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perf disasm: Fix potential use-after-free on fileloc

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The fileloc is a copy of a pointer to a string but in places like
symbol_disassemble__llvm this string appears to be freed setting up
potential use-after-frees:

llvm.c:
```
		dl = disasm_line__new(args);
		if (dl == NULL)
			goto err;

		annotation_line__add(&dl->al, &notes->src->source);

		free(args->fileloc);
```

disasm.c:
```
static void annotation_line__init(struct annotation_line *al,
				  struct annotate_args *args,
				  int nr)
{
	al->offset = args->offset;
	al->line = strdup(args->line);
	al->line_nr = args->line_nr;
	al->fileloc = args->fileloc;
	al->data_nr = nr;
}

struct disasm_line *disasm_line__new(struct annotate_args *args)
{
	struct disasm_line *dl = NULL;
	struct annotation *notes = symbol__annotation(args->ms->sym);
	int nr = notes->src->nr_events;

	dl = zalloc(disasm_line_size(nr));
	if (!dl)
		return NULL;

	annotation_line__init(&dl->al, args, nr);
```

Fix this by making the fileloc a copy of the underlying string in its
init/exit.

Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Ian Rogers 2026-03-06 16:22:22 -08:00 committed by Namhyung Kim
parent f182573e06
commit ad2f6258dd
1 changed files with 4 additions and 4 deletions
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8
tools/perf/util/disasm.c
View File

@ -908,13 +908,14 @@ static void annotation_line__init(struct annotation_line *al,
al->offset = args->offset;
al->line = strdup(args->line);
al->line_nr = args->line_nr;
al->fileloc = args->fileloc;
al->fileloc = args->fileloc ? strdup(args->fileloc) : NULL;
al->data_nr = nr;
}
static void annotation_line__exit(struct annotation_line *al)
{
zfree_srcline(&al->path);
zfree(&al->fileloc);
zfree(&al->line);
zfree(&al->cycles);
zfree(&al->br_cntr);
@ -950,7 +951,7 @@ struct disasm_line *disasm_line__new(struct annotate_args *args)
annotation_line__init(&dl->al, args, nr);
if (dl->al.line == NULL)
goto out_delete;
goto out_free_line;
if (args->offset != -1) {
if (arch__is_powerpc(args->arch)) {
@ -965,8 +966,7 @@ struct disasm_line *disasm_line__new(struct annotate_args *args)
return dl;
out_free_line:
zfree(&dl->al.line);
out_delete:
annotation_line__exit(&dl->al);
free(dl);
return NULL;
}