Re: [PATCH v2 3/5] ebpf: add a way to dump an eBPF program
From: Alexei Starovoitov <hidden>
Date: 2015-09-11 02:29:48
Also in:
linux-api, lkml
From: Alexei Starovoitov <hidden>
Date: 2015-09-11 02:29:48
Also in:
linux-api, lkml
On Thu, Sep 10, 2015 at 06:21:00PM -0600, Tycho Andersen wrote:
+static int bpf_prog_dump(union bpf_attr *attr, union bpf_attr __user *uattr)
+{
+ int ufd = attr->prog_fd;
+ struct fd f = fdget(ufd);
+ struct bpf_prog *prog;
+ int ret = -EINVAL;
+
+ prog = get_prog(f);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+
+ /* For now, let's refuse to dump anything that isn't a seccomp program.
+ * Other program types have support for maps, which our current dump
+ * code doesn't support.
+ */
+ if (prog->type != BPF_PROG_TYPE_SECCOMP)
+ goto out;
+
+ ret = -EFAULT;
+ if (put_user(prog->len, &uattr->dump_insn_cnt))
+ goto out;
+
+ if (put_user((u8) prog->gpl_compatible, &uattr->gpl_compatible))
+ goto out;
+
+ if (attr->dump_insns) {
+ u32 len = prog->len * sizeof(struct bpf_insn);
+
+ if (copy_to_user(u64_to_ptr(attr->dump_insns),
+ prog->insns, len) != 0)
+ goto out;
+ }
+
+ ret = 0;
+out:
+ return ret;fdput() is missing in all error paths.