objtool/klp: Fix cloning of zero-length section symbols

Fix NULL dereference when cloning a symbol from an empty section.
sec->data is only populated for sections with non-zero size.

Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index a226e99948b397027f62f152e57d3260858a354f..17a6146b9406bac414e84a33b5822d46efeac8ae 100644 (file)
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -681,7 +681,7 @@ static struct symbol *__clone_symbol(struct elf *elf, struct symbol *patched_sym
                        size_t size;
 
                        /* bss doesn't have data */
-                       if (patched_sym->sec->data->d_buf)
+                       if (patched_sym->sec->data && patched_sym->sec->data->d_buf)
                                data = patched_sym->sec->data->d_buf + patched_sym->offset;
 
                        if (is_sec_sym(patched_sym))