[PATCH] bpf: Check for integer overflow when using roundup_pow_of_two()
From: Bui Quang Minh <hidden>
Date: 2021-01-27 06:44:41
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [tracing], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Song Liu, Linus Torvalds
On 32-bit architecture, roundup_pow_of_two() can return 0 when the argument
has upper most bit set due to resulting 1UL << 32. Add a check for this
case.
Fixes: d5a3b1f ("bpf: introduce BPF_MAP_TYPE_STACK_TRACE")
Signed-off-by: Bui Quang Minh <redacted>
---
kernel/bpf/stackmap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index aea96b638473..bfafbf115bf3 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c@@ -115,6 +115,8 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) /* hash table size must be power of 2 */ n_buckets = roundup_pow_of_two(attr->max_entries); + if (!n_buckets) + return ERR_PTR(-E2BIG); cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap); cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
--
2.17.1