Commit 5b801dfb authored by Peilin Ye's avatar Peilin Ye Committed by Daniel Borkmann
Browse files

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: default avatar <syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com>
Signed-off-by: default avatarPeilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200714180904.277512-1-yepeilin.cs@gmail.com
parent 55b24422

kernel/bpf/btf.c

+5 −0
Original line number Diff line number Diff line
@@ -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;

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