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tracing/perf: Use strndup_user() instead of buggy open-coded version 

The first version of this method was missing the check for
`ret == PATH_MAX`; then such a check was added, but it didn't call kfree()
on error, so there was still a small memory leak in the error case.
Fix it by using strndup_user() instead of open-coding it.

Link: http://lkml.kernel.org/r/20190220165443.152385-1-jannh@google.com

Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 0eadcc7a7b ("perf/core: Fix perf_uprobe_init()")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Jann Horn 2019-02-20 17:54:43 +01:00 committed by Steven Rostedt (VMware)
parent b689269bd1
commit 83540fbc88
1 changed files with 7 additions and 9 deletions
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16
kernel/trace/trace_event_perf.c
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@ -299,15 +299,13 @@ int perf_uprobe_init(struct perf_event *p_event,
if (!p_event->attr.uprobe_path)
return -EINVAL;
path = kzalloc(PATH_MAX, GFP_KERNEL);
if (!path)
return -ENOMEM;
ret = strncpy_from_user(
path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
if (ret == PATH_MAX)
return -E2BIG;
if (ret < 0)
goto out;
path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
PATH_MAX);
if (IS_ERR(path)) {
ret = PTR_ERR(path);
return (ret == -EINVAL) ? -E2BIG : ret;
}
if (path[0] == '\0') {
ret = -EINVAL;
goto out;