp = NULL;
105 		else {
106 			if ((startfp = getf(startfd)) == NULL)
107 				return (set_errno(EBADF));
108 			startvp = startfp->f_vnode;
109 			VN_HOLD(startvp);
110 			releasef(startfd);
111 		}
112 	}
113 
114 	/*
115 	 * Handle __openattrdirat() requests
116 	 */
117 	if (filemode & FXATTRDIROPEN) {
118 		if (auditing && startvp != NULL)
119 			audit_setfsat_path(1);
120 		error = lookupnameat(fname, seg, FOLLOW, NULLVPP, &vp, startvp);
121 		if (startvp != NULL)
122 			VN_RELE(startvp);
123 		if (error != 0)
124 			return (set_errno(error));
125 
126 		startvp = vp;
127 	}
128 
129 	/*
130 	 * Do we need to go into extended attribute space?
131 	 */
132 	if (filemode & FXATTR) {
133 		if (startfd == AT_FDCWD) {
134 			if (copyin(fname, &startchar, sizeof (char)))
135 				return (set_errno(EFAULT));
136 
137 			/*
138 			 * If startchar == '/' then no extended attributes
139 			 * are looked up.
140 			 */
141 			if (startchar == '/') {
142 				startvp = NULL;
143 			} else {
144 				mutex_enter(&p->p_lock);
145 				startvp = PTOU(p)->u_cdir;
146 				VN_HOLD(startvp);
147 				mutex_exit(&p->p_lock);
148 			}
149 		}
150 
151 		/*
152 		 * Make sure we have a valid extended attribute request.
153 		 * We must either have a real fd or AT_FDCWD and a relative
154 		 * pathname.
155 		 */
156 		if (startvp == NULL) {
157 			goto noxattr;
158 		}
159 	}
160 
161 	if (filemode & (FXATTR|FXATTRDIROPEN)) {
162 		vattr_t vattr;
163 
164 		if (error = pn_get(fname, UIO_USERSPACE, &pn)) {
165 			goto out;
166 		}
167 
168 		/*
169 		 * In order to access hidden attribute directory the
170 		 * user must be able to stat() the file
171 		 */
172 		vattr.va_mask = AT_ALL;
173 		if (error = VOP_GETATTR(startvp, &vattr, 0, CRED(), NULL)) {
174 			pn_free(&pn);
175 			goto out;
176 		}
177 
178 		if ((startvp->v_vfsp->vfs_flag & VFS_XATTR) != 0 ||
179 		    vfs_has_feature(startvp->v_vfsp, VFSFT_SYSATTR_VIEWS)) {
180 			error = VOP_LOOKUP(startvp, "", &sdvp, &pn,
181 			    (filemode & FXATTRDIROPEN) ? LOOKUP_XATTR :
182 			    LOOKUP_XATTR|CREATE_XATTR_DIR, rootvp, CRED(),
183 			    NULL, NULL, NULL);
184 		} else {
185 			error = EINVAL;
186 		}
187 
188 		/*
189 		 * For __openattrdirat() use "." as filename to open
190 		 * as part of vn_openat()
191 		 */
192 		if (error == 0 && (filemode & FXATTRDIROPEN)) {
193 			open_filename = ".";
194 			seg = UIO_SYSSPACE;
195 		}
196 
197 		pn_free(&pn);
198 		if (error != 0)
199 			goto out;
200 
201 		VN_RELE(startvp);
202 		startvp = sdvp;
203 	}
204 
205 noxattr:
206 	if ((filemode & (FREAD|FWRITE|FSEARCH|FEXEC|FXATTRDIROPEN)) != 0) {
207 		if ((filemode & (FNONBLOCK|FNDELAY)) == (FNONBLOCK|FNDELAY))
208 			filemode &= ~FNDELAY;
209 		error = falloc((vnode_t *)NULL, filemode, &fp, &fd);
210 		if (error == 0) {
211 			if (auditing && startvp != NULL)
212 				audit_setfsat_path(1);
213 			/*
214 			 * Last arg is a don't-care term if
215 			 * !(filemode & FCREAT).
