libbpf: Fix realloc usage in bpf_core_find_cands

commit 35b9211c0a upstream.

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: ddc7c30426 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: William Smith <williampsmith@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200124201847.212528-1-andriin@fb.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrii Nakryiko 2020-01-24 12:18:46 -08:00 committed by Greg Kroah-Hartman
parent ab48c14a44
commit f7a2ccc00a
1 changed files with 3 additions and 1 deletions

View File

@ -2541,7 +2541,9 @@ 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;