For multiple mode-setting callers, we will need a helper to perform the
sanity-checking and finalization logic while the seccomp lock is held.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
kernel/seccomp.c | 42 +++++++++++++++++++++++++-----------------
1 file changed, 25 insertions(+), 17 deletions(-)
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 6d61a0b5080c..440dc2c213ac 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -462,26 +462,11 @@ long prctl_get_seccomp(void)
return current->seccomp.mode;
}
-/**
- * prctl_set_seccomp: configures current->seccomp.mode
- * @seccomp_mode: requested mode to use
- * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
- *
- * This function may be called repeatedly with a @seccomp_mode of
- * SECCOMP_MODE_FILTER to install additional filters. Every filter
- * successfully installed will be evaluated (in reverse order) for each system
- * call the task makes.
- *
- * Once current->seccomp.mode is non-zero, it may not be changed.
- *
- * Returns 0 on success or -EINVAL on failure.
- */
-long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
+/* Expects to be called under seccomp lock. */
+static long _seccomp_set_mode(unsigned long seccomp_mode, char * __user filter)
{
long ret = -EINVAL;
- seccomp_lock(current);
-
if (current->seccomp.mode &&
current->seccomp.mode != seccomp_mode)
goto out;
@@ -507,6 +492,29 @@ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
current->seccomp.mode = seccomp_mode;
set_thread_flag(TIF_SECCOMP);
out:
+ return ret;
+}
+
+/**
+ * prctl_set_seccomp: configures current->seccomp.mode
+ * @seccomp_mode: requested mode to use
+ * @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
+ *
+ * This function may be called repeatedly with a @seccomp_mode of
+ * SECCOMP_MODE_FILTER to install additional filters. Every filter
+ * successfully installed will be evaluated (in reverse order) for each system
+ * call the task makes.
+ *
+ * Once current->seccomp.mode is non-zero, it may not be changed.
+ *
+ * Returns 0 on success or -EINVAL on failure.
+ */
+long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter)
+{
+ long ret;
+
+ seccomp_lock(current);
+ ret = _seccomp_set_mode(seccomp_mode, filter);
seccomp_unlock(current);
return ret;
}
--
1.7.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
