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Message-Id: <20190305135246.180038284@goodmis.org>
Date: Tue, 05 Mar 2019 08:52:26 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
stable@...r.kernel.org, Masami Hiramatsu <mhiramat@...nel.org>,
Song Liu <songliubraving@...com>, Jann Horn <jannh@...gle.com>
Subject: [for-next][PATCH 3/6] tracing/perf: Use strndup_user() instead of buggy open-coded version
From: Jann Horn <jannh@...gle.com>
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@...nel.org>
Cc: stable@...r.kernel.org
Fixes: 0eadcc7a7bc0 ("perf/core: Fix perf_uprobe_init()")
Reviewed-by: Masami Hiramatsu <mhiramat@...nel.org>
Acked-by: Song Liu <songliubraving@...com>
Signed-off-by: Jann Horn <jannh@...gle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
kernel/trace/trace_event_perf.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 76217bbef815..4629a6104474 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -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;
--
2.20.1
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