Merge tag 'pstore-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "Various fixes and tweaks for the pstore subsystem.

  Highlights:

   - use memdup_user() instead of open-coded copies (Geliang Tang)

   - fix record memory leak during initialization (Douglas Anderson)

   - avoid confused compressed record warning (Ankit Kumar)

   - prepopulate record timestamp and remove redundant logic from
     backends"

* tag 'pstore-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  powerpc/nvram: use memdup_user
  pstore: use memdup_user
  pstore: Fix format string to use %u for record id
  pstore: Populate pstore record->time field
  pstore: Create common record initializer
  efi-pstore: Refactor erase routine
  pstore: Avoid potential infinite loop
  pstore: Fix leaked pstore_record in pstore_get_backend_records()
  pstore: Don't warn if data is uncompressed and type is not PSTORE_TYPE_DMESG

drivers/firmware/efi/efi-pstore.c

@@ -4,7 +4,7 @@
 #include <linux/slab.h>
 #include <linux/ucs2_string.h>
 
-#define DUMP_NAME_LEN 52
+#define DUMP_NAME_LEN 66
 
 static bool efivars_pstore_disable =
 	IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
@@ -244,12 +244,12 @@ static int efi_pstore_write(struct pstore_record *record)
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
 	int i, ret = 0;
 
-	record->time.tv_sec = get_seconds();
-	record->time.tv_nsec = 0;
-
 	record->id = generic_id(record->time.tv_sec, record->part,
 				record->count);
 
+	/* Since we copy the entire length of name, make sure it is wiped. */
+	memset(name, 0, sizeof(name));
+
 	snprintf(name, sizeof(name), "dump-type%u-%u-%d-%lu-%c",
 		 record->type, record->part, record->count,
 		 record->time.tv_sec, record->compressed ? 'C' : 'D');
@@ -267,44 +267,20 @@ static int efi_pstore_write(struct pstore_record *record)
 	return ret;
 };
 
-struct pstore_erase_data {
-	struct pstore_record *record;
-	efi_char16_t *name;
-};
-
 /*
  * Clean up an entry with the same name
  */
 static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
 {
-	struct pstore_erase_data *ed = data;
+	efi_char16_t *efi_name = data;
 	efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
-	efi_char16_t efi_name_old[DUMP_NAME_LEN];
-	efi_char16_t *efi_name = ed->name;
-	unsigned long ucs2_len = ucs2_strlen(ed->name);
-	char name_old[DUMP_NAME_LEN];
-	int i;
+	unsigned long ucs2_len = ucs2_strlen(efi_name);
 
 	if (efi_guidcmp(entry->var.VendorGuid, vendor))
 		return 0;
 
-	if (ucs2_strncmp(entry->var.VariableName,
-			  efi_name, (size_t)ucs2_len)) {
-		/*
-		 * Check if an old format, which doesn't support
-		 * holding multiple logs, remains.
-		 */
-		snprintf(name_old, sizeof(name_old), "dump-type%u-%u-%lu",
-			ed->record->type, ed->record->part,
-			ed->record->time.tv_sec);
-
-		for (i = 0; i < DUMP_NAME_LEN; i++)
-			efi_name_old[i] = name_old[i];
-
-		if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
-				  ucs2_strlen(efi_name_old)))
-			return 0;
-	}
+	if (ucs2_strncmp(entry->var.VariableName, efi_name, (size_t)ucs2_len))
+		return 0;
 
 	if (entry->scanning) {
 		/*
@@ -321,35 +297,48 @@ static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
 	return 1;
 }
 
-static int efi_pstore_erase(struct pstore_record *record)
+static int efi_pstore_erase_name(const char *name)
 {
-	struct pstore_erase_data edata;
 	struct efivar_entry *entry = NULL;
-	char name[DUMP_NAME_LEN];
 	efi_char16_t efi_name[DUMP_NAME_LEN];
 	int found, i;
 
+	for (i = 0; i < DUMP_NAME_LEN; i++) {
+		efi_name[i] = name[i];
+		if (name[i] == '\0')
+			break;
+	}
+
+	if (efivar_entry_iter_begin())
+		return -EINTR;
+
+	found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list,
+				    efi_name, &entry);
+	efivar_entry_iter_end();
+
+	if (found && !entry->scanning)
+		efivar_unregister(entry);
+
+	return found ? 0 : -ENOENT;
+}
+
+static int efi_pstore_erase(struct pstore_record *record)
+{
+	char name[DUMP_NAME_LEN];
+	int ret;
+
 	snprintf(name, sizeof(name), "dump-type%u-%u-%d-%lu",
 		 record->type, record->part, record->count,
 		 record->time.tv_sec);
+	ret = efi_pstore_erase_name(name);
+	if (ret != -ENOENT)
+		return ret;
 
-	for (i = 0; i < DUMP_NAME_LEN; i++)
-		efi_name[i] = name[i];
+	snprintf(name, sizeof(name), "dump-type%u-%u-%lu",
+		record->type, record->part, record->time.tv_sec);
+	ret = efi_pstore_erase_name(name);
 
-	edata.record = record;
-	edata.name = efi_name;
-
-	if (efivar_entry_iter_begin())
-		return -EINTR;
-	found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
-
-	if (found && !entry->scanning) {
-		efivar_entry_iter_end();
-		efivar_unregister(entry);
-	} else
-		efivar_entry_iter_end();
-
-	return 0;
+	return ret;
 }
 
 static struct pstore_info efi_pstore_info = {