Leon Yu <chianglungyu@xxxxxxxxx> writes:
> If something went wrong in anon_inode_getfile, event_file will be set to
> non-zero error number and able to bypass the NULL test afterward.
>
> Consolidate the error path by testing event_file with handly
> IS_ERR_OR_NULL() helper since we do want to free event in both cases.
>
> Signed-off-by: Leon Yu <chianglungyu@xxxxxxxxx>
> Fixes: 130056275ade ("perf: Do not double free")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.5
> ---
> kernel/events/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 6146148..5f2e19f 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -8617,7 +8617,7 @@ err_alloc:
> * If event_file is set, the fput() above will have called ->release()
> * and that will take care of freeing the event.
> */
> - if (!event_file)
> + if (IS_ERR_OR_NULL(event_file))
> free_event(event);
By this time, we have already checked for IS_ERR(event_file) once, why
not just fix it up there like so:
---
From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Date: Mon, 21 Mar 2016 09:55:09 +0200
Subject: perf: Don't leak event in the syscall error path
In the error path, event_file not being NULL is used to determine
whether the event itself still needs to be free'd, so fix it up to avoid
leaking.
Reported-by: Leon Yu <chianglungyu@xxxxxxxxx>
Fixes: 130056275ade ("perf: Do not double free")
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
kernel/events/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ab83640a50..cc34d55f1e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9414,6 +9414,7 @@ SYSCALL_DEFINE5(perf_event_open,
f_flags);
if (IS_ERR(event_file)) {
err = PTR_ERR(event_file);
+ event_file = NULL;
goto err_context;
}
--
2.7.0
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