The attached patch makes it possible to pass a session keyring through to the
process spawned by call_usermodehelper(). This allows patch 3/3 to pass an
authorisation key through to /sbin/request-key, thus permitting better access
controls when doing just-in-time key creation.

Signed-Off-By: David Howells <[EMAIL PROTECTED]>
---
warthog>diffstat -p1 keys-umhelper-2612rc1mm1.diff 
 arch/i386/mach-voyager/voyager_thread.c |    2 +-
 drivers/acpi/thermal.c                  |    2 +-
 drivers/input/input.c                   |    2 +-
 drivers/macintosh/therm_pm72.c          |    2 +-
 drivers/net/hamradio/baycom_epp.c       |    2 +-
 drivers/pnp/pnpbios/core.c              |    2 +-
 drivers/s390/crypto/z90main.c           |    2 +-
 include/linux/key.h                     |    8 ++++++++
 include/linux/kmod.h                    |    5 ++++-
 kernel/cpuset.c                         |    2 +-
 kernel/kmod.c                           |   15 ++++++++++++---
 lib/kobject_uevent.c                    |    2 +-
 security/keys/request_key.c             |    2 +-
 13 files changed, 34 insertions(+), 14 deletions(-)

diff -uNrp linux-2.6.12-rc1-mm1/arch/i386/mach-voyager/voyager_thread.c 
linux-2.6.12-rc1-mm1-keys-umhelper/arch/i386/mach-voyager/voyager_thread.c
--- linux-2.6.12-rc1-mm1/arch/i386/mach-voyager/voyager_thread.c        
2004-09-16 12:05:45.000000000 +0100
+++ linux-2.6.12-rc1-mm1-keys-umhelper/arch/i386/mach-voyager/voyager_thread.c  
2005-03-23 17:35:16.000000000 +0000
@@ -73,7 +73,7 @@ execute(const char *string)
                NULL,
        };
 
-       if ((ret = call_usermodehelper(argv[0], argv, envp, 1)) != 0) {
+       if ((ret = call_usermodehelper(argv[0], argv, envp, NULL, 1)) != 0) {
                printk(KERN_ERR "Voyager failed to run \"%s\": %i\n",
                       string, ret);
        }
diff -uNrp linux-2.6.12-rc1-mm1/drivers/acpi/thermal.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/acpi/thermal.c
--- linux-2.6.12-rc1-mm1/drivers/acpi/thermal.c 2005-03-23 17:22:24.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/acpi/thermal.c   2005-03-23 
17:35:16.000000000 +0000
@@ -441,7 +441,7 @@ acpi_thermal_call_usermode (
        envp[0] = "HOME=/";
        envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
        
-       call_usermodehelper(argv[0], argv, envp, 0);
+       call_usermodehelper(argv[0], argv, envp, NULL, 0);
 
        return_VALUE(0);
 }
diff -uNrp linux-2.6.12-rc1-mm1/drivers/input/input.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/input/input.c
--- linux-2.6.12-rc1-mm1/drivers/input/input.c  2005-03-23 17:22:27.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/input/input.c    2005-03-23 
17:35:16.000000000 +0000
@@ -415,7 +415,7 @@ static void input_call_hotplug(char *ver
                argv[0], argv[1], envp[0], envp[1], envp[2], envp[3], envp[4]);
 #endif
 
-       value = call_usermodehelper(argv [0], argv, envp, 0);
+       value = call_usermodehelper(argv [0], argv, envp, NULL, 0);
 
        kfree(buf);
        kfree(envp);
diff -uNrp linux-2.6.12-rc1-mm1/drivers/macintosh/therm_pm72.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/macintosh/therm_pm72.c
--- linux-2.6.12-rc1-mm1/drivers/macintosh/therm_pm72.c 2005-03-23 
17:22:28.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/macintosh/therm_pm72.c   
2005-03-23 17:35:16.000000000 +0000
@@ -1598,7 +1598,7 @@ static int call_critical_overtemp(void)
                                "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                                NULL };
 
-       return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
+       return call_usermodehelper(critical_overtemp_path, argv, envp, NULL, 0);
 }
 
 
diff -uNrp linux-2.6.12-rc1-mm1/drivers/net/hamradio/baycom_epp.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/net/hamradio/baycom_epp.c
--- linux-2.6.12-rc1-mm1/drivers/net/hamradio/baycom_epp.c      2005-03-23 
17:08:58.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/net/hamradio/baycom_epp.c        
2005-03-23 17:35:16.000000000 +0000
@@ -323,7 +323,7 @@ static int eppconfig(struct baycom_state
        sprintf(portarg, "%ld", bc->pdev->port->base);
        printk(KERN_DEBUG "%s: %s -s -p %s -m %s\n", bc_drvname, 
eppconfig_path, portarg, modearg);
 
