[PATCH 6.1.y 2/2] netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

[XiaoHua Wang <561399680@139.com>]

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 4c5c6aa9967dbe55bd017bb509885928d0f31206 ]

When calculating the lookup table size, ensure the following
multiplication does not overflow:

- desc->field_len[] maximum value is U8_MAX multiplied by
  NFT_PIPAPO_GROUPS_PER_BYTE(f) that can be 2, worst case.
- NFT_PIPAPO_BUCKETS(f->bb) is 2^8, worst case.
- sizeof(unsigned long), from sizeof(*f->lt), lt in
  struct nft_pipapo_field.

Then, use check_mul_overflow() to multiply by bucket size and then use
check_add_overflow() to the alignment for avx2 (if needed). Finally, add
lt_size_check_overflow() helper and use it to consolidate this.

While at it, replace leftover allocation using the GFP_KERNEL to
GFP_KERNEL_ACCOUNT for consistency, in pipapo_resize().

Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[ Adjust context ]
Signed-off-by: XiaoHua Wang <561399680@139.com>
---
 net/netfilter/nft_set_pipapo.c | 58 ++++++++++++++++++++++++++--------
 1 file changed, 44 insertions(+), 14 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index ad9d0bb43248..c90fb381bf7a 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -610,6 +610,30 @@ static void *nft_pipapo_get(const struct net *net, const struct nft_set *set,
 			 nft_genmask_cur(net), get_jiffies_64());
 }
 
+
+/**
+ * lt_calculate_size() - Get storage size for lookup table with overflow check
+ * @groups:	Amount of bit groups
+ * @bb:		Number of bits grouped together in lookup table buckets
+ * @bsize:	Size of each bucket in lookup table, in longs
+ *
+ * Return: allocation size including alignment overhead, negative on overflow
+ */
+static ssize_t lt_calculate_size(unsigned int groups, unsigned int bb,
+				 unsigned int bsize)
+{
+	ssize_t ret = groups * NFT_PIPAPO_BUCKETS(bb) * sizeof(long);
+
+	if (check_mul_overflow(ret, bsize, &ret))
+		return -1;
+	if (check_add_overflow(ret, NFT_PIPAPO_ALIGN_HEADROOM, &ret))
+		return -1;
+	if (ret > INT_MAX)
+		return -1;
+
+	return ret;
+}
+
 /**
  * pipapo_resize() - Resize lookup or mapping table, or both
  * @f:		Field containing lookup and mapping tables
@@ -628,6 +652,7 @@ static int pipapo_resize(struct nft_pipapo_field *f, int old_rules, int rules)
 	union nft_pipapo_map_bucket *new_mt, *old_mt = f->mt;
 	size_t new_bucket_size, copy;
 	int group, bucket;
+	ssize_t lt_size;
 
 	new_bucket_size = DIV_ROUND_UP(rules, BITS_PER_LONG);
 #ifdef NFT_PIPAPO_ALIGN
@@ -643,10 +668,11 @@ static int pipapo_resize(struct nft_pipapo_field *f, int old_rules, int rules)
 	else
 		copy = new_bucket_size;
 
-	new_lt = kvzalloc(f->groups * NFT_PIPAPO_BUCKETS(f->bb) *
-			  new_bucket_size * sizeof(*new_lt) +
-			  NFT_PIPAPO_ALIGN_HEADROOM,
-			  GFP_KERNEL);
+	lt_size = lt_calculate_size(f->groups, f->bb, new_bucket_size);
+	if (lt_size < 0)
+		return -ENOMEM;
+
+	new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT);
 	if (!new_lt)
 		return -ENOMEM;
 
@@ -845,7 +871,7 @@ static void pipapo_lt_bits_adjust(struct nft_pipapo_field *f)
 {
 	unsigned long *new_lt;
 	int groups, bb;
-	size_t lt_size;
+	ssize_t lt_size;
 
 	lt_size = f->groups * NFT_PIPAPO_BUCKETS(f->bb) * f->bsize *
 		  sizeof(*f->lt);
@@ -855,15 +881,17 @@ static void pipapo_lt_bits_adjust(struct nft_pipapo_field *f)
 		groups = f->groups * 2;
 		bb = NFT_PIPAPO_GROUP_BITS_LARGE_SET;
 
-		lt_size = groups * NFT_PIPAPO_BUCKETS(bb) * f->bsize *
-			  sizeof(*f->lt);
+		lt_size = lt_calculate_size(groups, bb, f->bsize);
+		if (lt_size < 0)
+			return;
 	} else if (f->bb == NFT_PIPAPO_GROUP_BITS_LARGE_SET &&
 		   lt_size < NFT_PIPAPO_LT_SIZE_LOW) {
 		groups = f->groups / 2;
 		bb = NFT_PIPAPO_GROUP_BITS_SMALL_SET;
 
-		lt_size = groups * NFT_PIPAPO_BUCKETS(bb) * f->bsize *
-			  sizeof(*f->lt);
+		lt_size = lt_calculate_size(groups, bb, f->bsize);
+		if (lt_size < 0)
+			return;
 
 		/* Don't increase group width if the resulting lookup table size
 		 * would exceed the upper size threshold for a "small" set.
@@ -874,7 +902,7 @@ static void pipapo_lt_bits_adjust(struct nft_pipapo_field *f)
 		return;
 	}
 
-	new_lt = kvzalloc(lt_size + NFT_PIPAPO_ALIGN_HEADROOM, GFP_KERNEL_ACCOUNT);
+	new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT);
 	if (!new_lt)
 		return;
 
@@ -1348,13 +1376,15 @@ static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old)
 
 	for (i = 0; i < old->field_count; i++) {
 		unsigned long *new_lt;
+		ssize_t lt_size;
 
 		memcpy(dst, src, offsetof(struct nft_pipapo_field, lt));
 
-		new_lt = kvzalloc(src->groups * NFT_PIPAPO_BUCKETS(src->bb) *
-				  src->bsize * sizeof(*dst->lt) +
-				  NFT_PIPAPO_ALIGN_HEADROOM,
-				  GFP_KERNEL_ACCOUNT);
+		lt_size = lt_calculate_size(src->groups, src->bb, src->bsize);
+		if (lt_size < 0)
+			goto out_lt;
+
+		new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT);
 		if (!new_lt)
 			goto out_lt;
 
-- 
2.43.0