| Date | Wed, 02 Nov 2011 15:14:02 -0700 | From | Greg KH <> | Subject | [036/107] TPM: Zero buffer after copying to userspace |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: Peter Huewe <huewe.external.infineon@googlemail.com>
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 | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/char/tpm/tpm.c +++ b/drivers/char/tpm/tpm.c @@ -1044,6 +1044,7 @@ ssize_t tpm_read(struct file *file, char { struct tpm_chip *chip = file->private_data; ssize_t ret_size; + int rc; del_singleshot_timer_sync(&chip->user_read_timer); flush_scheduled_work(); @@ -1054,8 +1055,11 @@ ssize_t tpm_read(struct file *file, char 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); }
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