| 1 | /* $NetBSD: setmode.c,v 1.30 2003/08/07 16:42:56 agc Exp $ */
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| 2 |
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| 3 | /*
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| 4 | * Copyright (c) 1989, 1993, 1994
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| 5 | * The Regents of the University of California. All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to Berkeley by
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| 8 | * Dave Borman at Cray Research, Inc.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | * 3. Neither the name of the University nor the names of its contributors
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| 19 | * may be used to endorse or promote products derived from this software
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| 20 | * without specific prior written permission.
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| 21 | *
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| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 32 | * SUCH DAMAGE.
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| 33 | */
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| 34 |
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| 35 | #include <sys/cdefs.h>
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| 36 | #if defined(LIBC_SCCS) && !defined(lint)
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| 37 | #if 0
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| 38 | static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94";
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| 39 | #else
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| 40 | __RCSID("$NetBSD: setmode.c,v 1.30 2003/08/07 16:42:56 agc Exp $");
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| 41 | #endif
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| 42 | #endif /* LIBC_SCCS and not lint */
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| 43 |
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| 44 | #include "namespace.h"
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| 45 | #include <sys/types.h>
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| 46 | #include <sys/stat.h>
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| 47 |
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| 48 | #include <assert.h>
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| 49 | #include <ctype.h>
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| 50 | #include <errno.h>
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| 51 | #include <signal.h>
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| 52 | #include <stdlib.h>
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| 53 | #include <unistd.h>
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| 54 |
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| 55 | #ifdef SETMODE_DEBUG
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| 56 | #include <stdio.h>
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| 57 | #endif
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| 58 |
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| 59 | #ifdef __weak_alias
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| 60 | __weak_alias(getmode,_getmode)
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| 61 | __weak_alias(setmode,_setmode)
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| 62 | #endif
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| 63 |
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| 64 | #define SET_LEN 6 /* initial # of bitcmd struct to malloc */
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| 65 | #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */
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| 66 |
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| 67 | typedef struct bitcmd {
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| 68 | char cmd;
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| 69 | char cmd2;
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| 70 | mode_t bits;
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| 71 | } BITCMD;
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| 72 |
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| 73 | #define CMD2_CLR 0x01
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| 74 | #define CMD2_SET 0x02
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| 75 | #define CMD2_GBITS 0x04
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| 76 | #define CMD2_OBITS 0x08
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| 77 | #define CMD2_UBITS 0x10
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| 78 |
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| 79 | static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int));
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| 80 | static void compress_mode __P((BITCMD *));
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| 81 | #ifdef SETMODE_DEBUG
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| 82 | static void dumpmode __P((BITCMD *));
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| 83 | #endif
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| 84 |
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| 85 | /*
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| 86 | * Given the old mode and an array of bitcmd structures, apply the operations
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| 87 | * described in the bitcmd structures to the old mode, and return the new mode.
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| 88 | * Note that there is no '=' command; a strict assignment is just a '-' (clear
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| 89 | * bits) followed by a '+' (set bits).
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| 90 | */
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| 91 | mode_t
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| 92 | getmode(bbox, omode)
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| 93 | const void *bbox;
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| 94 | mode_t omode;
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| 95 | {
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| 96 | const BITCMD *set;
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| 97 | mode_t clrval, newmode, value;
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| 98 |
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| 99 | _DIAGASSERT(bbox != NULL);
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| 100 |
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| 101 | set = (const BITCMD *)bbox;
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| 102 | newmode = omode;
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| 103 | for (value = 0;; set++)
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| 104 | switch(set->cmd) {
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| 105 | /*
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| 106 | * When copying the user, group or other bits around, we "know"
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| 107 | * where the bits are in the mode so that we can do shifts to
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| 108 | * copy them around. If we don't use shifts, it gets real
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| 109 | * grundgy with lots of single bit checks and bit sets.