-       return call_usermodehelper(eppconfig_path, argv, envp, 1);
+       return call_usermodehelper(eppconfig_path, argv, envp, NULL, 1);
 }
 
 /* ---------------------------------------------------------------------- */
diff -uNrp linux-2.6.12-rc1-mm1/drivers/pnp/pnpbios/core.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/pnp/pnpbios/core.c
--- linux-2.6.12-rc1-mm1/drivers/pnp/pnpbios/core.c     2005-03-23 
17:22:32.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/pnp/pnpbios/core.c       
2005-03-23 17:35:16.000000000 +0000
@@ -157,7 +157,7 @@ static int pnp_dock_event(int dock, stru
                info->location_id, info->serial, info->capabilities);
        envp[i] = NULL;
        
-       value = call_usermodehelper (argv [0], argv, envp, 0);
+       value = call_usermodehelper (argv [0], argv, envp, NULL, 0);
        kfree (buf);
        kfree (envp);
        return 0;
diff -uNrp linux-2.6.12-rc1-mm1/drivers/s390/crypto/z90main.c 
linux-2.6.12-rc1-mm1-keys-umhelper/drivers/s390/crypto/z90main.c
--- linux-2.6.12-rc1-mm1/drivers/s390/crypto/z90main.c  2005-03-23 
17:09:03.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/drivers/s390/crypto/z90main.c    
2005-03-23 17:35:16.000000000 +0000
@@ -3554,7 +3554,7 @@ z90crypt_hotplug_event(int dev_major, in
        envp[4] = minor;
        envp[5] = 0;
 
-       call_usermodehelper(argv[0], argv, envp, 0);
+       call_usermodehelper(argv[0], argv, envp, NULL, 0);
 #endif
 }
 #endif
diff -uNrp linux-2.6.12-rc1-mm1/include/linux/key.h 
linux-2.6.12-rc1-mm1-keys-umhelper/include/linux/key.h
--- linux-2.6.12-rc1-mm1/include/linux/key.h    2005-03-23 17:22:44.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/include/linux/key.h      2005-03-23 
17:35:16.000000000 +0000
@@ -273,6 +273,13 @@ extern void key_fsuid_changed(struct tas
 extern void key_fsgid_changed(struct task_struct *tsk);
 extern void key_init(void);
 
+#define __install_session_keyring(tsk, keyring)                        \
+({                                                             \
+       struct key *old_session = tsk->signal->session_keyring; \
+       tsk->signal->session_keyring = keyring;                 \
+       old_session;                                            \
+})
+
 #else /* CONFIG_KEYS */
 
 #define key_validate(k)                        0
@@ -281,6 +288,7 @@ extern void key_init(void);
 #define key_put(k)                     do { } while(0)
 #define alloc_uid_keyring(u)           0
 #define switch_uid_keyring(u)          do { } while(0)
+#define __install_session_keyring(t, k)        NULL
 #define copy_keys(f,t)                 0
 #define copy_thread_group_keys(t)      0
 #define exit_keys(t)                   do { } while(0)
diff -uNrp linux-2.6.12-rc1-mm1/include/linux/kmod.h 
linux-2.6.12-rc1-mm1-keys-umhelper/include/linux/kmod.h
--- linux-2.6.12-rc1-mm1/include/linux/kmod.h   2005-01-04 11:13:54.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/include/linux/kmod.h     2005-03-23 
17:35:16.000000000 +0000
@@ -34,7 +34,10 @@ static inline int request_module(const c
 #endif
 
 #define try_then_request_module(x, mod...) ((x) ?: (request_module(mod), (x)))
-extern int call_usermodehelper(char *path, char *argv[], char *envp[], int 
wait);
+
+struct key;
+extern int call_usermodehelper(char *path, char *argv[], char *envp[],
+                              struct key *session_keyring, int wait);
 extern void usermodehelper_init(void);
 
 #endif /* __LINUX_KMOD_H__ */
diff -uNrp linux-2.6.12-rc1-mm1/kernel/cpuset.c 
linux-2.6.12-rc1-mm1-keys-umhelper/kernel/cpuset.c
--- linux-2.6.12-rc1-mm1/kernel/cpuset.c        2005-03-23 17:22:44.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/kernel/cpuset.c  2005-03-23 
17:41:40.229194131 +0000
@@ -428,7 +428,7 @@ static int cpuset_release_agent(char *cp
        envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
        envp[i] = NULL;
 
