[PATCH] mm/page_alloc.c: add additional checking and return value for the 'table->data'

[Chen Gang]

If 'table->data' is invalid, also need check its length to know whether
is invalid, firstly.

When __parse_numa_zonelist_order() fails, also need save the related
error code for return.

Beautify code ('char*' --> 'char *') to pass "./scripts/checkpatch.pl"


Signed-off-by: Chen Gang <gang.c...@asianux.com>
---
 mm/page_alloc.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0a0acfe..48c83e4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3250,18 +3250,25 @@ int numa_zonelist_order_handler(ctl_table *table, int 
write,
        static DEFINE_MUTEX(zl_order_mutex);
 
        mutex_lock(&zl_order_mutex);
-       if (write)
-               strcpy(saved_string, (char*)table->data);
+       if (write) {
+               if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
+                       ret = -EINVAL;
+                       goto out;
+               }
+               strcpy(saved_string, (char *)table->data);
+       }
        ret = proc_dostring(table, write, buffer, length, ppos);
        if (ret)
                goto out;
        if (write) {
                int oldval = user_zonelist_order;
-               if (__parse_numa_zonelist_order((char*)table->data)) {
+
+               ret = __parse_numa_zonelist_order((char *)table->data);
+               if (ret) {
                        /*
                         * bogus value.  restore saved string
                         */
-                       strncpy((char*)table->data, saved_string,
+                       strncpy((char *)table->data, saved_string,
                                NUMA_ZONELIST_ORDER_LEN);
                        user_zonelist_order = oldval;
                } else if (oldval != user_zonelist_order) {
-- 
1.7.7.6
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