216 			 */
217 			error = vn_openat(open_filename, seg, filemode,
218 			    (int)(createmode & MODEMASK),
219 			    &vp, CRCREAT, PTOU(curproc)->u_cmask,
220 			    startvp, fd);
221 
222 			if (startvp != NULL)
223 				VN_RELE(startvp);
224 			if (error == 0) {
225 				if ((vp->v_flag & VDUP) == 0) {
226 					fp->f_vnode = vp;
227 					mutex_exit(&fp->f_tlock);
228 					/*
229 					 * We must now fill in the slot
230 					 * falloc reserved.
231 					 */
232 					setf(fd, fp);
233 					if ((filemode & FCLOEXEC) != 0) {
234 						f_setfd(fd, FD_CLOEXEC);
235 					}
236 					return (fd);
237 				} else {
238 					/*
239 					 * Special handling for /dev/fd.
240 					 * Give up the file pointer
241 					 * and dup the indicated file descriptor
242 					 * (in v_rdev). This is ugly, but I've
243 					 * seen worse.
244 					 */
245 					unfalloc(fp);
246 					dupfd = getminor(vp->v_rdev);
247 					type = vp->v_type;
248 					mutex_enter(&vp->v_lock);
249 					vp->v_flag &= ~VDUP;
250 					mutex_exit(&vp->v_lock);
251 					VN_RELE(vp);
252 					if (type != VCHR)
253 						return (set_errno(EINVAL));
254 					if ((fp = getf(dupfd)) == NULL) {
255 						setf(fd, NULL);
256 						return (set_errno(EBADF));
257 					}
258 					mutex_enter(&fp->f_tlock);
259 					fp->f_count++;
260 					mutex_exit(&fp->f_tlock);
261 					setf(fd, fp);
262 					if ((filemode & FCLOEXEC) != 0) {
263 						f_setfd(fd, FD_CLOEXEC);
264 					}
265 					releasef(dupfd);
266 				}
267 				return (fd);
268 			} else {
269 				setf(fd, NULL);
270 				unfalloc(fp);
271 				return (set_errno(error));
272 			}
273 		}
274 	} else {
275 		error = EINVAL;
276 	}
277 out:
278 	if (startvp != NULL)
279 		VN_RELE(startvp);
280 	return (set_errno(error));
281 }
282 
283 #define	OPENMODE32(fmode)	(((fmode) & (FSEARCH | FEXEC))? \
284 				    (fmode) : (fmode) - FOPEN)
285 #define	OPENMODE64(fmode)	(OPENMODE32(fmode) | FOFFMAX)
286 #ifdef _LP64
287 #define	OPENMODE(fmode)		OPENMODE64(fmode)
288 #else
289 #define	OPENMODE(fmode)		OPENMODE32(fmode)
290 #endif
291 
292 /*
293  * Open a file.
294  */
295 int
296 openat(int fd, char *path, int fmode, int cmode)
297 {
298 	return (copen(fd, path, OPENMODE(fmode), cmode));
299 }
300 
301 int
302 open(char *path, int fmode, int cmode)
303 {
304 	return (openat(AT_FDCWD, path, fmode, cmode));
305 }
306 
307 #if defined(_ILP32) || defined(_SYSCALL32_IMPL)
308 /*
309  * Open for large files in 32-bit environment. Sets the FOFFMAX flag.
310  */
311 int
312 openat64(int fd, char *path, int fmode, int cmode)
313 {
314 	return (copen(fd, path, OPENMODE64(fmode), cmode));
315 }
316 
317 int
318 open64(char *path, int fmode, int cmode)
319 {
320 	return (openat64(AT_FDCWD, path, fmode, cmode));
321 }
322 
323 #endif	/* _ILP32 || _SYSCALL32_IMPL */
324 
325 #ifdef _SYSCALL32_IMPL
326 /*
327  * Open for 32-bit compatibility on 64-bit kernel
328  */
329 int
330 openat32(int fd, char *path, int fmode, int cmode)
331 {
332 	return (copen(fd, path, OPENMODE32(fmode), cmode));
333 }
334 
335 int
336 open32(char *path, int fmode, int cmode)
337 {
338 	return (openat32(AT_FDCWD, path, fmode, cmode));
339 }
340 
341 #endif	/* _SYSCALL32_IMPL */
342