linux-kernel - [PATCH 3/6] tpm/tpm_i2c_stm_st33: Check return code of get

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

Message-Id: <1383413101-10975-3-git-send-email-peterhuewe@gmx.de>
Date:	Sat,  2 Nov 2013 18:24:58 +0100
From:	Peter Huewe <peterhuewe@....de>
To:	james.l.morris@...cle.com, tpmdd-devel@...ts.sourceforge.net,
	adlai@...ux.vnet.ibm.com
Cc:	linux-kernel@...r.kernel.org, Peter Huewe <PeterHuewe@....de>,
	stable@...r.kernel.org, Peter Huewe <peterhuewe@....de>
Subject: [PATCH 3/6] tpm/tpm_i2c_stm_st33: Check return code of get_burstcount

From: Peter Huewe <PeterHuewe@....de>

The 'get_burstcount' function can in some circumstances 'return -EBUSY' which
in tpm_stm_i2c_send is stored in an 'u32 burstcnt'
thus converting the signed value into an unsigned value, resulting
in 'burstcnt' being huge.
Changing the type to u32 only does not solve the problem as the signed
value is converted to an unsigned in I2C_WRITE_DATA, resulting in the
same effect.

Thus
-> Change type of burstcnt to u32 (the return type of get_burstcount)
-> Add a check for the return value of 'get_burstcount' and propagate a
potential error.

This makes also sense in the 'I2C_READ_DATA' case, where the there is no
signed/unsigned conversion.

found by coverity
Cc: stable@...r.kernel.org
Signed-off-by: Peter Huewe <peterhuewe@....de>
---
 drivers/char/tpm/tpm_i2c_stm_st33.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/char/tpm/tpm_i2c_stm_st33.c b/drivers/char/tpm/tpm_i2c_stm_st33.c
index a0d6ceb5..cf68403 100644
--- a/drivers/char/tpm/tpm_i2c_stm_st33.c
+++ b/drivers/char/tpm/tpm_i2c_stm_st33.c
@@ -410,6 +410,8 @@ static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 			     &chip->vendor.read_queue)
 	       == 0) {
 		burstcnt = get_burstcount(chip);
+		if (burstcnt < 0)
+			return burstcnt;
 		len = min_t(int, burstcnt, count - size);
 		I2C_READ_DATA(client, TPM_DATA_FIFO, buf + size, len);
 		size += len;
@@ -451,7 +453,8 @@ static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
 static int tpm_stm_i2c_send(struct tpm_chip *chip, unsigned char *buf,
 			    size_t len)
 {
-	u32 status, burstcnt = 0, i, size;
+	u32 status, i, size;
+	int burstcnt = 0;
 	int ret;
 	u8 data;
 	struct i2c_client *client;
@@ -482,6 +485,8 @@ static int tpm_stm_i2c_send(struct tpm_chip *chip, unsigned char *buf,
 
 	for (i = 0; i < len - 1;) {
 		burstcnt = get_burstcount(chip);
+		if (burstcnt < 0)
+			return burstcnt;
 		size = min_t(int, len - i - 1, burstcnt);
 		ret = I2C_WRITE_DATA(client, TPM_DATA_FIFO, buf, size);
 		if (ret < 0)
-- 
1.7.5.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/