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Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index b2ebaee8c377..a23315dc4498 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -261,6 +261,12 @@ 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 +274,20 @@ 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;
@@ -1063,13 +1082,15 @@ void printk_tick(void)
int printk_needs_cpu(int cpu)
{
+ if (unlikely(cpu_is_offline(cpu)))
+ printk_tick();
return per_cpu(printk_pending, cpu);
}
void wake_up_klogd(void)
{
if (waitqueue_active(&log_wait))
- __raw_get_cpu_var(printk_pending) = 1;
+ this_cpu_write(printk_pending, 1);
}
/**