[PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

From: Peter Huewe
Date: Tue Oct 29 2013 - 20:37:11 EST


strcmp does 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 <= instead.

This also makes the code/behavior compliant with its comments.
(e.g. if PPI Version is 1.0)

Fixes Coverity complaints:
CID: 741083 Misuse of memcmp-style function
CID: 741084 Misuse of memcmp-style function
CID: 741085 Misuse of memcmp-style function

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Peter Huewe <peterhuewe@xxxxxx>
---
drivers/char/tpm/tpm_ppi.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
index 8e562dc..8b2e05a 100644
--- a/drivers/char/tpm/tpm_ppi.c
+++ b/drivers/char/tpm/tpm_ppi.c
@@ -169,7 +169,7 @@ 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") <= -1)
params[2].integer.value = TPM_PPI_FN_SUBREQ;
else
params[2].integer.value = TPM_PPI_FN_SUBREQ2;
@@ -179,7 +179,7 @@ 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") <= -1) {
params[3].type = ACPI_TYPE_BUFFER;
params[3].buffer.length = sizeof(req);
sscanf(buf, "%d", &req);
@@ -245,7 +245,7 @@ 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") <= -1) {
params[3].type = ACPI_TYPE_BUFFER;
params[3].buffer.length = 0;
params[3].buffer.pointer = NULL;
@@ -387,7 +387,7 @@ 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") <= -1)
return -EPERM;

params[2].integer.value = TPM_PPI_FN_GETOPR;
--
1.7.8.6

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