From d1e37e74378b0ae8bb34b039d1084663863fa1e9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 13 Dec 2024 17:25:18 +0000 Subject: [PATCH] netdevsim: prevent bad user input in nsim_dev_health_break_write() [ Upstream commit ee76746387f6233bdfa93d7406990f923641568f ] If either a zero count or a large one is provided, kernel can crash. Fixes: 82c93a87bf8b ("netdevsim: implement couple of testing devlink health reporters") Reported-by: syzbot+ea40e4294e58b0292f74@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/675c6862.050a0220.37aaf.00b1.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Jiri Pirko Reviewed-by: Joe Damato Link: https://patch.msgid.link/20241213172518.2415666-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/netdevsim/health.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/netdevsim/health.c b/drivers/net/netdevsim/health.c index 04aebdf85..c9306506b 100755 --- a/drivers/net/netdevsim/health.c +++ b/drivers/net/netdevsim/health.c @@ -235,6 +235,8 @@ static ssize_t nsim_dev_health_break_write(struct file *file, char *break_msg; int err; + if (count == 0 || count > PAGE_SIZE) + return -EINVAL; break_msg = memdup_user_nul(data, count); if (IS_ERR(break_msg)) return PTR_ERR(break_msg);