From 35b9211c0a2427e8f39e534f442f43804fc8d5ca Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 24 Jan 2020 12:18:46 -0800 Subject: [PATCH] libbpf: Fix realloc usage in bpf_core_find_cands Fix bug requesting invalid size of reallocated array when constructing CO-RE relocation candidate list. This can cause problems if there are many potential candidates and a very fine-grained memory allocator bucket sizes are used. Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm") Reported-by: William Smith Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200124201847.212528-1-andriin@fb.com --- tools/lib/bpf/libbpf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 39f1b7633a7c..514b1a524abb 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3869,7 +3869,9 @@ static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf, if (strncmp(local_name, targ_name, local_essent_len) == 0) { pr_debug("[%d] %s: found candidate [%d] %s\n", local_type_id, local_name, i, targ_name); - new_ids = realloc(cand_ids->data, cand_ids->len + 1); + new_ids = reallocarray(cand_ids->data, + cand_ids->len + 1, + sizeof(*cand_ids->data)); if (!new_ids) { err = -ENOMEM; goto err_out;