From 24d6db4b64a2335d85edced05776ba087ae86eef Mon Sep 17 00:00:00 2001
From: Thomas Schmitt <scdbackup@gmx.net>
Date: Wed, 26 Sep 2007 15:53:43 +0000
Subject: [PATCH] Disabled --allow_emulated_drives in setuid runs

---
 cdrskin/cdrskin.1           |  5 ++++-
 cdrskin/cdrskin.c           | 31 ++++++++++++++++++++++---------
 cdrskin/cdrskin_timestamp.h |  2 +-
 3 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/cdrskin/cdrskin.1 b/cdrskin/cdrskin.1
index 7944f5f..1e777ff 100644
--- a/cdrskin/cdrskin.1
+++ b/cdrskin/cdrskin.1
@@ -2,7 +2,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH CDRSKIN 1 "September 19, 2007"
+.TH CDRSKIN 1 "September 26, 2007"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -285,6 +285,9 @@ The target file address is given after prefix "stdio:".
 .br
 E.g.: dev=stdio:/tmp/my_pseudo_drive
 .br
+Note: --allow_emulated_drives will not work if cdrskin has changed user
+identity via the setuid bit of its access permissions.
+.br
 Warning: Superusers must take care not to spoil their hard disk via its raw
 block device (like /dev/hda or /dev/sd0).
 .br
diff --git a/cdrskin/cdrskin.c b/cdrskin/cdrskin.c
index a541b34..ca963f5 100644
--- a/cdrskin/cdrskin.c
+++ b/cdrskin/cdrskin.c
@@ -1946,6 +1946,16 @@ int Cdrpreskin_queue_msgs(struct CdrpreskiN *o, int flag)
 }
 
 
+int Cdrpreskin_consider_normal_user(int flag)
+{
+ fprintf(stderr,
+    "cdrskin: HINT : Consider to allow rw-access to the writer devices and\n");
+ fprintf(stderr,
+    "cdrskin: HINT : to run cdrskin under your normal user identity.\n");
+ return(1);
+}
+
+
 /* Start the fallback program as replacement of the cdrskin run.
    @param flag bit0=do not report start command
 */
@@ -1959,10 +1969,7 @@ int Cdrpreskin_fallback(struct CdrpreskiN *preskin, int argc, char **argv,
  if(getuid()!=geteuid() && !preskin->allow_setuid) {
    fprintf(stderr,
      "cdrskin: SORRY : uid and euid differ. Will not start external fallback program.\n");
-   fprintf(stderr,
-     "cdrskin: HINT : Consider to allow rw-access to the writer device and\n");
-   fprintf(stderr,
-     "cdrskin: HINT : to run cdrskin under your normal user identity.\n");
+   Cdrpreskin_consider_normal_user(0);
    fprintf(stderr,
     "cdrskin: HINT : Option  --allow_setuid  disables this safety check.\n");
    goto failure;
@@ -2213,7 +2220,12 @@ return:
      o->abort_handler= 3;
 
    } else if(strcmp(argv[i],"--allow_emulated_drives")==0) {
-     o->allow_emulated_drives= 1;
+     if(getuid()!=geteuid()) {
+       fprintf(stderr,
+   "cdrskin: SORRY : uid and euid differ. Will not --allow_emulated_drives\n");
+       Cdrpreskin_consider_normal_user(0);
+     } else
+       o->allow_emulated_drives= 1;
 
    } else if(strcmp(argv[i],"--allow_setuid")==0) {
      o->allow_setuid= 1;
@@ -6538,10 +6550,7 @@ sorry_failed_to_eject:;
  if(getuid()!=geteuid()) {
    fprintf(stderr,
      "cdrskin: SORRY : uid and euid differ. Will not start external eject.\n");
-   fprintf(stderr,
-     "cdrskin: HINT : Consider to allow rw-access to the writer device and\n");
-   fprintf(stderr,
-     "cdrskin: HINT : to run cdrskin under your normal user identity.\n");
+   Cdrpreskin_consider_normal_user(0);
    return(0);
  }
 
@@ -7534,6 +7543,10 @@ int Cdrskin_create(struct CdrskiN **o, struct CdrpreskiN **preskin,
        (*preskin)->demands_cdrskin_caps= 1;
      } else {
        fprintf(stderr,"cdrskin: SORRY : dev=stdio:... works only with option --allow_emulated_drives\n");
+       if(getuid()!=geteuid()) {
+         fprintf(stderr,"cdrskin: SORRY : but uid and euid differ. So this option will be rejected.\n");
+         Cdrpreskin_consider_normal_user(0);
+       }
        {*exit_value= 2; goto ex;}
      }
    }
diff --git a/cdrskin/cdrskin_timestamp.h b/cdrskin/cdrskin_timestamp.h
index 3243f99..4710fcf 100644
--- a/cdrskin/cdrskin_timestamp.h
+++ b/cdrskin/cdrskin_timestamp.h
@@ -1 +1 @@
-#define Cdrskin_timestamP "2007.09.24.181340"
+#define Cdrskin_timestamP "2007.09.26.155301"