From 61ec14f42c844b7d011e0a939e522d577b2ed672 Mon Sep 17 00:00:00 2001 From: Ricardo Schwarzmeier Date: Tue, 26 Jun 2018 17:31:45 +0200 Subject: [PATCH] tpm: Return the actual size when receiving an unsupported command 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 Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman --- drivers/char/tpm/tpm-interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index dba5259def60..86b526b7d990 100644 --- 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 tpm_chip *chip, 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)