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| 110 | */
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| 111 | case 'u':
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| 112 | value = (newmode & S_IRWXU) >> 6;
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| 113 | goto common;
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| 114 |
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| 115 | case 'g':
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| 116 | value = (newmode & S_IRWXG) >> 3;
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| 117 | goto common;
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| 118 |
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| 119 | case 'o':
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| 120 | value = newmode & S_IRWXO;
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| 121 | common: if (set->cmd2 & CMD2_CLR) {
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| 122 | clrval =
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| 123 | (set->cmd2 & CMD2_SET) ? S_IRWXO : value;
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| 124 | if (set->cmd2 & CMD2_UBITS)
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| 125 | newmode &= ~((clrval<<6) & set->bits);
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| 126 | if (set->cmd2 & CMD2_GBITS)
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| 127 | newmode &= ~((clrval<<3) & set->bits);
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| 128 | if (set->cmd2 & CMD2_OBITS)
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| 129 | newmode &= ~(clrval & set->bits);
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| 130 | }
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| 131 | if (set->cmd2 & CMD2_SET) {
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| 132 | if (set->cmd2 & CMD2_UBITS)
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| 133 | newmode |= (value<<6) & set->bits;
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| 134 | if (set->cmd2 & CMD2_GBITS)
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| 135 | newmode |= (value<<3) & set->bits;
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| 136 | if (set->cmd2 & CMD2_OBITS)
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| 137 | newmode |= value & set->bits;
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| 138 | }
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| 139 | break;
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| 140 |
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| 141 | case '+':
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| 142 | newmode |= set->bits;
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| 143 | break;
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| 144 |
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| 145 | case '-':
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| 146 | newmode &= ~set->bits;
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| 147 | break;
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| 148 |
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| 149 | case 'X':
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| 150 | if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
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| 151 | newmode |= set->bits;
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| 152 | break;
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| 153 |
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| 154 | case '\0':
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| 155 | default:
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| 156 | #ifdef SETMODE_DEBUG
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| 157 | (void)printf("getmode:%04o -> %04o\n", omode, newmode);
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| 158 | #endif
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| 159 | return (newmode);
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| 160 | }
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| 161 | }
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| 162 |
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| 163 | #define ADDCMD(a, b, c, d) do { \
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| 164 | if (set >= endset) { \
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| 165 | BITCMD *newset; \
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| 166 | setlen += SET_LEN_INCR; \
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| 167 | newset = realloc(saveset, sizeof(BITCMD) * setlen); \
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| 168 | if (newset == NULL) { \
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| 169 | free(saveset); \
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| 170 | return (NULL); \
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| 171 | } \
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| 172 | set = newset + (set - saveset); \
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| 173 | saveset = newset; \
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| 174 | endset = newset + (setlen - 2); \
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| 175 | } \
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| 176 | set = addcmd(set, (a), (b), (c), (d)); \
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| 177 | } while (/*CONSTCOND*/0)
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| 178 |
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| 179 | #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
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| 180 |
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| 181 | void *
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| 182 | setmode(p)
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| 183 | const char *p;
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| 184 | {
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| 185 | int perm, who;
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| 186 | char op, *ep;
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| 187 | BITCMD *set, *saveset, *endset;
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| 188 | sigset_t signset, sigoset;
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| 189 | mode_t mask;
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| 190 | int equalopdone = 0; /* pacify gcc */
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| 191 | int permXbits, setlen;
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| 192 |
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| 193 | if (!*p)
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| 194 | return (NULL);
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| 195 |
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| 196 | /*
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| 197 | * Get a copy of the mask for the permissions that are mask relative.
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| 198 | * Flip the bits, we want what's not set. Since it's possible that
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| 199 | * the caller is opening files inside a signal handler, protect them
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| 200 | * as best we can.
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| 201 | */
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| 202 | sigfillset(&signset);
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| 203 | (void)sigprocmask(SIG_BLOCK, &signset, &sigoset);
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| 204 | (void)umask(mask = umask(0));
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| 205 | mask = ~mask;
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| 206 | (void)sigprocmask(SIG_SETMASK, &sigoset, NULL);
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| 207 |
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| 208 | setlen = SET_LEN + 2;
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| 209 |
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| 210 | if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
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| 211 | return (NULL);
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| 212 | saveset = set;
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| 213 | endset = set + (setlen - 2);
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| 214 |
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| 215 | /*
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| 216 | * If an absolute number, get it and return; disallow non-octal digits
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| 217 | * or illegal bits.
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| 218 | */
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| 219 | if (isdigit((unsigned char)*p)) {
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| 220 | perm = (mode_t)strtol(p, &ep, 8);
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| 221 | if (*ep || perm & ~(STANDARD_BITS|S_ISTXT)) {
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| 222 | free(saveset);
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| 223 | return (NULL);
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| 224 | }
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| 225 | ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
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| 226 | set->cmd = 0;
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| 227 | return (saveset);
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| 228 | }
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| 229 |
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| 230 | /*
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| 231 | * Build list of structures to set/clear/copy bits as described by
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| 232 | * each clause of the symbolic mode.
