| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 050/165] TPM: Zero buffer after copying to userspace | Date | Wed, 15 Aug 2012 15:46:34 -0400 |
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From: Peter Huewe <huewe.external.infineon@googlemail.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
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: Paul Gortmaker <paul.gortmaker@windriver.com> --- drivers/char/tpm/tpm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c index f39e5ee..9fe4683 100644 --- a/drivers/char/tpm/tpm.c +++ b/drivers/char/tpm/tpm.c @@ -1031,6 +1031,7 @@ 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(); @@ -1041,8 +1042,11 @@ 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); } -- 1.7.12.rc2
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