This is a note to let you know that I've just added the patch titled
ACPI: custom_method: fix a possible memory leak
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-custom_method-fix-a-possible-memory-leak.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1cfd8956437f842836e8a066b40d1ec2fc01f13e Mon Sep 17 00:00:00 2001
From: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
Date: Tue, 27 Apr 2021 13:54:33 -0500
Subject: ACPI: custom_method: fix a possible memory leak
From: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
commit 1cfd8956437f842836e8a066b40d1ec2fc01f13e upstream.
In cm_write(), if the 'buf' is allocated memory but not fully consumed,
it is possible to reallocate the buffer without freeing it by passing
'*ppos' as 0 on a subsequent call.
Add an explicit kfree() before kzalloc() to prevent the possible memory
leak.
Fixes: 526b4af47f44 ("ACPI: Split out custom_method functionality into an own driver")
Signed-off-by: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
Cc: 5.4+ <stable@xxxxxxxxxxxxxxx> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/custom_method.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/acpi/custom_method.c
+++ b/drivers/acpi/custom_method.c
@@ -42,6 +42,8 @@ static ssize_t cm_write(struct file *fil
sizeof(struct acpi_table_header)))
return -EFAULT;
uncopied_bytes = max_size = table.length;
+ /* make sure the buf is not allocated */
+ kfree(buf);
buf = kzalloc(max_size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
Patches currently in stable-queue which might be from mlangsdo@xxxxxxxxxx are
queue-5.12/acpi-custom_method-fix-a-possible-memory-leak.patch
queue-5.12/acpi-custom_method-fix-potential-use-after-free-issue.patch
