linux-kernel - [PATCH v4] tpm: Return the actual size when receiving an unsupported command

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180622065000.31139-1-Ricardo.Schwarzmeier@infineon.com>
Date:   Fri, 22 Jun 2018 08:50:00 +0200
From:   Ricardo Schwarzmeier <Ricardo.Schwarzmeier@...ineon.com>
To:     <linux-integrity@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <peterhuewe@....de>,
        <jarkko.sakkinen@...ux.intel.com>, <jgg@...pe.ca>, <arnd@...db.de>,
        <gregkh@...uxfoundation.org>,
        Ricardo Schwarzmeier <Ricardo.Schwarzmeier@...ineon.com>
Subject: [PATCH v4] tpm: Return the actual size when receiving an unsupported command

The userpace expects to read the number of bytes stated in the header.
Returning the size of the buffer instead would be unexpected.
Fixes: 095531f891e6 ("tpm: return a TPM_RC_COMMAND_CODE response if command is not implemented")

Signed-off-by: Ricardo Schwarzmeier <Ricardo.Schwarzmeier@...ineon.com>
---
 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 e32f6e85dc6d..7f2e2d54894d 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)
-- 
2.17.1