| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.12 017/384] ACPI: custom_method: fix a possible memory leak | Date | Mon, 10 May 2021 12:16:46 +0200 |
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From: Mark Langsdorf <mlangsdo@redhat.com>
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@redhat.com> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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;
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