From: 王贇 yun.wang@linux.alibaba.com
[ Upstream commit b193e15ac69d56f35e1d8e2b5d16cbd47764d053 ]
We observed below report when playing with netlink sock:
UBSAN: shift-out-of-bounds in net/sched/sch_api.c:580:10 shift exponent 249 is too large for 32-bit type CPU: 0 PID: 685 Comm: a.out Not tainted Call Trace: dump_stack_lvl+0x8d/0xcf ubsan_epilogue+0xa/0x4e __ubsan_handle_shift_out_of_bounds+0x161/0x182 __qdisc_calculate_pkt_len+0xf0/0x190 __dev_queue_xmit+0x2ed/0x15b0
it seems like kernel won't check the stab log value passing from user, and will use the insane value later to calculate pkt_len.
This patch just add a check on the size/cell_log to avoid insane calculation.
Reported-by: Abaci abaci@linux.alibaba.com Signed-off-by: Michael Wang yun.wang@linux.alibaba.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/pkt_sched.h | 1 + net/sched/sch_api.c | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index b16f9236de14..d1585b54fb0b 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -11,6 +11,7 @@ #include <uapi/linux/pkt_sched.h>
#define DEFAULT_TX_QUEUE_LEN 1000 +#define STAB_SIZE_LOG_MAX 30
struct qdisc_walker { int stop; diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 3b1b5ee52137..e70f99033408 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -510,6 +510,12 @@ static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt, return stab; }
+ if (s->size_log > STAB_SIZE_LOG_MAX || + s->cell_log > STAB_SIZE_LOG_MAX) { + NL_SET_ERR_MSG(extack, "Invalid logarithmic size of size table"); + return ERR_PTR(-EINVAL); + } + stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL); if (!stab) return ERR_PTR(-ENOMEM);