From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 13 Dec 2021 17:00:32 -0800
Subject: libbpf: Fix potential uninit memory read
Patch-mainline: v5.17-rc1
Git-commit: 4581e676d3be9d8c921a48bf18e92c5a8f31bf13
References: jsc#PED-1368

In case of BPF_CORE_TYPE_ID_LOCAL we fill out target result explicitly.
But targ_res itself isn't initialized in such a case, and subsequent
call to bpf_core_patch_insn() might read uninitialized field (like
fail_memsz_adjust in this case). So ensure that targ_res is
zero-initialized for BPF_CORE_TYPE_ID_LOCAL case.

This was reported by Coverity static analyzer.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211214010032.3843804-1-andrii@kernel.org
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/lib/bpf/relo_core.c |    1 +
 1 file changed, 1 insertion(+)

--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -1223,6 +1223,7 @@ int bpf_core_apply_relo_insn(const char
 	/* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
 	if (relo->kind == BPF_CORE_TYPE_ID_LOCAL) {
 		/* bpf_insn's imm value could get out of sync during linking */
+		memset(&targ_res, 0, sizeof(targ_res));
 		targ_res.validate = false;
 		targ_res.poison = false;
 		targ_res.orig_val = local_spec->root_type_id;