TPM: fix transmit_cmd error logic

It's incorrect to assume that buffers returned by the TPM 10 bytes long are always error reports. This patches parses the error field in its header instead. The error report is now being printed using dev_err() instead of dev_dbg(), making it easier for users to provide more detailed bug reports. Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
git-mirror · Nov 16, 2011 · b9e3238 · b9e3238
1 parent 2f592f2
commit b9e3238
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Showing 3 changed files with 9 additions and 10 deletions.
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
@@ -438,7 +438,6 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 }
 
 #define TPM_DIGEST_SIZE 20
-#define TPM_ERROR_SIZE 10
 #define TPM_RET_CODE_IDX 6
 
 enum tpm_capabilities {
@@ -467,12 +466,14 @@ static ssize_t transmit_cmd(struct tpm_chip *chip, struct tpm_cmd_t *cmd,
 	len = tpm_transmit(chip,(u8 *) cmd, len);
 	if (len <  0)
 		return len;
-	if (len == TPM_ERROR_SIZE) {
-		err = be32_to_cpu(cmd->header.out.return_code);
-		dev_dbg(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
-		return err;
-	}
-	return 0;
+	else if (len < TPM_HEADER_SIZE)
+		return -EFAULT;
+
+	err = be32_to_cpu(cmd->header.out.return_code);
+	if (err != 0)
+		dev_err(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
+
+	return err;
 }
 
 #define TPM_INTERNAL_RESULT_SIZE 200

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
@@ -39,7 +39,7 @@ enum tpm_addr {
 };
 
 #define TPM_WARN_DOING_SELFTEST 0x802
-
+#define TPM_HEADER_SIZE		10
 extern ssize_t tpm_show_pubek(struct device *, struct device_attribute *attr,
 				char *);
 extern ssize_t tpm_show_pcrs(struct device *, struct device_attribute *attr,

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
@@ -29,8 +29,6 @@
 #include <linux/freezer.h>
 #include "tpm.h"
 
-#define TPM_HEADER_SIZE 10
-
 enum tis_access {
 	TPM_ACCESS_VALID = 0x80,
 	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,