diff options
Diffstat (limited to 'net/core/filter.c')
| -rw-r--r-- | net/core/filter.c | 41 |
1 files changed, 32 insertions, 9 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index b669e75d2b36..bf831a85c315 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1175,12 +1175,27 @@ 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) { struct sk_buff *skb = (struct sk_buff *) (long) r1; - unsigned int offset = (unsigned int) r2; + int offset = (int) r2; void *from = (void *) (long) r3; unsigned int len = (unsigned int) r4; char buf[16]; @@ -1194,10 +1209,12 @@ static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags) * * so check for invalid 'offset' and too large 'len' */ - if (unlikely(offset > 0xffff || len > sizeof(buf))) + if (unlikely((u32) offset > 0xffff || len > sizeof(buf))) return -EFAULT; - if (skb_cloned(skb) && !skb_clone_writable(skb, offset + len)) + offset -= skb->data - skb_mac_header(skb); + if (unlikely(skb_cloned(skb) && + bpf_skb_clone_unwritable(skb, offset + len))) return -EFAULT; ptr = skb_header_pointer(skb, offset, len, buf); @@ -1232,15 +1249,18 @@ const struct bpf_func_proto bpf_skb_store_bytes_proto = { #define BPF_HEADER_FIELD_SIZE(flags) ((flags) & 0x0f) #define BPF_IS_PSEUDO_HEADER(flags) ((flags) & 0x10) -static u64 bpf_l3_csum_replace(u64 r1, u64 offset, u64 from, u64 to, u64 flags) +static u64 bpf_l3_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) { struct sk_buff *skb = (struct sk_buff *) (long) r1; + int offset = (int) r2; __sum16 sum, *ptr; - if (unlikely(offset > 0xffff)) + if (unlikely((u32) offset > 0xffff)) return -EFAULT; - if (skb_cloned(skb) && !skb_clone_writable(skb, offset + sizeof(sum))) + offset -= skb->data - skb_mac_header(skb); + if (unlikely(skb_cloned(skb) && + bpf_skb_clone_unwritable(skb, offset + sizeof(sum)))) return -EFAULT; ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); @@ -1276,16 +1296,19 @@ const struct bpf_func_proto bpf_l3_csum_replace_proto = { .arg5_type = ARG_ANYTHING, }; -static u64 bpf_l4_csum_replace(u64 r1, u64 offset, u64 from, u64 to, u64 flags) +static u64 bpf_l4_csum_replace(u64 r1, u64 r2, u64 from, u64 to, u64 flags) { struct sk_buff *skb = (struct sk_buff *) (long) r1; u32 is_pseudo = BPF_IS_PSEUDO_HEADER(flags); + int offset = (int) r2; __sum16 sum, *ptr; - if (unlikely(offset > 0xffff)) + if (unlikely((u32) offset > 0xffff)) return -EFAULT; - if (skb_cloned(skb) && !skb_clone_writable(skb, offset + sizeof(sum))) + offset -= skb->data - skb_mac_header(skb); + if (unlikely(skb_cloned(skb) && + bpf_skb_clone_unwritable(skb, offset + sizeof(sum)))) return -EFAULT; ptr = skb_header_pointer(skb, offset, sizeof(sum), &sum); |