1 files changed, 32 insertions, 13 deletions

diff --git a/drivers/char/tpm/eventlog/efi.c b/drivers/char/tpm/eventlog/efi.c
index 6bb023de17f1..4e9d7c2bf32e 100644
--- a/drivers/char/tpm/eventlog/efi.c
+++ b/drivers/char/tpm/eventlog/efi.c
@@ -6,6 +6,7 @@
  *      Thiebaud Weksteen <tweek@google.com>
  */
 
+#include <linux/device.h>
 #include <linux/efi.h>
 #include <linux/tpm_eventlog.h>
 
@@ -17,6 +18,7 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 {
 
 	struct efi_tcg2_final_events_table *final_tbl = NULL;
+	int final_events_log_size = efi_tpm_final_log_size;
 	struct linux_efi_tpm_eventlog *log_tbl;
 	struct tpm_bios_log *log;
 	u32 log_size;
@@ -41,6 +43,11 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 	log_size = log_tbl->size;
 	memunmap(log_tbl);
 
+	if (!log_size) {
+		pr_warn("UEFI TPM log area empty\n");
+		return -EIO;
+	}
+
 	log_tbl = memremap(efi.tpm_log, sizeof(*log_tbl) + log_size,
 			   MEMREMAP_WB);
 	if (!log_tbl) {
@@ -49,7 +56,7 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 	}
 
 	/* malloc EventLog space */
-	log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
+	log->bios_event_log = devm_kmemdup(&chip->dev, log_tbl->log, log_size, GFP_KERNEL);
 	if (!log->bios_event_log) {
 		ret = -ENOMEM;
 		goto out;
@@ -61,27 +68,35 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 	ret = tpm_log_version;
 
 	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
-	    efi_tpm_final_log_size == 0 ||
+	    final_events_log_size == 0 ||
 	    tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
 		goto out;
 
 	final_tbl = memremap(efi.tpm_final_log,
-			     sizeof(*final_tbl) + efi_tpm_final_log_size,
+			     sizeof(*final_tbl) + final_events_log_size,
 			     MEMREMAP_WB);
 	if (!final_tbl) {
 		pr_err("Could not map UEFI TPM final log\n");
-		kfree(log->bios_event_log);
+		devm_kfree(&chip->dev, log->bios_event_log);
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	efi_tpm_final_log_size -= log_tbl->final_events_preboot_size;
+	/*
+	 * The 'final events log' size excludes the 'final events preboot log'
+	 * at its beginning.
+	 */
+	final_events_log_size -= log_tbl->final_events_preboot_size;
 
-	tmp = krealloc(log->bios_event_log,
-		       log_size + efi_tpm_final_log_size,
-		       GFP_KERNEL);
+	/*
+	 * Allocate memory for the 'combined log' where we will append the
+	 * 'final events log' to.
+	 */
+	tmp = devm_krealloc(&chip->dev, log->bios_event_log,
+			    log_size + final_events_log_size,
+			    GFP_KERNEL);
 	if (!tmp) {
-		kfree(log->bios_event_log);
+		devm_kfree(&chip->dev, log->bios_event_log);
 		ret = -ENOMEM;
 		goto out;
 	}
@@ -89,15 +104,19 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 	log->bios_event_log = tmp;
 
 	/*
-	 * Copy any of the final events log that didn't also end up in the
-	 * main log. Events can be logged in both if events are generated
+	 * Append any of the 'final events log' that didn't also end up in the
+	 * 'main log'. Events can be logged in both if events are generated
 	 * between GetEventLog() and ExitBootServices().
 	 */
 	memcpy((void *)log->bios_event_log + log_size,
 	       final_tbl->events + log_tbl->final_events_preboot_size,
-	       efi_tpm_final_log_size);
+	       final_events_log_size);
+	/*
+	 * The size of the 'combined log' is the size of the 'main log' plus
+	 * the size of the 'final events log'.
+	 */
 	log->bios_event_log_end = log->bios_event_log +
-		log_size + efi_tpm_final_log_size;
+		log_size + final_events_log_size;
 
 out:
 	memunmap(final_tbl);