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Subject[PATCH 5.10 17/33] bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc
Date
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
@@ -92,7 +92,7 @@ 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]);
@@ -153,7 +153,7 @@ 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
@@ -52,7 +52,7 @@ 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)

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