Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Alexei Starovoitov:

 - Finish constification of 1st parameter of bpf_d_path() (Rong Tao)

 - Harden userspace-supplied xdp_desc validation (Alexander Lobakin)

 - Fix metadata_dst leak in __bpf_redirect_neigh_v{4,6}() (Daniel
   Borkmann)

 - Fix undefined behavior in {get,put}_unaligned_be32() (Eric Biggers)

 - Use correct context to unpin bpf hash map with special types (KaFai
   Wan)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Add test for unpinning htab with internal timer struct
  bpf: Avoid RCU context warning when unpinning htab with internal structs
  xsk: Harden userspace-supplied xdp_desc validation
  bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6}
  libbpf: Fix undefined behavior in {get,put}_unaligned_be32()
  bpf: Finish constification of 1st parameter of bpf_d_path()

2 files changed, 37 insertions, 10 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index 5d1838ff1ab9..76628df1fc82 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2281,6 +2281,7 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
 		if (IS_ERR(dst))
 			goto out_drop;
 
+		skb_dst_drop(skb);
 		skb_dst_set(skb, dst);
 	} else if (nh->nh_family != AF_INET6) {
 		goto out_drop;
@@ -2389,6 +2390,7 @@ static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev,
 			goto out_drop;
 		}
 
+		skb_dst_drop(skb);
 		skb_dst_set(skb, &rt->dst);
 	}
 
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index f16f390370dc..1eb8d9f8b104 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -143,14 +143,24 @@ static inline bool xp_unused_options_set(u32 options)
 static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
 					    struct xdp_desc *desc)
 {
-	u64 addr = desc->addr - pool->tx_metadata_len;
-	u64 len = desc->len + pool->tx_metadata_len;
-	u64 offset = addr & (pool->chunk_size - 1);
+	u64 len = desc->len;
+	u64 addr, offset;
 
-	if (!desc->len)
+	if (!len)
 		return false;
 
-	if (offset + len > pool->chunk_size)
+	/* Can overflow if desc->addr < pool->tx_metadata_len */
+	if (check_sub_overflow(desc->addr, pool->tx_metadata_len, &addr))
+		return false;
+
+	offset = addr & (pool->chunk_size - 1);
+
+	/*
+	 * Can't overflow: @offset is guaranteed to be < ``U32_MAX``
+	 * (pool->chunk_size is ``u32``), @len is guaranteed
+	 * to be <= ``U32_MAX``.
+	 */
+	if (offset + len + pool->tx_metadata_len > pool->chunk_size)
 		return false;
 
 	if (addr >= pool->addrs_cnt)
@@ -158,27 +168,42 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
 
 	if (xp_unused_options_set(desc->options))
 		return false;
+
 	return true;
 }
 
 static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
 					      struct xdp_desc *desc)
 {
-	u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len;
-	u64 len = desc->len + pool->tx_metadata_len;
+	u64 len = desc->len;
+	u64 addr, end;
 
-	if (!desc->len)
+	if (!len)
 		return false;
 
+	/* Can't overflow: @len is guaranteed to be <= ``U32_MAX`` */
+	len += pool->tx_metadata_len;
 	if (len > pool->chunk_size)
 		return false;
 
-	if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
-	    xp_desc_crosses_non_contig_pg(pool, addr, len))
+	/* Can overflow if desc->addr is close to 0 */
+	if (check_sub_overflow(xp_unaligned_add_offset_to_addr(desc->addr),
+			       pool->tx_metadata_len, &addr))
+		return false;
+
+	if (addr >= pool->addrs_cnt)
+		return false;
+
+	/* Can overflow if pool->addrs_cnt is high enough */
+	if (check_add_overflow(addr, len, &end) || end > pool->addrs_cnt)
+		return false;
+
+	if (xp_desc_crosses_non_contig_pg(pool, addr, len))
 		return false;
 
 	if (xp_unused_options_set(desc->options))
 		return false;
+
 	return true;
 }