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authorMark Langsdorf <mlangsdo@redhat.com>2021-04-27 13:54:33 -0500
committerDenys Drozdov <denys.drozdov@toradex.com>2021-07-15 13:52:46 +0300
commit0ff0002a8afc21767e9749b7d03a483e2159d8d4 (patch)
treeb034bdec8447d7fc9f4c71081f6167a4ad481d2f /drivers
parent4f895cc98b4286ee7732301900913fc9f2c5474b (diff)
ACPI: custom_method: fix a possible memory leak
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/acpi/custom_method.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c
index dfe097d07202..e7716c7b9be7 100644
--- a/drivers/acpi/custom_method.c
+++ b/drivers/acpi/custom_method.c
@@ -44,6 +44,8 @@ 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;