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-rw-r--r--net/core/filter.c134
1 files changed, 117 insertions, 17 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 298b146b47e7..0920c2ac1d00 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1362,6 +1362,11 @@ static inline int bpf_try_make_writable(struct sk_buff *skb,
return err;
}
+static int bpf_try_make_head_writable(struct sk_buff *skb)
+{
+ return bpf_try_make_writable(skb, skb_headlen(skb));
+}
+
static inline void bpf_push_mac_rcsum(struct sk_buff *skb)
{
if (skb_at_tc_ingress(skb))
@@ -1441,6 +1446,28 @@ static const struct bpf_func_proto bpf_skb_load_bytes_proto = {
.arg4_type = ARG_CONST_STACK_SIZE,
};
+BPF_CALL_2(bpf_skb_pull_data, struct sk_buff *, skb, u32, len)
+{
+ /* Idea is the following: should the needed direct read/write
+ * test fail during runtime, we can pull in more data and redo
+ * again, since implicitly, we invalidate previous checks here.
+ *
+ * Or, since we know how much we need to make read/writeable,
+ * this can be done once at the program beginning for direct
+ * access case. By this we overcome limitations of only current
+ * headroom being accessible.
+ */
+ return bpf_try_make_writable(skb, len ? : skb_headlen(skb));
+}
+
+static const struct bpf_func_proto bpf_skb_pull_data_proto = {
+ .func = bpf_skb_pull_data,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+};
+
BPF_CALL_5(bpf_l3_csum_replace, struct sk_buff *, skb, u32, offset,
u64, from, u64, to, u64, flags)
{
@@ -1567,6 +1594,7 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size,
static const struct bpf_func_proto bpf_csum_diff_proto = {
.func = bpf_csum_diff,
.gpl_only = false,
+ .pkt_access = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_STACK,
.arg2_type = ARG_CONST_STACK_SIZE_OR_ZERO,
@@ -1575,6 +1603,26 @@ static const struct bpf_func_proto bpf_csum_diff_proto = {
.arg5_type = ARG_ANYTHING,
};
+BPF_CALL_2(bpf_csum_update, struct sk_buff *, skb, __wsum, csum)
+{
+ /* The interface is to be used in combination with bpf_csum_diff()
+ * for direct packet writes. csum rotation for alignment as well
+ * as emulating csum_sub() can be done from the eBPF program.
+ */
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ return (skb->csum = csum_add(skb->csum, csum));
+
+ return -ENOTSUPP;
+}
+
+static const struct bpf_func_proto bpf_csum_update_proto = {
+ .func = bpf_csum_update,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+};
+
static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb)
{
return dev_forward_skb(dev, skb);
@@ -1602,6 +1650,8 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags)
{
struct net_device *dev;
+ struct sk_buff *clone;
+ int ret;
if (unlikely(flags & ~(BPF_F_INGRESS)))
return -EINVAL;
@@ -1610,14 +1660,25 @@ BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags)
if (unlikely(!dev))
return -EINVAL;
- skb = skb_clone(skb, GFP_ATOMIC);
- if (unlikely(!skb))
+ clone = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!clone))
return -ENOMEM;
- bpf_push_mac_rcsum(skb);
+ /* For direct write, we need to keep the invariant that the skbs
+ * we're dealing with need to be uncloned. Should uncloning fail
+ * here, we need to free the just generated clone to unclone once
+ * again.
+ */
+ ret = bpf_try_make_head_writable(skb);
+ if (unlikely(ret)) {
+ kfree_skb(clone);
+ return -ENOMEM;
+ }
+
+ bpf_push_mac_rcsum(clone);
return flags & BPF_F_INGRESS ?
- __bpf_rx_skb(dev, skb) : __bpf_tx_skb(dev, skb);
+ __bpf_rx_skb(dev, clone) : __bpf_tx_skb(dev, clone);
}
static const struct bpf_func_proto bpf_clone_redirect_proto = {
@@ -2063,19 +2124,14 @@ static const struct bpf_func_proto bpf_skb_change_tail_proto = {
bool bpf_helper_changes_skb_data(void *func)
{
- if (func == bpf_skb_vlan_push)
- return true;
- if (func == bpf_skb_vlan_pop)
- return true;
- if (func == bpf_skb_store_bytes)
- return true;
- if (func == bpf_skb_change_proto)
- return true;
- if (func == bpf_skb_change_tail)
- return true;
- if (func == bpf_l3_csum_replace)
- return true;
- if (func == bpf_l4_csum_replace)
+ if (func == bpf_skb_vlan_push ||
+ func == bpf_skb_vlan_pop ||
+ func == bpf_skb_store_bytes ||
+ func == bpf_skb_change_proto ||
+ func == bpf_skb_change_tail ||
+ func == bpf_skb_pull_data ||
+ func == bpf_l3_csum_replace ||
+ func == bpf_l4_csum_replace)
return true;
return false;
@@ -2440,8 +2496,12 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
return &bpf_skb_store_bytes_proto;
case BPF_FUNC_skb_load_bytes:
return &bpf_skb_load_bytes_proto;
+ case BPF_FUNC_skb_pull_data:
+ return &bpf_skb_pull_data_proto;
case BPF_FUNC_csum_diff:
return &bpf_csum_diff_proto;
+ case BPF_FUNC_csum_update:
+ return &bpf_csum_update_proto;
case BPF_FUNC_l3_csum_replace:
return &bpf_l3_csum_replace_proto;
case BPF_FUNC_l4_csum_replace:
@@ -2533,6 +2593,45 @@ static bool sk_filter_is_valid_access(int off, int size,
return __is_valid_access(off, size, type);
}
+static int tc_cls_act_prologue(struct bpf_insn *insn_buf, bool direct_write,
+ const struct bpf_prog *prog)
+{
+ struct bpf_insn *insn = insn_buf;
+
+ if (!direct_write)
+ return 0;
+
+ /* if (!skb->cloned)
+ * goto start;
+ *
+ * (Fast-path, otherwise approximation that we might be
+ * a clone, do the rest in helper.)
+ */
+ *insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_6, BPF_REG_1, CLONED_OFFSET());
+ *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_6, CLONED_MASK);
+ *insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 7);
+
+ /* ret = bpf_skb_pull_data(skb, 0); */
+ *insn++ = BPF_MOV64_REG(BPF_REG_6, BPF_REG_1);
+ *insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_2, BPF_REG_2);
+ *insn++ = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_skb_pull_data);
+ /* if (!ret)
+ * goto restore;
+ * return TC_ACT_SHOT;
+ */
+ *insn++ = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2);
+ *insn++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, TC_ACT_SHOT);
+ *insn++ = BPF_EXIT_INSN();
+
+ /* restore: */
+ *insn++ = BPF_MOV64_REG(BPF_REG_1, BPF_REG_6);
+ /* start: */
+ *insn++ = prog->insnsi[0];
+
+ return insn - insn_buf;
+}
+
static bool tc_cls_act_is_valid_access(int off, int size,
enum bpf_access_type type,
enum bpf_reg_type *reg_type)
@@ -2810,6 +2909,7 @@ static const struct bpf_verifier_ops tc_cls_act_ops = {
.get_func_proto = tc_cls_act_func_proto,
.is_valid_access = tc_cls_act_is_valid_access,
.convert_ctx_access = tc_cls_act_convert_ctx_access,
+ .gen_prologue = tc_cls_act_prologue,
};
static const struct bpf_verifier_ops xdp_ops = {
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 18:24:50 +0100