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| author | Mark Langsdorf <mlangsdo@redhat.com> | 2021-04-27 21:54:33 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-22 11:59:12 +0300 |
| commit | 609e1328c8f571535882e51f3fce4e5c62c6a80d (patch) | |
| tree | 9bc391c15798f7ab63dd1f9531a2431f61f3bd31 | |
| parent | a5b26a2e362f572d87e9fd35435680e557052a17 (diff) | |
| download | linux-609e1328c8f571535882e51f3fce4e5c62c6a80d.tar.xz | |
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>
| -rw-r--r-- | drivers/acpi/custom_method.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index 0bc0be355571..613041870872 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -37,6 +37,8 @@ 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; |