From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bui Quang Minh <minhquangbui99@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Connor OBrien <connoro@google.com>
Subject: [PATCH 5.4 12/18] bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc
Date:   Wed, 15 Dec 2021 18:21:33 +0100
Message-Id: <20211215172023.233762350@linuxfoundation.org>
In-Reply-To: <20211215172022.795825673@linuxfoundation.org>
References: <20211215172022.795825673@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Bui Quang Minh <minhquangbui99@gmail.com>

commit 7dd5d437c258bbf4cc15b35229e5208b87b8b4e0 upstream.

In 32-bit architecture, the result of sizeof() is a 32-bit integer so
the expression becomes the multiplication between 2 32-bit integer which
can potentially leads to integer overflow. As a result,
bpf_map_area_alloc() allocates less memory than needed.

Fix this by casting 1 operand to u64.

Fixes: 0d2c4f964050 ("bpf: Eliminate rlimit-based memory accounting for sockmap and sockhash maps")
Fixes: 99c51064fb06 ("devmap: Use bpf_map_area_alloc() for allocating hash buckets")
Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210613143440.71975-1-minhquangbui99@gmail.com
Signed-off-by: Connor O'Brien <connoro@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/bpf/devmap.c |    4 ++--
 net/core/sock_map.c |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -94,7 +94,7 @@ static struct hlist_head *dev_map_create
 	int i;
 	struct hlist_head *hash;
 
-	hash = bpf_map_area_alloc(entries * sizeof(*hash), numa_node);
+	hash = bpf_map_area_alloc((u64) entries * sizeof(*hash), numa_node);
 	if (hash != NULL)
 		for (i = 0; i < entries; i++)
 			INIT_HLIST_HEAD(&hash[i]);
@@ -159,7 +159,7 @@ static int dev_map_init_map(struct bpf_d
 
 		spin_lock_init(&dtab->index_lock);
 	} else {
-		dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries *
+		dtab->netdev_map = bpf_map_area_alloc((u64) dtab->map.max_entries *
 						      sizeof(struct bpf_dtab_netdev *),
 						      dtab->map.numa_node);
 		if (!dtab->netdev_map)
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -48,7 +48,7 @@ static struct bpf_map *sock_map_alloc(un
 	if (err)
 		goto free_stab;
 
-	stab->sks = bpf_map_area_alloc(stab->map.max_entries *
+	stab->sks = bpf_map_area_alloc((u64) stab->map.max_entries *
 				       sizeof(struct sock *),
 				       stab->map.numa_node);
 	if (stab->sks)