| Message ID | 20200714003856.194768-1-yepeilin.cs@gmail.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [Linux-kernel-mentees] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() | expand |
On Mon, Jul 13, 2020 at 5:43 PM Peilin Ye <yepeilin.cs@gmail.com> wrote: > > Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux` > as NULL. This patch fixes the following syzbot bug: > > https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355 > > Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> > --- > kernel/bpf/btf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 30721f2c2d10..3e981b183fa4 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -4088,7 +4088,7 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, > const char *tname, *sym; > u32 btf_id, i; > > - if (IS_ERR(btf_vmlinux)) { > + if (IS_ERR_OR_NULL(btf_vmlinux)) { > bpf_log(log, "btf_vmlinux is malformed\n"); Can you please split IS_ERR and NULL cases and emit different messages to log? If the kernel is not built with btf_vmlinux, saying that it's "malformed" will confuse people. Thanks. > return -EINVAL; > } > -- > 2.25.1 >
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 30721f2c2d10..3e981b183fa4 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4088,7 +4088,7 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, const char *tname, *sym; u32 btf_id, i; - if (IS_ERR(btf_vmlinux)) { + if (IS_ERR_OR_NULL(btf_vmlinux)) { bpf_log(log, "btf_vmlinux is malformed\n"); return -EINVAL; }
Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux` as NULL. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355 Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> --- kernel/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)