diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/filter.c | 100 |
1 files changed, 83 insertions, 17 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 33310eee6134..4e9dd0ad0d5b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -150,10 +150,43 @@ static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5) return prandom_u32(); } +static u32 convert_skb_access(int skb_field, int dst_reg, int src_reg, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + + switch (skb_field) { + case SKF_AD_MARK: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); + + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, mark)); + break; + + case SKF_AD_PKTTYPE: + *insn++ = BPF_LDX_MEM(BPF_B, dst_reg, src_reg, PKT_TYPE_OFFSET()); + *insn++ = BPF_ALU32_IMM(BPF_AND, dst_reg, PKT_TYPE_MAX); +#ifdef __BIG_ENDIAN_BITFIELD + *insn++ = BPF_ALU32_IMM(BPF_RSH, dst_reg, 5); +#endif + break; + + case SKF_AD_QUEUE: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); + + *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, + offsetof(struct sk_buff, queue_mapping)); + break; + } + + return insn - insn_buf; +} + static bool convert_bpf_extensions(struct sock_filter *fp, struct bpf_insn **insnp) { struct bpf_insn *insn = *insnp; + u32 cnt; switch (fp->k) { case SKF_AD_OFF + SKF_AD_PROTOCOL: @@ -167,13 +200,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp, break; case SKF_AD_OFF + SKF_AD_PKTTYPE: - *insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX, - PKT_TYPE_OFFSET()); - *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX); -#ifdef __BIG_ENDIAN_BITFIELD - insn++; - *insn = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 5); -#endif + cnt = convert_skb_access(SKF_AD_PKTTYPE, BPF_REG_A, BPF_REG_CTX, insn); + insn += cnt - 1; break; case SKF_AD_OFF + SKF_AD_IFINDEX: @@ -197,10 +225,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp, break; case SKF_AD_OFF + SKF_AD_MARK: - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); - - *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, - offsetof(struct sk_buff, mark)); + cnt = convert_skb_access(SKF_AD_MARK, BPF_REG_A, BPF_REG_CTX, insn); + insn += cnt - 1; break; case SKF_AD_OFF + SKF_AD_RXHASH: @@ -211,10 +237,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp, break; case SKF_AD_OFF + SKF_AD_QUEUE: - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2); - - *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX, - offsetof(struct sk_buff, queue_mapping)); + cnt = convert_skb_access(SKF_AD_QUEUE, BPF_REG_A, BPF_REG_CTX, insn); + insn += cnt - 1; break; case SKF_AD_OFF + SKF_AD_VLAN_TAG: @@ -1151,13 +1175,55 @@ sk_filter_func_proto(enum bpf_func_id func_id) static bool sk_filter_is_valid_access(int off, int size, enum bpf_access_type type) { - /* skb fields cannot be accessed yet */ - return false; + /* only read is allowed */ + if (type != BPF_READ) + return false; + + /* check bounds */ + if (off < 0 || off >= sizeof(struct __sk_buff)) + return false; + + /* disallow misaligned access */ + if (off % size != 0) + return false; + + /* all __sk_buff fields are __u32 */ + if (size != 4) + return false; + + return true; +} + +static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + + switch (ctx_off) { + case offsetof(struct __sk_buff, len): + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); + + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, len)); + break; + + case offsetof(struct __sk_buff, mark): + return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn); + + case offsetof(struct __sk_buff, pkt_type): + return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn); + + case offsetof(struct __sk_buff, queue_mapping): + return convert_skb_access(SKF_AD_QUEUE, dst_reg, src_reg, insn); + } + + return insn - insn_buf; } static const struct bpf_verifier_ops sk_filter_ops = { .get_func_proto = sk_filter_func_proto, .is_valid_access = sk_filter_is_valid_access, + .convert_ctx_access = sk_filter_convert_ctx_access, }; static struct bpf_prog_type_list sk_filter_type __read_mostly = { |