[PATCH net-next 3/7] ebpf: check first for MAXINSNS in bpf_prog_load
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2015-02-11 00:15:34
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Just minor ... before doing all the copying work, we may want to check for instruction count earlier. Also, we may want to warn the user in case we would otherwise need to truncate the license information. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> --- kernel/bpf/syscall.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 536edc2..73b105c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c@@ -473,25 +473,26 @@ static int bpf_prog_load(union bpf_attr *attr) { enum bpf_prog_type type = attr->prog_type; struct bpf_prog *prog; - int err; char license[128]; bool is_gpl; + int err; if (CHECK_ATTR(BPF_PROG_LOAD)) return -EINVAL; + if (attr->insn_cnt >= BPF_MAXINSNS) + return -EINVAL; /* copy eBPF program license from user space */ - if (strncpy_from_user(license, u64_to_ptr(attr->license), - sizeof(license) - 1) < 0) - return -EFAULT; - license[sizeof(license) - 1] = 0; + err = strncpy_from_user(license, u64_to_ptr(attr->license), + sizeof(license)); + if (err == sizeof(license)) + err = -ERANGE; + if (err < 0) + return err; /* eBPF programs must be GPL compatible to use GPL-ed functions */ is_gpl = license_is_gpl_compatible(license); - if (attr->insn_cnt >= BPF_MAXINSNS) - return -EINVAL; - /* plain bpf_prog allocation */ prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); if (!prog)
--
1.9.3