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authorDavid Ahern <dsa@cumulusnetworks.com>2016-12-01 19:48:04 +0300
committerDavid S. Miller <davem@davemloft.net>2016-12-02 21:46:08 +0300
commit61023658760032e97869b07d54be9681d2529e77 (patch)
tree9b10a9d2a8b5820450298f9bda8f3c23fbf66b57 /net/core
parentb2cd12574aa3e1625f471ff57cde7f628a18a46b (diff)
downloadlinux-61023658760032e97869b07d54be9681d2529e77.tar.xz
bpf: Add new cgroup attach type to enable sock modifications
Add new cgroup based program type, BPF_PROG_TYPE_CGROUP_SOCK. Similar to BPF_PROG_TYPE_CGROUP_SKB programs can be attached to a cgroup and run any time a process in the cgroup opens an AF_INET or AF_INET6 socket. Currently only sk_bound_dev_if is exported to userspace for modification by a bpf program. This allows a cgroup to be configured such that AF_INET{6} sockets opened by processes are automatically bound to a specific device. In turn, this enables the running of programs that do not support SO_BINDTODEVICE in a specific VRF context / L3 domain. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 1c4d0faf22c8..0ab252e462aa 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2818,6 +2818,32 @@ static bool lwt_is_valid_access(int off, int size,
return __is_valid_access(off, size, type);
}
+static bool sock_filter_is_valid_access(int off, int size,
+ enum bpf_access_type type,
+ enum bpf_reg_type *reg_type)
+{
+ if (type == BPF_WRITE) {
+ switch (off) {
+ case offsetof(struct bpf_sock, bound_dev_if):
+ break;
+ default:
+ return false;
+ }
+ }
+
+ if (off < 0 || off + size > sizeof(struct bpf_sock))
+ return false;
+
+ /* The verifier guarantees that size > 0. */
+ if (off % size != 0)
+ return false;
+
+ if (size != sizeof(__u32))
+ return false;
+
+ return true;
+}
+
static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
const struct bpf_prog *prog)
{
@@ -3076,6 +3102,30 @@ static u32 sk_filter_convert_ctx_access(enum bpf_access_type type, int dst_reg,
return insn - insn_buf;
}
+static u32 sock_filter_convert_ctx_access(enum bpf_access_type type,
+ int dst_reg, int src_reg,
+ int ctx_off,
+ struct bpf_insn *insn_buf,
+ struct bpf_prog *prog)
+{
+ struct bpf_insn *insn = insn_buf;
+
+ switch (ctx_off) {
+ case offsetof(struct bpf_sock, bound_dev_if):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sock, sk_bound_dev_if) != 4);
+
+ if (type == BPF_WRITE)
+ *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg,
+ offsetof(struct sock, sk_bound_dev_if));
+ else
+ *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg,
+ offsetof(struct sock, sk_bound_dev_if));
+ break;
+ }
+
+ return insn - insn_buf;
+}
+
static u32 tc_cls_act_convert_ctx_access(enum bpf_access_type type, int dst_reg,
int src_reg, int ctx_off,
struct bpf_insn *insn_buf,
@@ -3162,6 +3212,12 @@ static const struct bpf_verifier_ops lwt_xmit_ops = {
.gen_prologue = tc_cls_act_prologue,
};
+static const struct bpf_verifier_ops cg_sock_ops = {
+ .get_func_proto = sk_filter_func_proto,
+ .is_valid_access = sock_filter_is_valid_access,
+ .convert_ctx_access = sock_filter_convert_ctx_access,
+};
+
static struct bpf_prog_type_list sk_filter_type __read_mostly = {
.ops = &sk_filter_ops,
.type = BPF_PROG_TYPE_SOCKET_FILTER,
@@ -3202,6 +3258,11 @@ static struct bpf_prog_type_list lwt_xmit_type __read_mostly = {
.type = BPF_PROG_TYPE_LWT_XMIT,
};
+static struct bpf_prog_type_list cg_sock_type __read_mostly = {
+ .ops = &cg_sock_ops,
+ .type = BPF_PROG_TYPE_CGROUP_SOCK
+};
+
static int __init register_sk_filter_ops(void)
{
bpf_register_prog_type(&sk_filter_type);
@@ -3209,6 +3270,7 @@ static int __init register_sk_filter_ops(void)
bpf_register_prog_type(&sched_act_type);
bpf_register_prog_type(&xdp_type);
bpf_register_prog_type(&cg_skb_type);
+ bpf_register_prog_type(&cg_sock_type);
bpf_register_prog_type(&lwt_in_type);
bpf_register_prog_type(&lwt_out_type);
bpf_register_prog_type(&lwt_xmit_type);