Commit 1cfd8956 authored by Mark Langsdorf's avatar Mark Langsdorf Committed by Rafael J. Wysocki
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ACPI: custom_method: fix a possible memory leak 



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: 526b4af4 ("ACPI: Split out custom_method functionality into an own driver")
Signed-off-by: default avatarMark Langsdorf <mlangsdo@redhat.com>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e483bb9a

drivers/acpi/custom_method.c

+2 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ static ssize_t cm_write(struct file *file, const char __user *user_buf, 
				   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;