kprobes: Prohibit probing on .entry.text code

.entry.text is a code area which is used for interrupt/syscall
entries, which includes many sensitive code.
Thus, it is better to prohibit probing on all of such code
instead of a part of that.
Since some symbols are already registered on kprobe blacklist,
this also removes them from the blacklist.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20140417081658.26341.57354.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ceeadfcabb76..5b5ac76671e7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -96,9 +96,6 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
 static struct kprobe_blackpoint kprobe_blacklist[] = {
         {"preempt_schedule",},
         {"native_get_debugreg",},
-        {"irq_entries_start",},
-        {"common_interrupt",},
-        {"mcount",},    /* mcount can be called from everywhere */
         {NULL}    /* Terminator */
 };
 
@@ -1324,12 +1321,18 @@ out:
         return ret;
 }
 
+bool __weak arch_within_kprobe_blacklist(unsigned long addr)
+{
+        /* The __kprobes marked functions and entry code must not be probed */
+        return addr >= (unsigned long)__kprobes_text_start &&
+               addr < (unsigned long)__kprobes_text_end;
+}
+
 static int __kprobes in_kprobes_functions(unsigned long addr)
 {
         struct kprobe_blackpoint *kb;
 
-        if (addr >= (unsigned long)__kprobes_text_start &&
-            addr < (unsigned long)__kprobes_text_end)
+        if (arch_within_kprobe_blacklist(addr))
                 return -EINVAL;
         /*
          * If there exists a kprobe_blacklist, verify and