diff options
Diffstat (limited to 'net/core/filter.c')
| -rw-r--r-- | net/core/filter.c | 261 |
1 files changed, 218 insertions, 43 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index bf831a85c315..be3098fb65e4 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -36,6 +36,7 @@ #include <net/netlink.h> #include <linux/skbuff.h> #include <net/sock.h> +#include <net/flow_dissector.h> #include <linux/errno.h> #include <linux/timer.h> #include <asm/uaccess.h> @@ -45,6 +46,7 @@ #include <linux/seccomp.h> #include <linux/if_vlan.h> #include <linux/bpf.h> +#include <net/sch_generic.h> /** * sk_filter - run a packet through a socket filter @@ -355,8 +357,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp, * for socket filters: ctx == 'struct sk_buff *', for seccomp: * ctx == 'struct seccomp_data *'. */ -int bpf_convert_filter(struct sock_filter *prog, int len, - struct bpf_insn *new_prog, int *new_len) +static int bpf_convert_filter(struct sock_filter *prog, int len, + struct bpf_insn *new_prog, int *new_len) { int new_flen = 0, pass = 0, target, i; struct bpf_insn *new_insn; @@ -371,7 +373,8 @@ int bpf_convert_filter(struct sock_filter *prog, int len, return -EINVAL; if (new_prog) { - addrs = kcalloc(len, sizeof(*addrs), GFP_KERNEL); + addrs = kcalloc(len, sizeof(*addrs), + GFP_KERNEL | __GFP_NOWARN); if (!addrs) return -ENOMEM; } @@ -751,7 +754,8 @@ static bool chk_code_allowed(u16 code_to_probe) * * Returns 0 if the rule set is legal or -EINVAL if not. */ -int bpf_check_classic(const struct sock_filter *filter, unsigned int flen) +static int bpf_check_classic(const struct sock_filter *filter, + unsigned int flen) { bool anc_found; int pc; @@ -825,7 +829,6 @@ int bpf_check_classic(const struct sock_filter *filter, unsigned int flen) return -EINVAL; } -EXPORT_SYMBOL(bpf_check_classic); static int bpf_prog_store_orig_filter(struct bpf_prog *fp, const struct sock_fprog *fprog) @@ -839,7 +842,9 @@ static int bpf_prog_store_orig_filter(struct bpf_prog *fp, fkprog = fp->orig_prog; fkprog->len = fprog->len; - fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL); + + fkprog->filter = kmemdup(fp->insns, fsize, + GFP_KERNEL | __GFP_NOWARN); if (!fkprog->filter) { kfree(fp->orig_prog); return -ENOMEM; @@ -941,7 +946,7 @@ static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp) * pass. At this time, the user BPF is stored in fp->insns. */ old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter), - GFP_KERNEL); + GFP_KERNEL | __GFP_NOWARN); if (!old_prog) { err = -ENOMEM; goto out_err; @@ -988,7 +993,8 @@ out_err: return ERR_PTR(err); } -static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp) +static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp, + bpf_aux_classic_check_t trans) { int err; @@ -1001,6 +1007,17 @@ static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp) return ERR_PTR(err); } + /* There might be additional checks and transformations + * needed on classic filters, f.e. in case of seccomp. + */ + if (trans) { + err = trans(fp->insns, fp->len); + if (err) { + __bpf_prog_release(fp); + return ERR_PTR(err); + } + } + /* Probe if we can JIT compile the filter and if so, do * the compilation of the filter. */ @@ -1050,7 +1067,7 @@ int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog) /* bpf_prepare_filter() already takes care of freeing * memory in case something goes wrong. */ - fp = bpf_prepare_filter(fp); + fp = bpf_prepare_filter(fp, NULL); if (IS_ERR(fp)) return PTR_ERR(fp); @@ -1059,6 +1076,53 @@ int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog) } EXPORT_SYMBOL_GPL(bpf_prog_create); +/** + * bpf_prog_create_from_user - create an unattached filter from user buffer + * @pfp: the unattached filter that is created + * @fprog: the filter program + * @trans: post-classic verifier transformation handler + * + * This function effectively does the same as bpf_prog_create(), only + * that it builds up its insns buffer from user space provided buffer. + * It also allows for passing a bpf_aux_classic_check_t handler. + */ +int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog, + bpf_aux_classic_check_t trans) +{ + unsigned int fsize = bpf_classic_proglen(fprog); + struct bpf_prog *fp; + + /* Make sure new filter is there and in the right amounts. */ + if (fprog->filter == NULL) + return -EINVAL; + + fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); + if (!fp) + return -ENOMEM; + + if (copy_from_user(fp->insns, fprog->filter, fsize)) { + __bpf_prog_free(fp); + return -EFAULT; + } + + fp->len = fprog->len; + /* Since unattached filters are not copied back to user + * space through sk_get_filter(), we do not need to hold + * a copy here, and can spare us the work. + */ + fp->orig_prog = NULL; + + /* bpf_prepare_filter() already takes care of freeing + * memory in case something goes wrong. + */ + fp = bpf_prepare_filter(fp, trans); + if (IS_ERR(fp)) + return PTR_ERR(fp); + + *pfp = fp; + return 0; +} + void bpf_prog_destroy(struct bpf_prog *fp) { __bpf_prog_release(fp); @@ -1135,7 +1199,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) /* bpf_prepare_filter() already takes care of freeing * memory in case something goes wrong. */ - prog = bpf_prepare_filter(prog); + prog = bpf_prepare_filter(prog, NULL); if (IS_ERR(prog)) return PTR_ERR(prog); @@ -1175,21 +1239,6 @@ int sk_attach_bpf(u32 ufd, struct sock *sk) return 0; } -/** - * bpf_skb_clone_not_writable - is the header of a clone not writable - * @skb: buffer to check - * @len: length up to which to write, can be negative - * - * Returns true if modifying the header part of the cloned buffer - * does require the data to be copied. I.e. this version works with - * negative lengths needed for eBPF case! - */ -static bool bpf_skb_clone_unwritable(const struct sk_buff *skb, int len) -{ - return skb_header_cloned(skb) || - (int) skb_headroom(skb) + len > skb->hdr_len; -} - #define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1) static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) @@ -1212,9 +1261,8 @@ static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) if (unlikely((u32) offset > 0xffff || len > sizeof(buf))) return -EFAULT; - offset -= skb->data - skb_mac_header(skb); if (unlikely(skb_cloned(skb) && - bpf_skb_clone_unwritable(skb, offset + len))) + !skb_clone_writable(skb, offset + len))) return -EFAULT; ptr = skb_header_pointer(skb, offset, len, buf); @@ -1258,9 +1306,8 @@ static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) if (unlikely((u32) offset > 0xffff)) return -EFAULT; - offset -= skb->data - skb_mac_header(skb); if (unlikely(skb_cloned(skb) && - bpf_skb_clone_unwritable(skb, offset + sizeof(sum)))) + !skb_clone_writable(skb, offset + sizeof(sum)))) return -EFAULT; ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); @@ -1306,9 +1353,8 @@ static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) if (unlikely((u32) offset > 0xffff)) return -EFAULT; - offset -= skb->data - skb_mac_header(skb); if (unlikely(skb_cloned(skb) && - bpf_skb_clone_unwritable(skb, offset + sizeof(sum)))) + !skb_clone_writable(skb, offset + sizeof(sum)))) return -EFAULT; ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); @@ -1344,6 +1390,40 @@ const struct bpf_func_proto bpf_l4_csum_replace_proto = { .arg5_type = ARG_ANYTHING, }; +#define BPF_IS_REDIRECT_INGRESS(flags) ((flags) & 1) + +static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5) +{ + struct sk_buff *skb = (struct sk_buff *) (long) r1, *skb2; + struct net_device *dev; + + dev = dev_get_by_index_rcu(dev_net(skb->dev), ifindex); + if (unlikely(!dev)) + return -EINVAL; + + if (unlikely(!(dev->flags & IFF_UP))) + return -EINVAL; + + skb2 = skb_clone(skb, GFP_ATOMIC); + if (unlikely(!skb2)) + return -ENOMEM; + + if (BPF_IS_REDIRECT_INGRESS(flags)) + return dev_forward_skb(dev, skb2); + + skb2->dev = dev; + return dev_queue_xmit(skb2); +} + +const struct bpf_func_proto bpf_clone_redirect_proto = { + .func = bpf_clone_redirect, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto * sk_filter_func_proto(enum bpf_func_id func_id) { @@ -1358,6 +1438,12 @@ sk_filter_func_proto(enum bpf_func_id func_id) return &bpf_get_prandom_u32_proto; case BPF_FUNC_get_smp_processor_id: return &bpf_get_smp_processor_id_proto; + case BPF_FUNC_tail_call: + return &bpf_tail_call_proto; + case BPF_FUNC_ktime_get_ns: + return &bpf_ktime_get_ns_proto; + case BPF_FUNC_trace_printk: + return bpf_get_trace_printk_proto(); default: return NULL; } @@ -1373,18 +1459,15 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) return &bpf_l3_csum_replace_proto; case BPF_FUNC_l4_csum_replace: return &bpf_l4_csum_replace_proto; + case