diff options
| author | Tim Gardner <tim.gardner@canonical.com> | 2011-12-06 11:29:20 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-02 09:52:37 -0700 |
| commit | 923da1e9e292633437c35fd870d47f18b0ee197f (patch) | |
| tree | bf4cbc80569796dcb80a890380f9b5e1f25a639d /drivers | |
| parent | c6cf24ba30c7225667827245cfd2bc98f7f5ed2b (diff) | |
TPM: Zero buffer whole after copying to userspace
commit 3ab1aff89477dafb1aaeafe8c8669114a02b7226 upstream.
Commit 3321c07ae5068568cd61ac9f4ba749006a7185c9 correctly clears the TPM
buffer if the user specified read length is >= the TPM buffer length. However,
if the user specified read length is < the TPM buffer length, then part of the
TPM buffer is left uncleared.
Reported-by: Seth Forshee <seth.forshee@canonical.com>
Cc: Debora Velarde <debora@linux.vnet.ibm.com>
Cc: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Cc: Marcel Selhorst <m.selhorst@sirrix.com>
Cc: tpmdd-devel@lists.sourceforge.net
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/char/tpm/tpm.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c index 361a1dff8f77..b366b34c8549 100644 --- a/drivers/char/tpm/tpm.c +++ b/drivers/char/tpm/tpm.c @@ -1115,12 +1115,13 @@ ssize_t tpm_read(struct file *file, char __user *buf, ret_size = atomic_read(&chip->data_pending); atomic_set(&chip->data_pending, 0); if (ret_size > 0) { /* relay data */ + ssize_t orig_ret_size = ret_size; if (size < ret_size) ret_size = size; mutex_lock(&chip->buffer_mutex); rc = copy_to_user(buf, chip->data_buffer, ret_size); - memset(chip->data_buffer, 0, ret_size); + memset(chip->data_buffer, 0, orig_ret_size); if (rc) ret_size = -EFAULT; |