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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-14 19:10:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-14 19:10:49 +0000
commitcfe5e3905201349e9cf3f95d52ff4bd100bde37d (patch)
treed0baf160cbee3195249d095f85e52d20c21acf02 /login-utils/newgrp.c
parentInitial commit. (diff)
downloadutil-linux-cfe5e3905201349e9cf3f95d52ff4bd100bde37d.tar.xz
util-linux-cfe5e3905201349e9cf3f95d52ff4bd100bde37d.zip
Adding upstream version 2.39.3.upstream/2.39.3
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'login-utils/newgrp.c')
-rw-r--r--login-utils/newgrp.c241
1 files changed, 241 insertions, 0 deletions
diff --git a/login-utils/newgrp.c b/login-utils/newgrp.c
new file mode 100644
index 0000000..2acbc91
--- /dev/null
+++ b/login-utils/newgrp.c
@@ -0,0 +1,241 @@
+/* setgrp.c - by Michael Haardt. Set the gid if possible
+ * Added a bit more error recovery/reporting - poe
+ * Vesa Roukonen added code for asking password */
+
+/* 1999-02-22 Arkadiusz Miƛkiewicz <misiek@pld.ORG.PL>
+ * - added Native Language Support
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+
+#ifdef HAVE_CRYPT_H
+# include <crypt.h>
+#endif
+
+#ifdef HAVE_GETSGNAM
+# include <gshadow.h>
+#endif
+
+#include "c.h"
+#include "closestream.h"
+#include "nls.h"
+#include "pathnames.h"
+#include "xalloc.h"
+
+static char *xgetpass(FILE *input, const char *prompt)
+{
+ char *pass = NULL;
+ struct termios saved, no_echo;
+ const int fd = fileno(input);
+ size_t dummy = 0;
+ ssize_t len;
+
+ fputs(prompt, stdout);
+ if (isatty(fd)) {
+ /* disable echo */
+ tcgetattr(fd, &saved);
+ no_echo = saved;
+ no_echo.c_lflag &= ~ECHO;
+ no_echo.c_lflag |= ECHONL;
+ if (tcsetattr(fd, TCSANOW, &no_echo))
+ err(EXIT_FAILURE, _("could not set terminal attributes"));
+ }
+ len = getline(&pass, &dummy, input);
+ if (isatty(fd))
+ /* restore terminal */
+ if (tcsetattr(fd, TCSANOW, &saved))
+ err(EXIT_FAILURE, _("could not set terminal attributes"));
+ if (len < 0)
+ err(EXIT_FAILURE, _("getline() failed"));
+ if (0 < len && *(pass + len - 1) == '\n')
+ *(pass + len - 1) = '\0';
+ return pass;
+}
+
+#ifndef HAVE_EXPLICIT_BZERO
+/* Ensure memory is set to value c without compiler optimization getting
+ * into way that could happen with memset(3). */
+static int xmemset_s(void *v, size_t sz, const int c)
+{
+ volatile unsigned char *p = v;
+
+ if (v == NULL)
+ return EINVAL;
+ while (sz--)
+ *p++ = c;
+ return 0;
+}
+#endif
+
+/* try to read password from gshadow */
+static char *get_gshadow_pwd(const char *groupname)
+{
+#ifdef HAVE_GETSGNAM
+ struct sgrp *sgrp;
+
+ sgrp = getsgnam(groupname);
+ return sgrp ? xstrdup(sgrp->sg_passwd) : NULL;
+#else
+ char buf[BUFSIZ];
+ char *pwd = NULL;
+ FILE *f;
+
+ if (groupname == NULL || *groupname == '\0')
+ return NULL;
+
+ f = fopen(_PATH_GSHADOW, "r");
+ if (!f)
+ return NULL;
+
+ while (fgets(buf, sizeof buf, f)) {
+ char *cp = strchr(buf, ':');
+ if (!cp)
+ /* any junk in gshadow? */
+ continue;
+ *cp = '\0';
+ if (strcmp(buf, groupname) == 0) {
+ if (cp - buf >= BUFSIZ)
