xdp: allow attaching programs loaded for specific device

Pass the netdev pointer to bpf_prog_get_type().  This way
BPF code can decide whether the device matches what the
code was loaded/translated for.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 29 insertions, 4 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3217c20ea91b..68f9123acd39 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1057,7 +1057,22 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
 
-static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type)
+static bool bpf_prog_can_attach(struct bpf_prog *prog,
+                                enum bpf_prog_type *attach_type,
+                                struct net_device *netdev)
+{
+        struct bpf_dev_offload *offload = prog->aux->offload;
+
+        if (prog->type != *attach_type)
+                return false;
+        if (offload && offload->netdev != netdev)
+                return false;
+
+        return true;
+}
+
+static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
+                                       struct net_device *netdev)
 {
         struct fd f = fdget(ufd);
         struct bpf_prog *prog;
@@ -1065,7 +1080,7 @@ static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type)
         prog = ____bpf_prog_get(f);
         if (IS_ERR(prog))
                 return prog;
-        if (attach_type && (prog->type != *attach_type || prog->aux->offload)) {
+        if (attach_type && !bpf_prog_can_attach(prog, attach_type, netdev)) {
                 prog = ERR_PTR(-EINVAL);
                 goto out;
         }
@@ -1078,12 +1093,12 @@ out:
 
 struct bpf_prog *bpf_prog_get(u32 ufd)
 {
-        return __bpf_prog_get(ufd, NULL);
+        return __bpf_prog_get(ufd, NULL, NULL);
 }
 
 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
 {
-        struct bpf_prog *prog = __bpf_prog_get(ufd, &type);
+        struct bpf_prog *prog = __bpf_prog_get(ufd, &type, NULL);
 
         if (!IS_ERR(prog))
                 trace_bpf_prog_get_type(prog);
@@ -1091,6 +1106,16 @@ struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_get_type);
 
+struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
+                                       struct net_device *netdev)
+{
+        struct bpf_prog *prog = __bpf_prog_get(ufd, &type, netdev);
+
+        if (!IS_ERR(prog))
+                trace_bpf_prog_get_type(prog);
+        return prog;
+}
+
 /* last field in 'union bpf_attr' used by this command */
 #define BPF_PROG_LOAD_LAST_FIELD prog_target_ifindex