libbpf: Fix signedness bug in btf_dump_array_data()

BugLink: https://bugs.launchpad.net/bugs/1969110
[ Upstream commit 4172843ed4a38f97084032f74f07b2037b5da3a6 ]

The btf__resolve_size() function returns negative error codes so
"elem_size" must be signed for the error handling to work.

Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220208071552.GB10495@kili
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 855f1c64e21ed72f965ea30cdfaf8443b2ebfcf3)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 8c9325802793b316eae5c3335feeada61f453e3a..c1182dd94677427f170bb0af9235ead19292aab3 100644 (file)
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -1829,14 +1829,15 @@ static int btf_dump_array_data(struct btf_dump *d,
 {
        const struct btf_array *array = btf_array(t);
        const struct btf_type *elem_type;
-       __u32 i, elem_size = 0, elem_type_id;
+       __u32 i, elem_type_id;
+       __s64 elem_size;
        bool is_array_member;
 
        elem_type_id = array->type;
        elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
        elem_size = btf__resolve_size(d->btf, elem_type_id);
        if (elem_size <= 0) {
-               pr_warn("unexpected elem size %d for array type [%u]\n", elem_size, id);
+               pr_warn("unexpected elem size %lld for array type [%u]\n", elem_size, id);
                return -EINVAL;
        }