Imported from util-linux-2.2 tarball.

1 files changed, 95 insertions, 0 deletions

diff --git a/login-utils/newgrp.c b/login-utils/newgrp.c
new file mode 100644
index 000000000..ba13fdeb1
--- /dev/null
+++ b/login-utils/newgrp.c
@@ -0,0 +1,95 @@
+/* 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 */
+/* Currently maintained at ftp://ftp.daimi.aau.dk/pub/linux/poe/ */
+
+#include <unistd.h>
+#include <pwd.h>
+#include <grp.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include "pathnames.h"
+
+#ifndef TRUE
+# define TRUE 1
+#endif
+
+#ifndef FALSE
+# define FALSE 0
+#endif
+
+static int
+allow_setgid(struct passwd *pe, struct group *ge) 
+{
+    char **look;
+    int notfound = 1;
+	
+    if (getuid() == 0) return TRUE;	/* root may do anything */
+
+    look = ge->gr_mem;
+    while (*look && (notfound = strcmp(*look++,pe->pw_name)));
+
+    if(!notfound) return TRUE;		/* member of group => OK */
+
+    /* 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 */
+
+    if(ge->gr_passwd && ge->gr_passwd[0] != 0) {
+	if(strcmp(ge->gr_passwd, 
+		  crypt(getpass("Password: "), ge->gr_passwd)) == 0) {
+	    return TRUE;		/* password accepted */
+	}
+    }
+
+    return FALSE;			/* default to denial */
+}
+
+int 
+main(int argc, char *argv[])
+{
+    struct passwd *pw_entry;
+    struct group *gr_entry;
+    char *shell;
+    
+    if (!(pw_entry = getpwuid(getuid()))) {
+	perror("newgrp: Who are you?");
+	exit(1);
+    }
+    
+    shell = (pw_entry->pw_shell[0] ? pw_entry->pw_shell : _PATH_BSHELL);
+    
+    if (argc < 2) {
+	if(setgid(pw_entry->pw_gid) < 0) {
+	    perror("newgrp: setgid");
+	    exit(1);
+	}
+    } else {
+	if (!(gr_entry = getgrnam(argv[1]))) {
+	    perror("newgrp: No such group.");
+	    exit(1);
+	} else {
+	    if(allow_setgid(pw_entry, gr_entry)) {
+		if(setgid(gr_entry->gr_gid) < 0) {
+		    perror("newgrp: setgid");
+		    exit(1);
+		}
+	    } else {
+		puts("newgrp: Permission denied");
+		exit(1);
+	    }
+	}
+    }
+
+    if(setuid(getuid()) < 0) {
+	perror("newgrp: setuid");
+	exit(1);
+    }
+
+    fflush(stdout); fflush(stderr);
+    execl(shell,shell,(char*)0);
+    perror("No shell");
+    fflush(stderr);
+    exit(1);
+}