1 files changed, 28 insertions, 11 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index b2ebaee8c377..4642a5c439eb 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -43,12 +43,6 @@
 #include <asm/uaccess.h>
 
 /*
- * for_each_console() allows you to iterate on each console
- */
-#define for_each_console(con) \
-        for (con = console_drivers; con != NULL; con = con->next)
-
-/*
  * Architectures can override it:
  */
 void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
@@ -261,6 +255,12 @@ static inline void boot_delay_msec(void)
 }
 #endif
 
+#ifdef CONFIG_SECURITY_DMESG_RESTRICT
+int dmesg_restrict = 1;
+#else
+int dmesg_restrict;
+#endif
+
 int do_syslog(int type, char __user *buf, int len, bool from_file)
 {
         unsigned i, j, limit, count;
@@ -268,7 +268,20 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
         char c;
         int error = 0;
 
-        error = security_syslog(type, from_file);
+        /*
+         * If this is from /proc/kmsg we only do the capabilities checks
+         * at open time.
+         */
+        if (type == SYSLOG_ACTION_OPEN || !from_file) {
+                if (dmesg_restrict && !capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+                if ((type != SYSLOG_ACTION_READ_ALL &&
+                     type != SYSLOG_ACTION_SIZE_BUFFER) &&
+                    !capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+        }
+
+        error = security_syslog(type);
         if (error)
                 return error;
 
@@ -1055,21 +1068,23 @@ static DEFINE_PER_CPU(int, printk_pending);
 
 void printk_tick(void)
 {
-        if (__get_cpu_var(printk_pending)) {
-                __get_cpu_var(printk_pending) = 0;
+        if (__this_cpu_read(printk_pending)) {
+                __this_cpu_write(printk_pending, 0);
                 wake_up_interruptible(&log_wait);
         }
 }
 
 int printk_needs_cpu(int cpu)
 {
-        return per_cpu(printk_pending, cpu);
+        if (cpu_is_offline(cpu))
+                printk_tick();
+        return __this_cpu_read(printk_pending);
 }
 
 void wake_up_klogd(void)
 {
         if (waitqueue_active(&log_wait))
-                __raw_get_cpu_var(printk_pending) = 1;
+                this_cpu_write(printk_pending, 1);
 }
 
 /**
@@ -1338,6 +1353,7 @@ void register_console(struct console *newcon)
                 spin_unlock_irqrestore(&logbuf_lock, flags);
         }
         release_console_sem();
+        console_sysfs_notify();
 
         /*
          * By unregistering the bootconsoles after we enable the real console
@@ -1396,6 +1412,7 @@ int unregister_console(struct console *console)
                 console_drivers->flags |= CON_CONSDEV;
 
         release_console_sem();
+        console_sysfs_notify();
         return res;
 }
 EXPORT_SYMBOL(unregister_console);