]> git.hungrycats.org Git - linux/commitdiff
TPM: Zero buffer after copying to userspace
authorPeter Huewe <huewe.external.infineon@googlemail.com>
Thu, 15 Sep 2011 17:47:42 +0000 (14:47 -0300)
committerGreg Kroah-Hartman <gregkh@suse.de>
Mon, 7 Nov 2011 21:47:00 +0000 (13:47 -0800)
commit 3321c07ae5068568cd61ac9f4ba749006a7185c9 upstream.

Since the buffer might contain security related data it might be a good idea to
zero the buffer after we have copied it to userspace.

This got assigned CVE-2011-1162.

Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/char/tpm/tpm.c

index 59078c1844decff70aaf72ce298da35d554de3cf..6fc23329f3d9d054e7b413041a48491c4baf8679 100644 (file)
@@ -1030,6 +1030,7 @@ ssize_t tpm_read(struct file *file, char __user *buf,
 {
        struct tpm_chip *chip = file->private_data;
        ssize_t ret_size;
+       int rc;
 
        del_singleshot_timer_sync(&chip->user_read_timer);
        flush_scheduled_work();
@@ -1040,8 +1041,11 @@ ssize_t tpm_read(struct file *file, char __user *buf,
                        ret_size = size;
 
                mutex_lock(&chip->buffer_mutex);
-               if (copy_to_user(buf, chip->data_buffer, ret_size))
+               rc = copy_to_user(buf, chip->data_buffer, ret_size);
+               memset(chip->data_buffer, 0, ret_size);
+               if (rc)
                        ret_size = -EFAULT;
+
                mutex_unlock(&chip->buffer_mutex);
        }