BPF_FUNC_clone_redirect: + return &bpf_clone_redirect_proto; default: return sk_filter_func_proto(func_id); } } -static bool sk_filter_is_valid_access(int off, int size, - enum bpf_access_type type) +static bool __is_valid_access(int off, int size, enum bpf_access_type type) { - /* only read is allowed */ - if (type != BPF_READ) - return false; - /* check bounds */ if (off < 0 || off >= sizeof(struct __sk_buff)) return false; @@ -1400,8 +1483,42 @@ static bool sk_filter_is_valid_access(int off, int size, return true; } -static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, - struct bpf_insn *insn_buf) +static bool sk_filter_is_valid_access(int off, int size, + enum bpf_access_type type) +{ + if (type == BPF_WRITE) { + switch (off) { + case offsetof(struct __sk_buff, cb[0]) ... + offsetof(struct __sk_buff, cb[4]): + break; + default: + return false; + } + } + + return __is_valid_access(off, size, type); +} + +static bool tc_cls_act_is_valid_access(int off, int size, + enum bpf_access_type type) +{ + if (type == BPF_WRITE) { + switch (off) { + case offsetof(struct __sk_buff, mark): + case offsetof(struct __sk_buff, tc_index): + case offsetof(struct __sk_buff, cb[0]) ... + offsetof(struct __sk_buff, cb[4]): + break; + default: + return false; + } + } + return __is_valid_access(off, size, type); +} + +static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, + int src_reg, int ctx_off, + struct bpf_insn *insn_buf) { struct bpf_insn *insn = insn_buf; @@ -1434,8 +1551,34 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, offsetof(struct sk_buff, priority)); break; + case offsetof(struct __sk_buff, ingress_ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4); + + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, skb_iif)); + break; + + case offsetof(struct __sk_buff, ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); + + *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), + dst_reg, src_reg, + offsetof(struct sk_buff, dev)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1); + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg, + offsetof(struct net_device, ifindex)); + break; + case offsetof(struct __sk_buff, mark): - return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn); + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); + + if (type == BPF_WRITE) + *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, mark)); + else + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, mark)); + break; case offsetof(struct __sk_buff, pkt_type): return convert_skb_access(SKF_AD_PKTTYPE, dst_reg, src_reg, insn); @@ -1450,6 +1593,38 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, case offsetof(struct __sk_buff, vlan_tci): return convert_skb_access(SKF_AD_VLAN_TAG, dst_reg, src_reg, insn); + + case offsetof(struct __sk_buff, cb[0]) ... + offsetof(struct __sk_buff, cb[4]): + BUILD_BUG_ON(FIELD_SIZEOF(struct qdisc_skb_cb, data) < 20); + + ctx_off -= offsetof(struct __sk_buff, cb[0]); + ctx_off += offsetof(struct sk_buff, cb); + ctx_off += offsetof(struct qdisc_skb_cb, data); + if (type == BPF_WRITE) + *insn++ = BPF_STX_MEM(BPF_W, dst_reg, src_reg, ctx_off); + else + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, ctx_off); + break; + + case offsetof(struct __sk_buff, tc_index): +#ifdef CONFIG_NET_SCHED + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, tc_index) != 2); + + if (type == BPF_WRITE) + *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, + offsetof(struct sk_buff, tc_index)); + else + *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, + offsetof(struct sk_buff, tc_index)); + break; +#else + if (type == BPF_WRITE) + *insn++ = BPF_MOV64_REG(dst_reg, dst_reg); + else + *insn++ = BPF_MOV64_IMM(dst_reg, 0); + break; +#endif } return insn - insn_buf; @@ -1458,13 +1633,13 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, 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, + .convert_ctx_access = bpf_net_convert_ctx_access, }; static const struct bpf_verifier_ops tc_cls_act_ops = { .get_func_proto = tc_cls_act_func_proto, - .is_valid_access = sk_filter_is_valid_access, - .convert_ctx_access = sk_filter_convert_ctx_access, + .is_valid_access = tc_cls_act_is_valid_access, + .convert_ctx_access = bpf_net_convert_ctx_access, }; static struct bpf_prog_type_list sk_filter_type __read_mostly = { |