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authorDavid Howells <dhowells@redhat.com>2005-06-23 22:00:51 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-24 00:05:18 -0700
commit7888e7ff4ee579442128d7d12a9c9dbf2cf7de6a (patch)
treeabe428ecb966e1dae07fce17f38e3e0c0ab4f134
parent76d8aeabfeb1c42641a81c44280177b9a08670d8 (diff)
downloadlinux-linaro-stable-7888e7ff4ee579442128d7d12a9c9dbf2cf7de6a.tar.gz
[PATCH] Keys: Pass session keyring to call_usermodehelper()
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 <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/key.h10
-rw-r--r--include/linux/kmod.h13
-rw-r--r--kernel/kmod.c17
-rw-r--r--security/keys/request_key.c2
4 files changed, 35 insertions, 7 deletions
diff --git a/include/linux/key.h b/include/linux/key.h
index 2c24ffaca86f..2bfbf88d2740 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -273,14 +273,22 @@ extern void key_fsuid_changed(struct task_struct *tsk);
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
#define key_serial(k) 0
-#define key_get(k) NULL
+#define key_get(k) ({ NULL; })
#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 --git a/include/linux/kmod.h b/include/linux/kmod.h
index 95d0e4b0814d..e4a231549407 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -19,6 +19,7 @@
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
+#include <linux/stddef.h>
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/compiler.h>
@@ -34,7 +35,17 @@ static inline int request_module(const char * name, ...) { return -ENOSYS; }
#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_keys(char *path, char *argv[], char *envp[],
+ struct key *session_keyring, int wait);
+
+static inline int
+call_usermodehelper(char *path, char **argv, char **envp, int wait)
+{
+ return call_usermodehelper_keys(path, argv, envp, NULL, wait);
+}
+
extern void usermodehelper_init(void);
#endif /* __LINUX_KMOD_H__ */
diff --git a/kernel/kmod.c b/kernel/kmod.c
index eed53d4f5230..44166e3bb8af 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -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);
@@ -211,10 +217,11 @@ static void __call_usermodehelper(void *data)
}
/**
- * call_usermodehelper - start a usermode application
+ * call_usermodehelper_keys - start a usermode application
* @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 *data)
* 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_keys(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 **argv, char **envp, int wait)
.path = path,
.argv = argv,
.envp = envp,
+ .ring = session_keyring,
.wait = wait,
.retval = 0,
};
@@ -247,7 +256,7 @@ int call_usermodehelper(char *path, char **argv, char **envp, int wait)
wait_for_completion(&done);
return sub_info.retval;
}
-EXPORT_SYMBOL(call_usermodehelper);
+EXPORT_SYMBOL(call_usermodehelper_keys);
void __init usermodehelper_init(void)
{
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 1f6c0940297f..1919540f047d 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -88,7 +88,7 @@ static int call_request_key(struct key *key,
argv[i] = NULL;
/* do it */
- return call_usermodehelper(argv[0], argv, envp, 1);
+ return call_usermodehelper_keys(argv[0], argv, envp, NULL, 1);
} /* end call_request_key() */