| Message ID | 20200714012732.195466-1-yepeilin.cs@gmail.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [Linux-kernel-mentees,v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() | expand |
On Mon, Jul 13, 2020 at 6:29 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> > --- > Thank you for reviewing my patch! I am new to Linux kernel development; would > the log message and errno be appropriate for this case? I think it's good enough, thanks for the fix. Acked-by: Andrii Nakryiko <andriin@fb.com> > > Change in v2: > - Split NULL and IS_ERR cases. > > kernel/bpf/btf.c | 5 +++++ > 1 file changed, 5 insertions(+) > [...]
On Mon, Jul 13, 2020 at 9:38 PM Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Mon, Jul 13, 2020 at 6:29 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 The link looks wrong? Nothing in the stack trace indicates this issue. > > Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com > > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> > > --- > > Thank you for reviewing my patch! I am new to Linux kernel development; would > > the log message and errno be appropriate for this case? > > I think it's good enough, thanks for the fix. > > Acked-by: Andrii Nakryiko <andriin@fb.com> > > > > > 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;
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> --- Thank you for reviewing my patch! I am new to Linux kernel development; would the log message and errno be appropriate for this case? Change in v2: - Split NULL and IS_ERR cases. kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+)