[3.8.y.z extended stable] Patch "tpm/tpm_ppi: Do not compare strcmp(a, b) == -1" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 3cdabfda568e42d8e470980979c209c69d7fbeeb Mon Sep 17 00:00:00 2001
From: Peter Huewe <PeterHuewe at gmx.de>
Date: Wed, 30 Oct 2013 20:46:55 +0100
Subject: tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

commit 747d35bd9bb4ae6bd74b19baa5bbe32f3e0cee11 upstream.

Depending on the implementation strcmp might return the difference between
two strings not only -1,0,1 consequently
 if (strcmp (a,b) == -1)
might lead to taking the wrong branch

-> compare with < 0  instead,
which in any case is more canonical.

Signed-off-by: Peter Huewe <peterhuewe at gmx.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/char/tpm/tpm_ppi.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index d0f1bdd..1900b4b 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -172,7 +172,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
 	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
 	 * version 1.1
 	 */
-	if (strcmp(version, "1.1") == -1)
+	if (strcmp(version, "1.1") < 0)
 		params[2].integer.value = TPM_PPI_FN_SUBREQ;
 	else
 		params[2].integer.value = TPM_PPI_FN_SUBREQ2;
@@ -182,7 +182,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
 	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
 	 * for compatibility, and use package type since 1.2 according to spec.
 	 */
-	if (strcmp(version, "1.2") == -1) {
+	if (strcmp(version, "1.2") < 0) {
 		params[3].type = ACPI_TYPE_BUFFER;
 		params[3].buffer.length = sizeof(req);
 		sscanf(buf, "%d", &req);
@@ -248,7 +248,7 @@ static ssize_t tpm_show_ppi_transition_action(struct device *dev,
 	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
 	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
 	 */
-	if (strcmp(version, "1.2") == -1) {
+	if (strcmp(version, "1.2") < 0) {
 		params[3].type = ACPI_TYPE_BUFFER;
 		params[3].buffer.length =  0;
 		params[3].buffer.pointer = NULL;
@@ -390,7 +390,7 @@ static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
 	kfree(output.pointer);
 	output.length = ACPI_ALLOCATE_BUFFER;
 	output.pointer = NULL;
-	if (strcmp(version, "1.2") == -1)
+	if (strcmp(version, "1.2") < 0)
 		return -EPERM;

 	params[2].integer.value = TPM_PPI_FN_GETOPR;
--
1.8.3.2