Commit f6f1d191 authored Jun 13, 2021 by Bui Quang Minh Committed by Greg Kroah-Hartman Dec 17, 2021

bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc

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: 546ac1ff ("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>

parent b06b1f46

kernel/bpf/devmap.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -94,7 +94,7 @@ static struct hlist_head *dev_map_create_hash(unsigned int entries,
		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_dtab dtab, union bpf_attr attr)

		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)

+1 −1

Original line number	Diff line number	Diff line
		@@ -48,7 +48,7 @@ static struct bpf_map sock_map_alloc(union bpf_attr attr)
		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)