From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit 23f68d462984bfda47c7bf663dca347e8e3df549 ]
Allow up to 16-byte comparisons with a new cmp fast version. Use two 64-bit words and calculate the mask representing the bits to be compared. Make sure the comparison is 64-bit aligned and avoid out-of-bound memory access on registers.
Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/netfilter/nf_tables_core.h | 9 +++ net/netfilter/nf_tables_core.c | 16 ++++ net/netfilter/nft_cmp.c | 102 ++++++++++++++++++++++++- 3 files changed, 125 insertions(+), 2 deletions(-)
diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h index 0fa5a6d98a00b..9dfa11d4224d2 100644 --- a/include/net/netfilter/nf_tables_core.h +++ b/include/net/netfilter/nf_tables_core.h @@ -40,6 +40,14 @@ struct nft_cmp_fast_expr { bool inv; };
+struct nft_cmp16_fast_expr { + struct nft_data data; + struct nft_data mask; + u8 sreg; + u8 len; + bool inv; +}; + struct nft_immediate_expr { struct nft_data data; u8 dreg; @@ -57,6 +65,7 @@ static inline u32 nft_cmp_fast_mask(unsigned int len) }
extern const struct nft_expr_ops nft_cmp_fast_ops; +extern const struct nft_expr_ops nft_cmp16_fast_ops;
struct nft_payload { enum nft_payload_bases base:8; diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index 7defe5a92e47f..2ab4216d2a903 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -67,6 +67,20 @@ static void nft_cmp_fast_eval(const struct nft_expr *expr, regs->verdict.code = NFT_BREAK; }
+static void nft_cmp16_fast_eval(const struct nft_expr *expr, + struct nft_regs *regs) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + const u64 *reg_data = (const u64 *)®s->data[priv->sreg]; + const u64 *mask = (const u64 *)&priv->mask; + const u64 *data = (const u64 *)&priv->data; + + if (((reg_data[0] & mask[0]) == data[0] && + ((reg_data[1] & mask[1]) == data[1])) ^ priv->inv) + return; + regs->verdict.code = NFT_BREAK; +} + static noinline void __nft_trace_verdict(struct nft_traceinfo *info, const struct nft_chain *chain, const struct nft_regs *regs) @@ -215,6 +229,8 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv) nft_rule_for_each_expr(expr, last, rule) { if (expr->ops == &nft_cmp_fast_ops) nft_cmp_fast_eval(expr, ®s); + else if (expr->ops == &nft_cmp16_fast_ops) + nft_cmp16_fast_eval(expr, ®s); else if (expr->ops == &nft_bitwise_fast_ops) nft_bitwise_fast_eval(expr, ®s); else if (expr->ops != &nft_payload_fast_ops || diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c index 47b6d05f1ae69..917072af09df9 100644 --- a/net/netfilter/nft_cmp.c +++ b/net/netfilter/nft_cmp.c @@ -272,12 +272,103 @@ const struct nft_expr_ops nft_cmp_fast_ops = { .offload = nft_cmp_fast_offload, };
+static u32 nft_cmp_mask(u32 bitlen) +{ + return (__force u32)cpu_to_le32(~0U >> (sizeof(u32) * BITS_PER_BYTE - bitlen)); +} + +static void nft_cmp16_fast_mask(struct nft_data *data, unsigned int bitlen) +{ + int len = bitlen / BITS_PER_BYTE; + int i, words = len / sizeof(u32); + + for (i = 0; i < words; i++) { + data->data[i] = 0xffffffff; + bitlen -= sizeof(u32) * BITS_PER_BYTE; + } + + if (len % sizeof(u32)) + data->data[i++] = nft_cmp_mask(bitlen); + + for (; i < 4; i++) + data->data[i] = 0; +} + +static int nft_cmp16_fast_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + struct nft_data_desc desc; + int err; + + err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, + tb[NFTA_CMP_DATA]); + if (err < 0) + return err; + + err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len); + if (err < 0) + return err; + + nft_cmp16_fast_mask(&priv->mask, desc.len * BITS_PER_BYTE); + priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ; + priv->len = desc.len; + + return 0; +} + +static int nft_cmp16_fast_offload(struct nft_offload_ctx *ctx, + struct nft_flow_rule *flow, + const struct nft_expr *expr) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + struct nft_cmp_expr cmp = { + .data = priv->data, + .sreg = priv->sreg, + .len = priv->len, + .op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ, + }; + + return __nft_cmp_offload(ctx, flow, &cmp); +} + +static int nft_cmp16_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr); + enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ; + + if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) + goto nla_put_failure; + if (nla_put_be32(skb, NFTA_CMP_OP, htonl(op))) + goto nla_put_failure; + + if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, + NFT_DATA_VALUE, priv->len) < 0) + goto nla_put_failure; + return 0; + +nla_put_failure: + return -1; +} + + +const struct nft_expr_ops nft_cmp16_fast_ops = { + .type = &nft_cmp_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)), + .eval = NULL, /* inlined */ + .init = nft_cmp16_fast_init, + .dump = nft_cmp16_fast_dump, + .offload = nft_cmp16_fast_offload, +}; + static const struct nft_expr_ops * nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) { struct nft_data_desc desc; struct nft_data data; enum nft_cmp_ops op; + u8 sreg; int err;
if (tb[NFTA_CMP_SREG] == NULL || @@ -306,9 +397,16 @@ nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) if (desc.type != NFT_DATA_VALUE) goto err1;
- if (desc.len <= sizeof(u32) && (op == NFT_CMP_EQ || op == NFT_CMP_NEQ)) - return &nft_cmp_fast_ops; + sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG]));
+ if (op == NFT_CMP_EQ || op == NFT_CMP_NEQ) { + if (desc.len <= sizeof(u32)) + return &nft_cmp_fast_ops; + else if (desc.len <= sizeof(data) && + ((sreg >= NFT_REG_1 && sreg <= NFT_REG_4) || + (sreg >= NFT_REG32_00 && sreg <= NFT_REG32_12 && sreg % 2 == 0))) + return &nft_cmp16_fast_ops; + } return &nft_cmp_ops; err1: nft_data_release(&data, desc.type);