setgid to group "write" so that terminals need not be world writable

SCCS-vsn: usr.bin/write/write.c 4.13

diff --git a/usr/src/usr.bin/write/write.c b/usr/src/usr.bin/write/write.c
index 32574d7..c0ddb19 100644 (file)
--- a/usr/src/usr.bin/write/write.c
+++ b/usr/src/usr.bin/write/write.c
@@ -1,5 +1,5 @@
 #ifndef        lint
 #ifndef        lint

-static char *sccsid = "@(#)write.c     4.12 %G%";
+static char *sccsid = "@(#)write.c     4.13 %G%";

 #endif
 /*
  * write to another user
 #endif
 /*
  * write to another user


@@ -70,7 +70,7 @@ main(argc, argv)
                perror("write: Can't stat your tty");
                exit(1);
        }
                perror("write: Can't stat your tty");
                exit(1);
        }

-       if ((stbuf.st_mode&02) == 0) {
+       if ((stbuf.st_mode&020) == 0) {

                fprintf(stderr,
                        "write: You have write permission turned off\n");
                if (!suser)
                fprintf(stderr,
                        "write: You have write permission turned off\n");
                if (!suser)


@@ -115,7 +115,7 @@ main(argc, argv)
                        if (histty[0]==0)
                                strcpy(histty, ttybuf);
                        if (access(ttybuf, 0) < 0 || stat(ttybuf, &stbuf) < 0 ||
                        if (histty[0]==0)
                                strcpy(histty, ttybuf);
                        if (access(ttybuf, 0) < 0 || stat(ttybuf, &stbuf) < 0 ||

-                           (stbuf.st_mode&02) == 0)
+                           (stbuf.st_mode&020) == 0)

                                nomesg++;
                        else {
                                strcpy(histty, ttybuf);
                                nomesg++;
                        else {
                                strcpy(histty, ttybuf);


@@ -223,6 +223,8 @@ ex(bp)
                goto out;
        }
        if (i == 0) {
                goto out;
        }
        if (i == 0) {

+               fclose(tf);             /* Close his terminal */
+               setgid(getgid());       /* Give up effective group privs */

                sigs((int (*)())0);
                execl(getenv("SHELL") ?
                    getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0);
                sigs((int (*)())0);
                execl(getenv("SHELL") ?
                    getenv("SHELL") : "/bin/sh", "sh", "-c", bp+1, 0);