From 5b801dfb7feb2738975d80223efc2fc193e55573 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Tue, 14 Jul 2020 14:09:04 -0400 Subject: bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux` as NULL. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=f823224ada908fa5c207902a5a62065e53ca0fcc Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com Signed-off-by: Peilin Ye Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200714180904.277512-1-yepeilin.cs@gmail.com --- kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 9a1a98dd9e97..0443600146dc 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4058,6 +4058,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, const char *tname, *sym; u32 btf_id, i; + if (!btf_vmlinux) { + bpf_log(log, "btf_vmlinux doesn't exist\n"); + return -EINVAL; + } + if (IS_ERR(btf_vmlinux)) { bpf_log(log, "btf_vmlinux is malformed\n"); return -EINVAL; -- cgit