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 --- Hello,

This is for the 5.4 and 5.10 kernels.

Thanks, Connor

kernel/bpf/devmap.c | 4 ++-- net/core/sock_map.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 6684696fa457..4b2819b0a05a 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -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) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index df52061f99f7..2646e8f98f67 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -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)