This is a note to let you know that I've just added the patch titled net/sched: flower: fix possible OOB write in fl_set_geneve_opt() to the 6.3-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-sched-flower-fix-possible-oob-write-in-fl_set_ge.patch and it can be found in the queue-6.3 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ce87e67f4e51d2d5d7fdb549a843ea6ed68877db Author: Hangyu Hua <hbh25y@xxxxxxxxx> Date: Wed May 31 18:28:04 2023 +0800 net/sched: flower: fix possible OOB write in fl_set_geneve_opt() [ Upstream commit 4d56304e5827c8cc8cc18c75343d283af7c4825c ] If we send two TCA_FLOWER_KEY_ENC_OPTS_GENEVE packets and their total size is 252 bytes(key->enc_opts.len = 252) then key->enc_opts.len = opt->length = data_len / 4 = 0 when the third TCA_FLOWER_KEY_ENC_OPTS_GENEVE packet enters fl_set_geneve_opt. This bypasses the next bounds check and results in an out-of-bounds. Fixes: 0a6e77784f49 ("net/sched: allow flower to match tunnel options") Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx> Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@xxxxxxx> Link: https://lore.kernel.org/r/20230531102805.27090-1-hbh25y@xxxxxxxxx Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index a1c4ee2e0be22..fd5dc47cb2134 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -1153,6 +1153,9 @@ static int fl_set_geneve_opt(const struct nlattr *nla, struct fl_flow_key *key, if (option_len > sizeof(struct geneve_opt)) data_len = option_len - sizeof(struct geneve_opt); + if (key->enc_opts.len > FLOW_DIS_TUN_OPTS_MAX - 4) + return -ERANGE; + opt = (struct geneve_opt *)&key->enc_opts.data[key->enc_opts.len]; memset(opt, 0xff, option_len); opt->length = data_len / 4;