bpf: Check for integer overflow when using roundup_pow_of_two()

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.

Bui Quang Minh committed 5 years ago

Commit 6183f4d1 parent 548f1191 file · +2 −0Browse files

Showing the changes to kernel/bpf/stackmap.c (1 of 1 file). Show all

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kernel/bpf/stackmap.c+2−0

@@ -115,6 +115,8 @@ static struct bpf_map stack_map_alloc(union bpf_attr attr) · 114 unmodified lines
115		115
116	/* hash table size must be power of 2 */	116	/* hash table size must be power of 2 */
117	n_buckets = roundup_pow_of_two(attr->max_entries);	117	n_buckets = roundup_pow_of_two(attr->max_entries);
		118	if (!n_buckets)
		119	return ERR_PTR(-E2BIG);
118		120
119	cost = n_buckets * sizeof(struct stack_map_bucket ) + sizeof(smap);	121	cost = n_buckets * sizeof(struct stack_map_bucket ) + sizeof(smap);
120	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));	122	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));