From 1cfd8956437f842836e8a066b40d1ec2fc01f13e Mon Sep 17 00:00:00 2001 From: Mark Langsdorf Date: Tue, 27 Apr 2021 13:54:33 -0500 Subject: 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: 526b4af47f44 ("ACPI: Split out custom_method functionality into an own driver") Signed-off-by: Mark Langsdorf Cc: 5.4+ # 5.4+ Signed-off-by: Rafael J. Wysocki --- drivers/acpi/custom_method.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/acpi/custom_method.c') diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index 8844f895f9be..d39a9b474727 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -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; -- cgit v1.2.3