4.18-stable review patch. If anyone has any objections, please let me know.
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From: Ricardo Schwarzmeier Ricardo.Schwarzmeier@infineon.com
commit 36a11029b07ee30bdc4553274d0efea645ed9d91 upstream.
The userpace expects to read the number of bytes stated in the header. Returning the size of the buffer instead would be unexpected.
Cc: stable@vger.kernel.org Fixes: 095531f891e6 ("tpm: return a TPM_RC_COMMAND_CODE response if command is not implemented") Signed-off-by: Ricardo Schwarzmeier Ricardo.Schwarzmeier@infineon.com Reviewed-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/char/tpm/tpm-interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -423,7 +423,7 @@ static ssize_t tpm_try_transmit(struct t header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE | TSS2_RESMGR_TPM_RC_LAYER); - return bufsiz; + return sizeof(*header); }
if (bufsiz > TPM_BUFSIZE)