Messages in this thread Patch in this message | | | From | Peilin Ye <> | Subject | [Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() | Date | Mon, 13 Jul 2020 21:27:32 -0400 |
| |
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(+)
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
| |