efi-pstore: Read and write to the 'compressed' flag of pstore

In pstore write, Efi will add a character 'C'(compressed) or
D'(decompressed) in its header while writing to persistent store.
In pstore read, read the header and update the 'compressed' flag
accordingly.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 9a5425f3f885..5002d50e3781 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -35,6 +35,7 @@ struct pstore_read_data {
         enum pstore_type_id *type;
         int *count;
         struct timespec *timespec;
+        bool *compressed;
         char **buf;
 };
 
@@ -42,7 +43,7 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
 {
         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
         struct pstore_read_data *cb_data = data;
-        char name[DUMP_NAME_LEN];
+        char name[DUMP_NAME_LEN], data_type;
         int i;
         int cnt;
         unsigned int part;
@@ -54,12 +55,23 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
         for (i = 0; i < DUMP_NAME_LEN; i++)
                 name[i] = entry->var.VariableName[i];
 
-        if (sscanf(name, "dump-type%u-%u-%d-%lu",
+        if (sscanf(name, "dump-type%u-%u-%d-%lu-%c",
+                   cb_data->type, &part, &cnt, &time, &data_type) == 5) {
+                *cb_data->id = part;
+                *cb_data->count = cnt;
+                cb_data->timespec->tv_sec = time;
+                cb_data->timespec->tv_nsec = 0;
+                if (data_type == 'C')
+                        *cb_data->compressed = true;
+                else
+                        *cb_data->compressed = false;
+        } else if (sscanf(name, "dump-type%u-%u-%d-%lu",
                    cb_data->type, &part, &cnt, &time) == 4) {
                 *cb_data->id = part;
                 *cb_data->count = cnt;
                 cb_data->timespec->tv_sec = time;
                 cb_data->timespec->tv_nsec = 0;
+                *cb_data->compressed = false;
         } else if (sscanf(name, "dump-type%u-%u-%lu",
                           cb_data->type, &part, &time) == 3) {
                 /*
@@ -71,6 +83,7 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
                 *cb_data->count = 0;
                 cb_data->timespec->tv_sec = time;
                 cb_data->timespec->tv_nsec = 0;
+                *cb_data->compressed = false;
         } else
                 return 0;
 
@@ -96,6 +109,7 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
         data.type = type;
         data.count = count;
         data.timespec = timespec;
+        data.compressed = compressed;
         data.buf = buf;
 
         return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
@@ -112,8 +126,8 @@ static int efi_pstore_write(enum pstore_type_id type,
         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
         int i, ret = 0;
 
-        sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
-                get_seconds());
+        sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count,
+                get_seconds(), compressed ? 'C' : 'D');
 
         for (i = 0; i < DUMP_NAME_LEN; i++)
                 efi_name[i] = name[i];