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From: Alexander Steffen <Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
To: jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
	tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: [PATCH RESEND 2/2] tpm-interface: Fix checks of buffer size
Date: Thu, 24 Aug 2017 10:35:45 +0200	[thread overview]
Message-ID: <20170824083545.13280-3-Alexander.Steffen@infineon.com> (raw)
In-Reply-To: <20170824083545.13280-1-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>

bufsiz contains the length of the buffer, whereas bufvalid contains the
number of valid bytes within the buffer. Therefore, bufvalid should be used
as a limit when reading from the buffer and bufsize when writing to it.

Signed-off-by: Alexander Steffen <Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
---
 drivers/char/tpm/tpm-interface.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 78fb41d..f481cd1 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -393,19 +393,16 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	unsigned long stop;
 	bool need_locality;
 
-	if (!tpm_validate_command(chip, space, buf, bufsiz))
+	if (!tpm_validate_command(chip, space, buf, bufvalid))
 		return -EINVAL;
 
-	if (bufsiz > TPM_BUFSIZE)
-		bufsiz = TPM_BUFSIZE;
-
 	count = be32_to_cpu(*((__be32 *) (buf + 2)));
 	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 	if (count == 0)
 		return -ENODATA;
-	if (count > bufsiz || count > bufvalid) {
+	if (count > bufvalid) {
 		dev_err(&chip->dev,
-			"invalid count value %x %zx\n", count, bufsiz);
+			"invalid count value %x %zx\n", count, bufvalid);
 		return -E2BIG;
 	}
 
-- 
2.7.4


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  parent reply	other threads:[~2017-08-24  8:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-24  8:35 [PATCH RESEND 0/2] Avoid sending invalid data to the TPM Alexander Steffen
     [not found] ` <20170824083545.13280-1-Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w@public.gmane.org>
2017-08-24  8:35   ` [PATCH RESEND 1/2] tpm-dev-common: Reject too short writes Alexander Steffen
2017-08-25 16:54     ` Jarkko Sakkinen
     [not found]       ` <20170825165451.b7lv7t5w3nhbz7da-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-08-28 17:11         ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w
2017-08-30 10:40           ` Jarkko Sakkinen
2017-09-04 17:35             ` Alexander.Steffen
     [not found]               ` <dd865ba5751e4d568709e0aaf209633b-nFblLGNE8XKJSz+rYg/bSJowlv4uC7bZ@public.gmane.org>
2017-09-05 19:02                 ` Jarkko Sakkinen
2017-08-24  8:35   ` Alexander Steffen [this message]
2017-08-25 16:44   ` [PATCH RESEND 0/2] Avoid sending invalid data to the TPM Jarkko Sakkinen
     [not found]     ` <20170825164416.svo7khm4zsmosxbx-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-09-01 12:08       ` Alexander.Steffen-d0qZbvYSIPpWk0Htik3J/w

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