1 files changed, 34 insertions, 8 deletions

diff --git a/pty.c b/pty.c
index 40bfd5290..d05cb89a7 100644
--- a/pty.c
+++ b/pty.c
@@ -12,7 +12,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: pty.c,v 1.16 2000/09/07 21:13:37 markus Exp $");
+RCSID("$OpenBSD: pty.c,v 1.18 2000/12/13 06:36:05 deraadt Exp $");
 
 #ifdef HAVE_UTIL_H
 # include <util.h>
@@ -291,6 +291,7 @@ pty_setowner(struct passwd *pw, const char *ttyname)
         struct group *grp;
         gid_t gid;
         mode_t mode;
+        struct stat st;
 
         /* Determine the group to make the owner of the tty. */
         grp = getgrnam("tty");
@@ -302,11 +303,36 @@ pty_setowner(struct passwd *pw, const char *ttyname)
                 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
         }
 
-        /* Change ownership of the tty. */
-        if (chown(ttyname, pw->pw_uid, gid) < 0)
-                fatal("chown(%.100s, %d, %d) failed: %.100s",
-                    ttyname, pw->pw_uid, gid, strerror(errno));
-        if (chmod(ttyname, mode) < 0)
-                fatal("chmod(%.100s, 0%o) failed: %.100s",
-                    ttyname, mode, strerror(errno));
+        /*
+         * Change owner and mode of the tty as required.
+         * Warn but continue if filesystem is read-only and the uids match.
+         */
+        if (stat(ttyname, &st))
+                fatal("stat(%.100s) failed: %.100s", ttyname,
+                    strerror(errno));
+
+        if (st.st_uid != pw->pw_uid || st.st_gid != gid) {
+                if (chown(ttyname, pw->pw_uid, gid) < 0) {
+                        if (errno == EROFS && st.st_uid == pw->pw_uid)
+                                error("chown(%.100s, %d, %d) failed: %.100s",
+                                      ttyname, pw->pw_uid, gid, 
+                                      strerror(errno));
+                        else
+                                fatal("chown(%.100s, %d, %d) failed: %.100s",
+                                      ttyname, pw->pw_uid, gid, 
+                                      strerror(errno));
+                }
+        }
+
+        if ((st.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != mode) {
+                if (chmod(ttyname, mode) < 0) {
+                        if (errno == EROFS &&
+                            (st.st_mode & (S_IRGRP | S_IROTH)) == 0)
+                                error("chmod(%.100s, 0%o) failed: %.100s",
+                                      ttyname, mode, strerror(errno));
+                        else
+                                fatal("chmod(%.100s, 0%o) failed: %.100s",
+                                      ttyname, mode, strerror(errno));
+                }
+        }
 }