From 6728aea7216c0c06c98e2e58d753a5e8b2ae1c6f Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 15 Nov 2022 00:45:28 +0530 Subject: bpf: Refactor btf_struct_access Instead of having to pass multiple arguments that describe the register, pass the bpf_reg_state into the btf_struct_access callback. Currently, all call sites simply reuse the btf and btf_id of the reg they want to check the access of. The only exception to this pattern is the callsite in check_ptr_to_map_access, hence for that case create a dummy reg to simulate PTR_TO_BTF_ID access. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20221114191547.1694267-8-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- net/bpf/bpf_dummy_struct_ops.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'net/bpf') diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index e78dadfc5829..2d434c1f4617 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -156,29 +156,29 @@ static bool bpf_dummy_ops_is_valid_access(int off, int size, } static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, - const struct btf *btf, - const struct btf_type *t, int off, - int size, enum bpf_access_type atype, + const struct bpf_reg_state *reg, + int off, int size, enum bpf_access_type atype, u32 *next_btf_id, enum bpf_type_flag *flag) { const struct btf_type *state; + const struct btf_type *t; s32 type_id; int err; - type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state", + type_id = btf_find_by_name_kind(reg->btf, "bpf_dummy_ops_state", BTF_KIND_STRUCT); if (type_id < 0) return -EINVAL; - state = btf_type_by_id(btf, type_id); + t = btf_type_by_id(reg->btf, reg->btf_id); + state = btf_type_by_id(reg->btf, type_id); if (t != state) { bpf_log(log, "only access to bpf_dummy_ops_state is supported\n"); return -EACCES; } - err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id, - flag); + err = btf_struct_access(log, reg, off, size, atype, next_btf_id, flag); if (err < 0) return err; -- cgit v1.2.3 From 114039b342014680911c35bd6b72624180fd669a Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 21 Nov 2022 10:03:39 -0800 Subject: bpf: Move skb->len == 0 checks into __bpf_redirect To avoid potentially breaking existing users. Both mac/no-mac cases have to be amended; mac_header >= network_header is not enough (verified with a new test, see next patch). Fixes: fd1894224407 ("bpf: Don't redirect packets with invalid pkt_len") Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20221121180340.1983627-1-sdf@google.com Signed-off-by: Martin KaFai Lau --- net/bpf/test_run.c | 3 --- net/core/filter.c | 11 ++++++----- 2 files changed, 6 insertions(+), 8 deletions(-) (limited to 'net/bpf') diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 13d578ce2a09..6fba440efc40 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -979,9 +979,6 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb) { struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb; - if (!skb->len) - return -EINVAL; - if (!__skb) return 0; diff --git a/net/core/filter.c b/net/core/filter.c index 2a105fb1ceb2..b6e1b81cdfae 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2124,12 +2124,13 @@ static int __bpf_redirect_no_mac(struct sk_buff *skb, struct net_device *dev, { unsigned int mlen = skb_network_offset(skb); + if (unlikely(skb->len <= mlen)) { + kfree_skb(skb); + return -ERANGE; + } + if (mlen) { __skb_pull(skb, mlen); - if (unlikely(!skb->len)) { - kfree_skb(skb); - return -ERANGE; - } /* At ingress, the mac header has already been pulled once. * At egress, skb_pospull_rcsum has to be done in case that @@ -2149,7 +2150,7 @@ static int __bpf_redirect_common(struct sk_buff *skb, struct net_device *dev, u32 flags) { /* Verify that a link layer header is carried */ - if (unlikely(skb->mac_header >= skb->network_header)) { + if (unlikely(skb->mac_header >= skb->network_header || skb->len == 0)) { kfree_skb(skb); return -ERANGE; } -- cgit v1.2.3