/* $NetBSD: pt_filter.c,v 1.13 2021/04/12 09:18:14 mrg Exp $ */ /* * Copyright (c) 1999 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD * Foundation by Brian Grayson, and is dedicated to Rebecca * Margaret Pollard-Grayson. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <sys/cdefs.h> #ifndef lint __RCSID("$NetBSD: pt_filter.c,v 1.13 2021/04/12 09:18:14 mrg Exp $"); #endif /* not lint */ #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <err.h> #include <sys/types.h> #include <sys/param.h> #include <sys/syslog.h> #include "portald.h" /* * Key will be <key><path>. We let the configuration file * tell us how to filter the file. */ #define FILTER_CMD_SIZE 8192 static void fill_cmd(char **, char *, char *, int); static void fill_cmd(char **cmdv, char *path, char *buff, int n) { int i; /* Make tempbuff at least as large as buff. */ char *tempbuff = malloc(n); if (tempbuff == NULL) err(1, NULL); strncpy(tempbuff, cmdv[0], n - 1); tempbuff[n - 1] = '\0'; for (i = 1; cmdv[i]; i++) { strncat(tempbuff, " ", n - strlen(tempbuff)); strncat(tempbuff, cmdv[i], n - strlen(tempbuff)); } strncat(tempbuff, " ", n - strlen(tempbuff)); /* Now do the snprintf into buff. */ snprintf(buff, n, tempbuff, path); free(tempbuff); } /* * Strip v[1], replace %s in v[2] v[3] ... with the remainder * of the path, and exec v[2] v[3] ... on the remainder. */ int portal_rfilter(struct portal_cred *pcr, char *key, char **v, int *fdp) { char cmd[FILTER_CMD_SIZE]; char *path; FILE *fp; int error = 0; char percent_s[] = "%s"; error = lose_credentials(pcr); if (error != 0) return error; #ifdef DEBUG fprintf(stderr, "rfilter: Got key %s\n", key); #endif if (!v[1] || !v[2]) { syslog(LOG_ERR, "rfilter: got strip-key of %s, and command start of %s\n", v[1], v[2]); exit(1); } /* * Format for rfilter in config file: * * matchkey rfilter stripkey cmd [arg1] [arg2] ... * any of arg1, arg2, etc. can have %s, in which case %s * will be replaced by the full path. If arg1 is * missing, %s is assumed, i.e. * bogus1 rfilter bogus1/ cmd1 * is equivalent to * bogus1 rfilter bogus1/ cmd1 %s */ /* * v[3] could be NULL, or could point to "". */ if (!v[3] || strlen(v[3]) == 0) v[3] = percent_s; /* Handle above assumption. */ path = key; /* Strip out stripkey if it matches leading part of key. */ if (!strncmp(v[1], key, strlen(v[1]))) path += strlen(v[1]); /* * v[0] is key match, v[1] says how much to strip, v[2] * is beginning of command proper. The first %s in v[2] * ... will be replaced with the path. */ fill_cmd(v + 2, path, cmd, FILTER_CMD_SIZE); if (strlen(cmd) >= FILTER_CMD_SIZE) { syslog(LOG_WARNING, "Warning: potential overflow on string! Length was %lu\n", (unsigned long)strlen(cmd)); return ENAMETOOLONG; } #ifdef DEBUG fprintf(stderr, "rfilter: Using cmd of %s\n", cmd); #endif fp = popen(cmd, "r"); if (fp == NULL) return errno; /* Before returning, restore original uid and gid. */ /* But only do this if we were root to start with. */ if (getuid() == 0) { if ((seteuid((uid_t) 0) < 0) || (setegid((gid_t) 0) < 0)) { error = errno; syslog(LOG_WARNING, "setcred: %m"); pclose(fp); fp = NULL; } } if (fp) fdp[0] = fileno(fp); return error; } int portal_wfilter(struct portal_cred *pcr, char *key, char **v, int *fdp) { char cmd[FILTER_CMD_SIZE]; char *path; FILE *fp; int error = 0; int cred_change_err = 0; cred_change_err = lose_credentials(pcr); if (cred_change_err != 0) return cred_change_err; path = key + (v[1] ? strlen(v[1]) : 0); /* * v[0] is key match, v[1] says how much to strip, v[2] * is beginning of command proper. */ fill_cmd(v + 2, path, cmd, FILTER_CMD_SIZE); if (strlen(cmd) >= FILTER_CMD_SIZE) { syslog(LOG_WARNING, "Warning: potential overflow on string! Length was %lu\n", (unsigned long)strlen(cmd)); return ENAMETOOLONG; } fp = popen(cmd, "w"); if (fp == NULL) { return errno; } /* Before returning, restore original uid and gid. */ /* But only do this if we were root to start with. */ if (getuid() == 0) { if ((seteuid((uid_t) 0) < 0) || (setegid((gid_t) 0) < 0)) { error = errno; syslog(LOG_WARNING, "setcred: %m"); pclose(fp); fp = NULL; } } if (fp) fdp[0] = fileno(fp); return error; }
