ACPI: custom_method: fix memory leaks

BugLink: https://bugs.launchpad.net/bugs/1847155
[ Upstream commit 03d1571d9513369c17e6848476763ebbd10ec2cb ]

In cm_write(), 'buf' is allocated through kzalloc(). In the following
execution, if an error occurs, 'buf' is not deallocated, leading to memory
leaks. To fix this issue, free 'buf' before returning the error.

Fixes: 526b4af47f44 ("ACPI: Split out custom_method functionality into an own driver")
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
index b33fba70ec51708a19fe59fc490b79f27f4de8f5..9dc745458739ad5d1aad29fb05d18fc3bd8c6e3d 100644 (file)
--- a/drivers/acpi/custom_method.c
+++ b/drivers/acpi/custom_method.c
@@ -51,8 +51,10 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf,
        if ((*ppos > max_size) ||
            (*ppos + count > max_size) ||
            (*ppos + count < count) ||
-           (count > uncopied_bytes))
+           (count > uncopied_bytes)) {
+               kfree(buf);
                return -EINVAL;
+       }
 
        if (copy_from_user(buf + (*ppos), user_buf, count)) {
                kfree(buf);
@@ -72,6 +74,7 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf,
                add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
        }
 
+       kfree(buf);
        return count;
 }