6.9-stable review patch. If anyone has any objections, please let me know.
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From: Stanislav Fomichev sdf@google.com
[ Upstream commit 543576ec15b17c0c93301ac8297333c7b6e84ac7 ]
bpf_prog_attach uses attach_type_to_prog_type to enforce proper attach type for BPF_PROG_TYPE_CGROUP_SKB. link_create uses bpf_prog_get and relies on bpf_prog_attach_check_attach_type to properly verify prog_type <> attach_type association.
Add missing attach_type enforcement for the link_create case. Otherwise, it's currently possible to attach cgroup_skb prog types to other cgroup hooks.
Fixes: af6eea57437a ("bpf: Implement bpf_link-based cgroup BPF program attachment") Link: https://lore.kernel.org/bpf/0000000000004792a90615a1dde0@google.com/ Reported-by: syzbot+838346b979830606c854@syzkaller.appspotmail.com Signed-off-by: Stanislav Fomichev sdf@google.com Acked-by: Eduard Zingerman eddyz87@gmail.com Link: https://lore.kernel.org/r/20240426231621.2716876-2-sdf@google.com Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/syscall.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c287925471f68..cb61d8880dbe0 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3985,6 +3985,11 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, * check permissions at attach time. */ return -EPERM; + + ptype = attach_type_to_prog_type(attach_type); + if (prog->type != ptype) + return -EINVAL; + return prog->enforce_expected_attach_type && prog->expected_attach_type != attach_type ? -EINVAL : 0;