5.15-stable review patch. If anyone has any objections, please let me know.
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From: Andrii Nakryiko andrii@kernel.org
[ Upstream commit e0525cd72b5979d8089fe524a071ea93fd011dc9 ]
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 andrii@kernel.org Link: https://lore.kernel.org/r/20250220002821.834400-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/linker.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 2adf55f487430..fc91814a35e8e 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -1966,7 +1966,7 @@ static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj,
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; }