From: Xi Wang Date: Thu, 22 Dec 2011 13:35:22 +0000 (+0000) Subject: rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt() X-Git-Tag: v3.2-rc7~7^2~2 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=a0a129f8b6cff54ab479324a54aefdab5db4f240;ds=sidebyside 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 Signed-off-by: Xi Wang Signed-off-by: David S. Miller --- diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index c71c434a4c05..385aefe53648 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -665,11 +665,14 @@ static ssize_t store_rps_dev_flow_table_cnt(struct netdev_rx_queue *queue, 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;