From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Tue, 16 Oct 2018 15:19:10 -0700
Subject: nfp: bpf: double check vNIC capabilities after object sharing
Patch-mainline: v4.20-rc1
Git-commit: 44b6fed0c16ea0057292d57c381a31e8986fa7a7
References: bsc#1109837

Program translation stage checks that program can be offloaded to
the netdev which was passed during the load (bpf_attr->prog_ifindex).
After program sharing was introduced, however, the netdev on which
program is loaded can theoretically be different, and therefore
we should recheck the program size and max stack size at load time.

This was found by code inspection, AFAIK today all vNICs have
identical caps.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.h     |    3 +++
 drivers/net/ethernet/netronome/nfp/bpf/offload.c  |   14 +++++++++++++-
 drivers/net/ethernet/netronome/nfp/bpf/verifier.c |   11 ++++++-----
 3 files changed, 22 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h
@@ -441,6 +441,7 @@ struct nfp_bpf_subprog_info {
  * @prog: machine code
  * @prog_len: number of valid instructions in @prog array
  * @__prog_alloc_len: alloc size of @prog array
+ * @stack_size: total amount of stack used
  * @verifier_meta: temporary storage for verifier's insn meta
  * @type: BPF program type
  * @last_bpf_off: address of the last instruction translated from BPF
@@ -465,6 +466,8 @@ struct nfp_prog {
 	unsigned int prog_len;
 	unsigned int __prog_alloc_len;
 
+	unsigned int stack_size;
+
 	struct nfp_insn_meta *verifier_meta;
 
 	enum bpf_prog_type type;
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
@@ -489,7 +489,7 @@ nfp_net_bpf_load(struct nfp_net *nn, str
 		 struct netlink_ext_ack *extack)
 {
 	struct nfp_prog *nfp_prog = prog->aux->offload->dev_priv;
-	unsigned int max_mtu;
+	unsigned int max_mtu, max_stack, max_prog_len;
 	dma_addr_t dma_addr;
 	void *img;
 	int err;
@@ -500,6 +500,18 @@ nfp_net_bpf_load(struct nfp_net *nn, str
 		return -EOPNOTSUPP;
 	}
 
+	max_stack = nn_readb(nn, NFP_NET_CFG_BPF_STACK_SZ) * 64;
+	if (nfp_prog->stack_size > max_stack) {
+		NL_SET_ERR_MSG_MOD(extack, "stack too large");
+		return -EOPNOTSUPP;
+	}
+
+	max_prog_len = nn_readw(nn, NFP_NET_CFG_BPF_MAX_LEN);
+	if (nfp_prog->prog_len > max_prog_len) {
+		NL_SET_ERR_MSG_MOD(extack, "program too long");
+		return -EOPNOTSUPP;
+	}
+
 	img = nfp_bpf_relo_for_vnic(nfp_prog, nn->app_priv);
 	if (IS_ERR(img))
 		return PTR_ERR(img);
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -747,9 +747,9 @@ continue_subprog:
 
 static int nfp_bpf_finalize(struct bpf_verifier_env *env)
 {
-	unsigned int stack_size, stack_needed;
 	struct bpf_subprog_info *info;
 	struct nfp_prog *nfp_prog;
+	unsigned int max_stack;
 	struct nfp_net *nn;
 	int i;
 
@@ -777,11 +777,12 @@ static int nfp_bpf_finalize(struct bpf_v
 	}
 
 	nn = netdev_priv(env->prog->aux->offload->netdev);
-	stack_size = nn_readb(nn, NFP_NET_CFG_BPF_STACK_SZ) * 64;
-	stack_needed = nfp_bpf_get_stack_usage(nfp_prog, env->prog->len);
-	if (stack_needed > stack_size) {
+	max_stack = nn_readb(nn, NFP_NET_CFG_BPF_STACK_SZ) * 64;
+	nfp_prog->stack_size = nfp_bpf_get_stack_usage(nfp_prog,
+						       env->prog->len);
+	if (nfp_prog->stack_size > max_stack) {
 		pr_vlog(env, "stack too large: program %dB > FW stack %dB\n",
-			stack_needed, stack_size);
+			nfp_prog->stack_size, max_stack);
 		return -EOPNOTSUPP;
 	}