[PATCH 5.17 306/772] libbpf: Fix logic for finding matching program for CO-RE relocation

Greg Kroah-Hartman
2022-06-07T21:02:32Z

From: Andrii Nakryiko <andrii@kernel.org>

[ Upstream commit 966a7509325395c51c5f6d89e7352b0585e4804b ]

Fix the bug in bpf_object__relocate_core() which can lead to finding
invalid matching BPF program when processing CO-RE relocation. IF
matching program is not found, last encountered program will be assumed
to be correct program and thus error detection won't detect the problem.

Fixes: 9c82a63cf370 ("libbpf: Fix CO-RE relocs against .text section")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-4-andrii@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/lib/bpf/libbpf.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9c202bba911c..0ea7b91e675f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5639,9 +5639,10 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
*/
prog = NULL;
for (i = 0; i < obj->nr_programs; i++) {
- prog = &obj->programs[i];
- if (strcmp(prog->sec_name, sec_name) == 0)
+ if (strcmp(obj->programs[i].sec_name, sec_name) == 0) {
+ prog = &obj->programs[i];
break;
+ }
}
if (!prog) {
pr_warn("sec '%s': failed to find a BPF program\n", sec_name);
--
2.35.1