From: Andrii Nakryiko Date: Thu, 20 Feb 2025 00:28:21 +0000 (-0800) Subject: libbpf: Fix hypothetical STT_SECTION extern NULL deref case X-Git-Tag: v6.15-rc1~98^2~58 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e0525cd72b5979d8089fe524a071ea93fd011dc9;p=thirdparty%2Fkernel%2Flinux.git libbpf: Fix hypothetical STT_SECTION extern NULL deref case Fix theoretical NULL dereference in linker when resolving *extern* STT_SECTION symbol against not-yet-existing ELF section. Not sure if it's possible in practice for valid ELF object files (this would require embedded assembly manipulations, at which point BTF will be missing), but fix the s/dst_sym/dst_sec/ typo guarding this condition anyways. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20250220002821.834400-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index b52f71c59616f..800e0ef09c378 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -2163,7 +2163,7 @@ add_sym: obj->sym_map[src_sym_idx] = dst_sym_idx; - if (sym_type == STT_SECTION && dst_sym) { + if (sym_type == STT_SECTION && dst_sec) { dst_sec->sec_sym_idx = dst_sym_idx; dst_sym->st_value = 0; }