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| 233 | */
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| 234 | for (;;) {
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| 235 | /* First, find out which bits might be modified. */
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| 236 | for (who = 0;; ++p) {
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| 237 | switch (*p) {
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| 238 | case 'a':
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| 239 | who |= STANDARD_BITS;
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| 240 | break;
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| 241 | case 'u':
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| 242 | who |= S_ISUID|S_IRWXU;
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| 243 | break;
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| 244 | case 'g':
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| 245 | who |= S_ISGID|S_IRWXG;
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| 246 | break;
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| 247 | case 'o':
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| 248 | who |= S_IRWXO;
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| 249 | break;
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| 250 | default:
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| 251 | goto getop;
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| 252 | }
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| 253 | }
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| 254 |
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| 255 | getop: if ((op = *p++) != '+' && op != '-' && op != '=') {
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| 256 | free(saveset);
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| 257 | return (NULL);
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| 258 | }
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| 259 | if (op == '=')
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| 260 | equalopdone = 0;
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| 261 |
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| 262 | who &= ~S_ISTXT;
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| 263 | for (perm = 0, permXbits = 0;; ++p) {
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| 264 | switch (*p) {
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| 265 | case 'r':
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| 266 | perm |= S_IRUSR|S_IRGRP|S_IROTH;
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| 267 | break;
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| 268 | case 's':
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| 269 | /*
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| 270 | * If specific bits where requested and
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| 271 | * only "other" bits ignore set-id.
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| 272 | */
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| 273 | if (who == 0 || (who & ~S_IRWXO))
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| 274 | perm |= S_ISUID|S_ISGID;
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| 275 | break;
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| 276 | case 't':
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| 277 | /*
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| 278 | * If specific bits where requested and
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| 279 | * only "other" bits ignore set-id.
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| 280 | */
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| 281 | if (who == 0 || (who & ~S_IRWXO)) {
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| 282 | who |= S_ISTXT;
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| 283 | perm |= S_ISTXT;
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| 284 | }
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| 285 | break;
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| 286 | case 'w':
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| 287 | perm |= S_IWUSR|S_IWGRP|S_IWOTH;
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| 288 | break;
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| 289 | case 'X':
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| 290 | permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
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| 291 | break;
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| 292 | case 'x':
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| 293 | perm |= S_IXUSR|S_IXGRP|S_IXOTH;
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| 294 | break;
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| 295 | case 'u':
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| 296 | case 'g':
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| 297 | case 'o':
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| 298 | /*
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| 299 | * When ever we hit 'u', 'g', or 'o', we have
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| 300 | * to flush out any partial mode that we have,
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| 301 | * and then do the copying of the mode bits.
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| 302 | */
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| 303 | if (perm) {
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| 304 | ADDCMD(op, who, perm, mask);
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| 305 | perm = 0;
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| 306 | }
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| 307 | if (op == '=')
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| 308 | equalopdone = 1;
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| 309 | if (op == '+' && permXbits) {
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| 310 | ADDCMD('X', who, permXbits, mask);
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| 311 | permXbits = 0;
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| 312 | }
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| 313 | ADDCMD(*p, who, op, mask);
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| 314 | break;
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| 315 |
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| 316 | default:
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| 317 | /*
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| 318 | * Add any permissions that we haven't already
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| 319 | * done.
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| 320 | */
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| 321 | if (perm || (op == '=' && !equalopdone)) {
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| 322 | if (op == '=')
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| 323 | equalopdone = 1;
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| 324 | ADDCMD(op, who, perm, mask);
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| 325 | perm = 0;
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| 326 | }
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| 327 | if (permXbits) {
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| 328 | ADDCMD('X', who, permXbits, mask);
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| 329 | permXbits = 0;
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| 330 | }
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| 331 | goto apply;
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| 332 | }
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| 333 | }
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| 334 |
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| 335 | apply: if (!*p)
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| 336 | break;
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| 337 | if (*p != ',')
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| 338 | goto getop;
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| 339 | ++p;
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| 340 | }
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| 341 | set->cmd = 0;
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| 342 | #ifdef SETMODE_DEBUG
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| 343 | (void)printf("Before compress_mode()\n");
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| 344 | dumpmode(saveset);
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| 345 | #endif
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| 346 | compress_mode(saveset);
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| 347 | #ifdef SETMODE_DEBUG
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| 348 | (void)printf("After compress_mode()\n");
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| 349 | dumpmode(saveset);
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| 350 | #endif
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| 351 | return (saveset);
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| 352 | }
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| 353 |