+ /* only group name on line */
+ break;
+ pwd = cp + 1;
+ if ((cp = strchr(pwd, ':')) && pwd == cp + 1)
+ /* empty password */
+ pwd = NULL;
+ else if (cp)
+ *cp = '\0';
+ break;
+ }
+ }
+ fclose(f);
+ return pwd ? xstrdup(pwd) : NULL;
+#endif /* HAVE_GETSGNAM */
+}
+
+static int allow_setgid(const struct passwd *pe, const struct group *ge)
+{
+ char **look;
+ int notfound = 1;
+ char *pwd, *xpwd, *spwd;
+
+ if (getuid() == 0)
+ /* root may do anything */
+ return TRUE;
+ if (ge->gr_gid == pe->pw_gid)
+ /* You can switch back to your default group */
+ return TRUE;
+
+ look = ge->gr_mem;
+ while (*look && (notfound = strcmp(*look++, pe->pw_name))) ;
+
+ if (!notfound)
+ /* member of group => OK */
+ return TRUE;
+
+ /* Ask for password. Often there is no password in /etc/group, so
+ * contrary to login et al. we let an empty password mean the same
+ * as in /etc/passwd */
+
+ /* check /etc/gshadow */
+ spwd = get_gshadow_pwd(ge->gr_name);
+ pwd = spwd ? spwd : ge->gr_passwd;
+
+ if (pwd && *pwd && (xpwd = xgetpass(stdin, _("Password: ")))) {
+ char *cbuf = crypt(xpwd, pwd);
+
+#ifdef HAVE_EXPLICIT_BZERO
+ explicit_bzero(xpwd, strlen(xpwd));
+#else
+ xmemset_s(xpwd, strlen(xpwd), 0);
+#endif
+ free(xpwd);
+ if (!cbuf)
+ warn(_("crypt failed"));
+ else if (strcmp(pwd, cbuf) == 0)
+ return TRUE;
+ }
+
+ free(spwd);
+
+ /* default to denial */
+ return FALSE;
+}
+
+static void __attribute__((__noreturn__)) usage(void)
+{
+ FILE *out = stdout;
+ fputs(USAGE_HEADER, out);
+ fprintf(out, _(" %s <group>\n"), program_invocation_short_name);
+
+ fputs(USAGE_SEPARATOR, out);
+ fputs(_("Log in to a new group.\n"), out);
+
+ fputs(USAGE_OPTIONS, out);
+ printf(USAGE_HELP_OPTIONS(16));
+ printf(USAGE_MAN_TAIL("newgrp(1)"));
+ exit(EXIT_SUCCESS);
+}
+
+int main(int argc, char *argv[])
+{
+ struct passwd *pw_entry;
+ struct group *gr_entry;
+ char *shell;
+ int ch;
+ static const struct option longopts[] = {
+ {"version", no_argument, NULL, 'V'},
+ {"help", no_argument, NULL, 'h'},
+ {NULL, 0, NULL, 0}
+ };
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+ close_stdout_atexit();
+
+ while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
+ switch (ch) {
+ case 'V':
+ print_version(EXIT_SUCCESS);
+ case 'h':
+ usage();
+ default:
+ errtryhelp(EXIT_FAILURE);
+ }
+
+ if (!(pw_entry = getpwuid(getuid())))
+ err(EXIT_FAILURE, _("who are you?"));
+
+ if (argc < 2) {
+ if (setgid(pw_entry->pw_gid) < 0)
+ err(EXIT_FAILURE, _("setgid failed"));
+ } else {
+ errno = 0;
+ if (!(gr_entry = getgrnam(argv[1]))) {
+ if (errno)
+ err(EXIT_FAILURE, _("no such group"));
+ else
+ errx(EXIT_FAILURE, _("no such group"));
+ }
+ if (!allow_setgid(pw_entry, gr_entry))
+ errx(EXIT_FAILURE, _("permission denied"));
+ if (setgid(gr_entry->gr_gid) < 0)
+ err(EXIT_FAILURE, _("setgid failed"));
+ }
+
+ if (setuid(getuid()) < 0)
+ err(EXIT_FAILURE, _("setuid failed"));
+
+ fflush(NULL);
+ shell = (pw_entry->pw_shell && *pw_entry->pw_shell ?
+ pw_entry->pw_shell : _PATH_BSHELL);
+ execl(shell, shell, (char *)NULL);
+ errexec(shell);
+}