-       return call_usermodehelper(argv[0], argv, envp, 0);
+       return call_usermodehelper(argv[0], argv, envp, NULL, 0);
 }
 
 /*
diff -uNrp linux-2.6.12-rc1-mm1/kernel/kmod.c 
linux-2.6.12-rc1-mm1-keys-umhelper/kernel/kmod.c
--- linux-2.6.12-rc1-mm1/kernel/kmod.c  2005-01-04 11:13:56.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/kernel/kmod.c    2005-03-23 
17:35:16.000000000 +0000
@@ -108,7 +108,7 @@ int request_module(const char *fmt, ...)
                return -ENOMEM;
        }
 
-       ret = call_usermodehelper(modprobe_path, argv, envp, 1);
+       ret = call_usermodehelper(modprobe_path, argv, envp, NULL, 1);
        atomic_dec(&kmod_concurrent);
        return ret;
 }
@@ -120,6 +120,7 @@ struct subprocess_info {
        char *path;
        char **argv;
        char **envp;
+       struct key *ring;
        int wait;
        int retval;
 };
@@ -130,16 +131,21 @@ struct subprocess_info {
 static int ____call_usermodehelper(void *data)
 {
        struct subprocess_info *sub_info = data;
+       struct key *old_session;
        int retval;
 
-       /* Unblock all signals. */
+       /* Unblock all signals and set the session keyring. */
+       key_get(sub_info->ring);
        flush_signals(current);
        spin_lock_irq(&current->sighand->siglock);
+       old_session = __install_session_keyring(current, sub_info->ring);
        flush_signal_handlers(current, 1);
        sigemptyset(&current->blocked);
        recalc_sigpending();
        spin_unlock_irq(&current->sighand->siglock);
 
+       key_put(old_session);
+
        /* We can run anywhere, unlike our parent keventd(). */
        set_cpus_allowed(current, CPU_MASK_ALL);
 
@@ -215,6 +221,7 @@ static void __call_usermodehelper(void *
  * @path: pathname for the application
  * @argv: null-terminated argument list
  * @envp: null-terminated environment list
+ * @session_keyring: session keyring for process (NULL for an empty keyring)
  * @wait: wait for the application to finish and return status.
  *
  * Runs a user-space application.  The application is started
@@ -224,7 +231,8 @@ static void __call_usermodehelper(void *
  * Must be called from process context.  Returns a negative error code
  * if program was not execed successfully, or 0.
  */
-int call_usermodehelper(char *path, char **argv, char **envp, int wait)
+int call_usermodehelper(char *path, char **argv, char **envp,
+                       struct key *session_keyring, int wait)
 {
        DECLARE_COMPLETION(done);
        struct subprocess_info sub_info = {
@@ -232,6 +240,7 @@ int call_usermodehelper(char *path, char
                .path           = path,
                .argv           = argv,
                .envp           = envp,
+               .ring           = session_keyring,
                .wait           = wait,
                .retval         = 0,
        };
diff -uNrp linux-2.6.12-rc1-mm1/lib/kobject_uevent.c 
linux-2.6.12-rc1-mm1-keys-umhelper/lib/kobject_uevent.c
--- linux-2.6.12-rc1-mm1/lib/kobject_uevent.c   2005-03-23 17:22:45.000000000 
+0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/lib/kobject_uevent.c     2005-03-23 
17:35:16.000000000 +0000
@@ -370,7 +370,7 @@ void kobject_hotplug(struct kobject *kob
        if (!hotplug_path[0])
                goto exit;
 
-       retval = call_usermodehelper (argv[0], argv, envp, 0);
+       retval = call_usermodehelper (argv[0], argv, envp, NULL, 0);
        if (retval)
                pr_debug ("%s - call_usermodehelper returned %d\n",
                          __FUNCTION__, retval);
diff -uNrp linux-2.6.12-rc1-mm1/security/keys/request_key.c 
linux-2.6.12-rc1-mm1-keys-umhelper/security/keys/request_key.c
--- linux-2.6.12-rc1-mm1/security/keys/request_key.c    2005-03-23 
17:22:46.000000000 +0000
+++ linux-2.6.12-rc1-mm1-keys-umhelper/security/keys/request_key.c      
2005-03-23 17:35:16.000000000 +0000
@@ -88,7 +88,7 @@ static int call_request_key(struct key *
        argv[i] = NULL;
 
        /* do it */
-       return call_usermodehelper(argv[0], argv, envp, 1);
+       return call_usermodehelper(argv[0], argv, envp, NULL, 1);
 
 } /* end call_request_key() */
 
-
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