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| 354 | static BITCMD *
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| 355 | addcmd(set, op, who, oparg, mask)
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| 356 | BITCMD *set;
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| 357 | int oparg, who;
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| 358 | int op;
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| 359 | u_int mask;
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| 360 | {
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| 361 |
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| 362 | _DIAGASSERT(set != NULL);
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| 363 |
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| 364 | switch (op) {
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| 365 | case '=':
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| 366 | set->cmd = '-';
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| 367 | set->bits = who ? who : STANDARD_BITS;
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| 368 | set++;
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| 369 |
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| 370 | op = '+';
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| 371 | /* FALLTHROUGH */
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| 372 | case '+':
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| 373 | case '-':
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| 374 | case 'X':
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| 375 | set->cmd = op;
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| 376 | set->bits = (who ? who : mask) & oparg;
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| 377 | break;
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| 378 |
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| 379 | case 'u':
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| 380 | case 'g':
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| 381 | case 'o':
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| 382 | set->cmd = op;
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| 383 | if (who) {
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| 384 | set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
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| 385 | ((who & S_IRGRP) ? CMD2_GBITS : 0) |
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| 386 | ((who & S_IROTH) ? CMD2_OBITS : 0);
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| 387 | set->bits = (mode_t)~0;
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| 388 | } else {
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| 389 | set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
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| 390 | set->bits = mask;
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| 391 | }
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| 392 |
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| 393 | if (oparg == '+')
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| 394 | set->cmd2 |= CMD2_SET;
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| 395 | else if (oparg == '-')
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| 396 | set->cmd2 |= CMD2_CLR;
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| 397 | else if (oparg == '=')
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| 398 | set->cmd2 |= CMD2_SET|CMD2_CLR;
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| 399 | break;
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| 400 | }
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| 401 | return (set + 1);
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| 402 | }
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| 403 |
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| 404 | #ifdef SETMODE_DEBUG
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| 405 | static void
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| 406 | dumpmode(set)
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| 407 | BITCMD *set;
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| 408 | {
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| 409 |
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| 410 | _DIAGASSERT(set != NULL);
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| 411 |
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| 412 | for (; set->cmd; ++set)
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| 413 | (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
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| 414 | set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
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| 415 | set->cmd2 & CMD2_CLR ? " CLR" : "",
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| 416 | set->cmd2 & CMD2_SET ? " SET" : "",
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| 417 | set->cmd2 & CMD2_UBITS ? " UBITS" : "",
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| 418 | set->cmd2 & CMD2_GBITS ? " GBITS" : "",
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| 419 | set->cmd2 & CMD2_OBITS ? " OBITS" : "");
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| 420 | }
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| 421 | #endif
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| 422 |
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| 423 | /*
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| 424 | * Given an array of bitcmd structures, compress by compacting consecutive
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| 425 | * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u',
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| 426 | * 'g' and 'o' commands continue to be separate. They could probably be
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| 427 | * compacted, but it's not worth the effort.
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| 428 | */
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| 429 | static void
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| 430 | compress_mode(set)
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| 431 | BITCMD *set;
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| 432 | {
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| 433 | BITCMD *nset;
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| 434 | int setbits, clrbits, Xbits, op;
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| 435 |
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| 436 | _DIAGASSERT(set != NULL);
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| 437 |
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| 438 | for (nset = set;;) {
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| 439 | /* Copy over any 'u', 'g' and 'o' commands. */
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| 440 | while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
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| 441 | *set++ = *nset++;
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| 442 | if (!op)
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| 443 | return;
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| 444 | }
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| 445 |
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| 446 | for (setbits = clrbits = Xbits = 0;; nset++) {
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| 447 | if ((op = nset->cmd) == '-') {
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| 448 | clrbits |= nset->bits;
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| 449 | setbits &= ~nset->bits;
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| 450 | Xbits &= ~nset->bits;
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| 451 | } else if (op == '+') {
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| 452 | setbits |= nset->bits;
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| 453 | clrbits &= ~nset->bits;
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| 454 | Xbits &= ~nset->bits;
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| 455 | } else if (op == 'X')
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| 456 | Xbits |= nset->bits & ~setbits;
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| 457 | else
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| 458 | break;
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|---|
| 459 | }
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| 460 | if (clrbits) {
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| 461 | set->cmd = '-';
|
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| 462 | set->cmd2 = 0;
|
|---|
| 463 | set->bits = clrbits;
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| 464 | set++;
|
|---|
| 465 | }
|
|---|
| 466 | if (setbits) {
|
|---|
| 467 | set->cmd = '+';
|
|---|
| 468 | set->cmd2 = 0;
|
|---|
| 469 | set->bits = setbits;
|
|---|
| 470 | set++;
|
|---|
| 471 | }
|
|---|
| 472 | if (Xbits) {
|
|---|
| 473 | set->cmd = 'X';
|
|---|
| 474 | set->cmd2 = 0;
|
|---|
| 475 | set->bits = Xbits;
|
|---|
| 476 | set++;
|
|---|
| 477 | }
|
|---|
| 478 | }
|
|---|
| 479 | }
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|---|
