[PATCH 3.5 31/64] powerpc/pseries/lparcfg: Fix possible overflow are more than 1026

[Luis Henriques]

3.5.7.24 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chen Gang <gang.chen at asianux.com>

commit 5676005acf26ab7e924a8438ea4746e47d405762 upstream.

need set '\0' for 'local_buffer'.

SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
rtas_data_buf may truncated in memcpy.

if contents are really truncated.
  the splpar_strlen is more than 1026. the next while loop checking will
  not find the end of buffer. that will cause memory access violation.

Signed-off-by: Chen Gang <gang.chen at asianux.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/powerpc/kernel/lparcfg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 7ebbae0..f62fda1 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -307,6 +307,7 @@ static void parse_system_parameter_string(struct seq_file *m)
 				__pa(rtas_data_buf),
 				RTAS_DATA_BUF_SIZE);
 	memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
+	local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
 	spin_unlock(&rtas_data_buf_lock);
 
 	if (call_status != 0) {
-- 
1.8.3.2