Messages in this thread Patch in this message | | | From | Peilin Ye <> | Subject | [Linux-kernel-mentees] [PATCH v3] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() | Date | Tue, 14 Jul 2020 14:09:04 -0400 |
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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 <yepeilin.cs@gmail.com> --- Sorry, I got the link wrong. Thank you for pointing that out.
Change in v3: - Fix incorrect syzbot dashboard link.
Change in v2: - Split NULL and IS_ERR cases.
kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 30721f2c2d10..092116a311f4 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4088,6 +4088,11 @@ 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; -- 2.25.1
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