From 5f2ae606cb5a90839a9be9d22388c4200f820e75 Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Sat, 17 Feb 2024 19:41:51 +0800 Subject: [PATCH] bpf: Fix an issue due to uninitialized bpf_iter_task Failure to initialize it->pos, coupled with the presence of an invalid value in the flags variable, can lead to it->pos referencing an invalid task, potentially resulting in a kernel panic. To mitigate this risk, it's crucial to ensure proper initialization of it->pos to NULL. Fixes: ac8148d957f5 ("bpf: bpf_iter_task_next: use next_task(kit->task) rather than next_task(kit->pos)") Signed-off-by: Yafang Shao Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Oleg Nesterov Link: https://lore.kernel.org/bpf/20240217114152.1623-2-laoar.shao@gmail.com --- kernel/bpf/task_iter.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index e5c3500443c6..ec4e97c61eef 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -978,6 +978,8 @@ __bpf_kfunc int bpf_iter_task_new(struct bpf_iter_task *it, BUILD_BUG_ON(__alignof__(struct bpf_iter_task_kern) != __alignof__(struct bpf_iter_task)); + kit->pos = NULL; + switch (flags) { case BPF_TASK_ITER_ALL_THREADS: case BPF_TASK_ITER_ALL_PROCS: