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/* $OpenBSD: skeyaudit.c,v 1.27 2016/04/02 14:37:42 krw Exp $ */ |
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/* |
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* Copyright (c) 1997, 2000, 2003 Todd C. Miller <Todd.Miller@courtesan.com> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL |
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* WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE |
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* FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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* |
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* Sponsored in part by the Defense Advanced Research Projects |
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* Agency (DARPA) and Air Force Research Laboratory, Air Force |
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* Materiel Command, USAF, under agreement number F39502-99-1-0512. |
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*/ |
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#include <sys/wait.h> |
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#include <err.h> |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <limits.h> |
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#include <login_cap.h> |
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#include <paths.h> |
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#include <pwd.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <unistd.h> |
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#include <skey.h> |
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void notify(struct passwd *, int, int); |
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void sanitise_stdfd(void); |
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FILE *runsendmail(struct passwd *, int *); |
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__dead void usage(void); |
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void |
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sanitise_stdfd(void) |
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{ |
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int nullfd, dupfd; |
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if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) { |
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fprintf(stderr, "Couldn't open /dev/null: %s\n", |
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strerror(errno)); |
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exit(1); |
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} |
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while (++dupfd <= STDERR_FILENO) { |
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/* Only populate closed fds. */ |
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if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) { |
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if (dup2(nullfd, dupfd) == -1) { |
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fprintf(stderr, "dup2: %s\n", strerror(errno)); |
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exit(1); |
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} |
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} |
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} |
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if (nullfd > STDERR_FILENO) |
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close(nullfd); |
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} |
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int |
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main(int argc, char **argv) |
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{ |
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struct passwd *pw; |
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struct skey key; |
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char *name; |
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int ch, left, aflag, iflag, limit; |
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if (pledge("stdio rpath wpath flock getpw proc exec id cpath", NULL) == -1) |
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err(1, "pledge"); |
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aflag = iflag = 0; |
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limit = 12; |
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while ((ch = getopt(argc, argv, "ail:")) != -1) |
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switch(ch) { |
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case 'a': |
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if (getuid() != 0) |
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errx(1, "only root may use the -a flag"); |
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aflag = 1; |
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break; |
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case 'i': |
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iflag = 1; |
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break; |
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case 'l': |
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errno = 0; |
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if ((limit = (int)strtol(optarg, NULL, 10)) == 0) |
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errno = ERANGE; |
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if (errno) { |
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warn("key limit"); |
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usage(); |
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} |
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break; |
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default: |
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usage(); |
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} |
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if (iflag) { |
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if (pledge("stdio rpath wpath flock getpw cpath", NULL) == -1) |
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err(1, "pledge"); |
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} |
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/* If we are in interactive mode, STDOUT_FILENO *must* be open. */ |
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if (iflag && fcntl(STDOUT_FILENO, F_GETFL) == -1 && errno == EBADF) |
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exit(1); |
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/* |
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* Make sure STDIN_FILENO, STDOUT_FILENO, and STDERR_FILENO are open. |
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* If not, open /dev/null in their place or bail. |
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*/ |
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sanitise_stdfd(); |
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if (argc - optind > 0) |
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usage(); |
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/* Need key.keyfile zero'd at the very least */ |
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(void)memset(&key, 0, sizeof(key)); |
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left = 0; |
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if (aflag) { |
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while ((ch = skeygetnext(&key)) == 0) { |
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left = key.n - 1; |
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if ((pw = getpwnam(key.logname)) == NULL) |
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continue; |
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if (left >= limit) |
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continue; |
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(void)fclose(key.keyfile); |
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key.keyfile = NULL; |
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notify(pw, left, iflag); |
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} |
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if (ch == -1) |
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errx(-1, "cannot open %s", _PATH_SKEYDIR); |
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} else { |
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if ((pw = getpwuid(getuid())) == NULL) |
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errx(1, "no passwd entry for uid %u", getuid()); |
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if ((name = strdup(pw->pw_name)) == NULL) |
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err(1, "cannot allocate memory"); |
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sevenbit(name); |
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switch (skeylookup(&key, name)) { |
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case 0: /* Success! */ |
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left = key.n - 1; |
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break; |
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case -1: /* File error */ |
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errx(1, "cannot open %s/%s", _PATH_SKEYDIR, |
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name); |
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break; |
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case 1: /* Unknown user */ |
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errx(1, "user %s is not listed in %s", name, |
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_PATH_SKEYDIR); |
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} |
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(void)fclose(key.keyfile); |
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if (left < limit) |
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notify(pw, left, iflag); |
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} |
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exit(0); |
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} |
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void |
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notify(struct passwd *pw, int seq, int interactive) |
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{ |
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static char hostname[HOST_NAME_MAX+1]; |
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pid_t pid; |
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FILE *out; |
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/* Only set this once */ |
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if (hostname[0] == '\0' && gethostname(hostname, sizeof(hostname)) == -1) |
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strlcpy(hostname, "unknown", sizeof(hostname)); |
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if (interactive) |
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out = stdout; |
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else |
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out = runsendmail(pw, &pid); |
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if (!interactive) |
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(void)fprintf(out, |
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"Auto-Submitted: auto-generated\n" |
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"To: %s\nSubject: IMPORTANT action required\n", pw->pw_name); |
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if (seq) |
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(void)fprintf(out, |
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"\nYou are nearing the end of your current S/Key sequence for account\n\ |
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%s on system %s.\n\n\ |
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Your S/Key sequence number is now %d. When it reaches zero\n\ |
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you will no longer be able to use S/Key to log into the system.\n\n", |
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pw->pw_name, hostname, seq); |
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else |
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(void)fprintf(out, |
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"\nYou are at the end of your current S/Key sequence for account\n\ |
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%s on system %s.\n\n\ |
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At this point you can no longer use S/Key to log into the system.\n\n", |
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pw->pw_name, hostname); |
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(void)fprintf(out, |
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"Type \"skeyinit -s\" to reinitialize your sequence number.\n\n"); |
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if (!interactive) { |
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(void)fclose(out); |
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(void)waitpid(pid, NULL, 0); |
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} |
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} |
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FILE * |
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runsendmail(struct passwd *pw, pid_t *pidp) |
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{ |
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FILE *fp; |
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int pfd[2]; |
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pid_t pid; |
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if (pipe(pfd) < 0) |
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return(NULL); |
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switch (pid = fork()) { |
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case -1: /* fork(2) failed */ |
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(void)close(pfd[0]); |
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(void)close(pfd[1]); |
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return(NULL); |
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case 0: /* In child */ |
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(void)close(pfd[1]); |
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(void)dup2(pfd[0], STDIN_FILENO); |
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(void)close(pfd[0]); |
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/* Run sendmail as target user not root */ |
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if (getuid() == 0 && |
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setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) { |
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warn("cannot set user context"); |
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_exit(127); |
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} |
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execl(_PATH_SENDMAIL, "sendmail", "-t", (char *)NULL); |
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warn("cannot run \"%s -t\"", _PATH_SENDMAIL); |
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_exit(127); |
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} |
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/* In parent */ |
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*pidp = pid; |
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fp = fdopen(pfd[1], "w"); |
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(void)close(pfd[0]); |
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return(fp); |
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} |
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__dead void |
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usage(void) |
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{ |
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extern char *__progname; |
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(void)fprintf(stderr, "usage: %s [-ai] [-l limit]\n", |
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__progname); |
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exit(1); |
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} |