| Message ID | 20220413062131.363740-2-liujian56@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Enlarge offset check value in bpf_skb_load_bytes | expand |
On 4/13/22 8:21 AM, Liu Jian wrote: > The data length of skb frags + frag_list may be greater than 0xffff, > and skb_header_pointer can not handle negative offset and negative len. > So here INT_MAX is used to check the validity of offset and len. > Add the same change to the related function skb_store_bytes. > > Fixes: 05c74e5e53f6 ("bpf: add bpf_skb_load_bytes helper") > Signed-off-by: Liu Jian <liujian56@huawei.com> > Acked-by: Song Liu <songliubraving@fb.com> > --- > v1->v2: change nothing, only add Acked-by tag > net/core/filter.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/core/filter.c b/net/core/filter.c > index 64470a727ef7..1571b6bc51ea 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -1687,7 +1687,7 @@ BPF_CALL_5(bpf_skb_store_bytes, struct sk_buff *, skb, u32, offset, > > if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM | BPF_F_INVALIDATE_HASH))) > return -EINVAL; > - if (unlikely(offset > 0xffff)) > + if (unlikely(offset > INT_MAX || len > INT_MAX)) > return -EFAULT; > if (unlikely(bpf_try_make_writable(skb, offset + len))) > return -EFAULT; > @@ -1722,7 +1722,7 @@ BPF_CALL_4(bpf_skb_load_bytes, const struct sk_buff *, skb, u32, offset, > { > void *ptr; > > - if (unlikely(offset > 0xffff)) > + if (unlikely(offset > INT_MAX || len > INT_MAX)) > goto err_clear; > > ptr = skb_header_pointer(skb, offset, len, to); > While at it, lets also change skb_ensure_writable()'s write_len param to unsigned int type. Both pskb_may_pull() and skb_clone_writable()'s length parameters are of type unsigned int already.
diff --git a/net/core/filter.c b/net/core/filter.c index 64470a727ef7..1571b6bc51ea 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1687,7 +1687,7 @@ BPF_CALL_5(bpf_skb_store_bytes, struct sk_buff *, skb, u32, offset, if (unlikely(flags & ~(BPF_F_RECOMPUTE_CSUM | BPF_F_INVALIDATE_HASH))) return -EINVAL; - if (unlikely(offset > 0xffff)) + if (unlikely(offset > INT_MAX || len > INT_MAX)) return -EFAULT; if (unlikely(bpf_try_make_writable(skb, offset + len))) return -EFAULT; @@ -1722,7 +1722,7 @@ BPF_CALL_4(bpf_skb_load_bytes, const struct sk_buff *, skb, u32, offset, { void *ptr; - if (unlikely(offset > 0xffff)) + if (unlikely(offset > INT_MAX || len > INT_MAX)) goto err_clear; ptr = skb_header_pointer(skb, offset, len, to);
The data length of skb frags + frag_list may be greater than 0xffff, and skb_header_pointer can not handle negative offset and negative len. So here INT_MAX is used to check the validity of offset and len. Add the same change to the related function skb_store_bytes. Fixes: 05c74e5e53f6 ("bpf: add bpf_skb_load_bytes helper") Signed-off-by: Liu Jian <liujian56@huawei.com> Acked-by: Song Liu <songliubraving@fb.com> --- v1->v2: change nothing, only add Acked-by tag net/core/filter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)