rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt()
Setting a large rps_flow_cnt like (1 << 30) on 32-bit platform will
cause a kernel oops due to insufficient bounds checking.
if (count > 1<<30) {
/* Enforce a limit to prevent overflow */
return -EINVAL;
}
count = roundup_pow_of_two(count);
table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count));
Note that the macro RPS_DEV_FLOW_TABLE_SIZE(count) is defined as:
... + (count * sizeof(struct rps_dev_flow))
where sizeof(struct rps_dev_flow) is 8. (1 << 30) * 8 will overflow
32 bits.
This patch replaces the magic number (1 << 30) with a symbolic bound.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c71c434..385aefe 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -665,11 +665,14 @@
if (count) {
int i;
- if (count > 1<<30) {
+ if (count > INT_MAX)
+ return -EINVAL;
+ count = roundup_pow_of_two(count);
+ if (count > (ULONG_MAX - sizeof(struct rps_dev_flow_table))
+ / sizeof(struct rps_dev_flow)) {
/* Enforce a limit to prevent overflow */
return -EINVAL;
}
- count = roundup_pow_of_two(count);
table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count));
if (!table)
return -ENOMEM;