pstore: Extract common arguments into structure

The read/mkfile pair pass the same arguments and should be cleared
between calls. Move to a structure and wipe it after every loop.

Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 320a673..f45228e 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -766,16 +766,9 @@ EXPORT_SYMBOL_GPL(pstore_unregister);
 void pstore_get_records(int quiet)
 {
        struct pstore_info *psi = psinfo;
-       char                    *buf = NULL;
-       ssize_t                 size;
-       u64                     id;
-       int                     count;
-       enum pstore_type_id     type;
-       struct timespec         time;
+       struct pstore_record    record = { .psi = psi, };
        int                     failed = 0, rc;
-       bool                    compressed;
        int                     unzipped_len = -1;
-       ssize_t                 ecc_notice_size = 0;
 
        if (!psi)
                return;
@@ -784,39 +777,51 @@ void pstore_get_records(int quiet)
        if (psi->open && psi->open(psi))
                goto out;
 
-       while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
-                                &ecc_notice_size, psi)) > 0) {
-               if (compressed && (type == PSTORE_TYPE_DMESG)) {
+       while ((record.size = psi->read(&record.id, &record.type,
+                                &record.count, &record.time,
+                                &record.buf, &record.compressed,
+                                &record.ecc_notice_size,
+                                record.psi)) > 0) {
+               if (record.compressed &&
+                   record.type == PSTORE_TYPE_DMESG) {
                        if (big_oops_buf)
-                               unzipped_len = pstore_decompress(buf,
-                                                       big_oops_buf, size,
+                               unzipped_len = pstore_decompress(
+                                                       record.buf,
+                                                       big_oops_buf,
+                                                       record.size,
                                                        big_oops_buf_sz);
 
                        if (unzipped_len > 0) {
-                               if (ecc_notice_size)
+                               if (record.ecc_notice_size)
                                        memcpy(big_oops_buf + unzipped_len,
-                                              buf + size, ecc_notice_size);
-                               kfree(buf);
-                               buf = big_oops_buf;
-                               size = unzipped_len;
-                               compressed = false;
+                                              record.buf + record.size,
+                                              record.ecc_notice_size);
+                               kfree(record.buf);
+                               record.buf = big_oops_buf;
+                               record.size = unzipped_len;
+                               record.compressed = false;
                        } else {
                                pr_err("decompression failed;returned %d\n",
                                       unzipped_len);
-                               compressed = true;
+                               record.compressed = true;
                        }
                }
-               rc = pstore_mkfile(type, psi->name, id, count, buf,
-                                  compressed, size + ecc_notice_size,
-                                  time, psi);
+               rc = pstore_mkfile(record.type, psi->name, record.id,
+                                  record.count, record.buf,
+                                  record.compressed,
+                                  record.size + record.ecc_notice_size,
+                                  record.time, record.psi);
                if (unzipped_len < 0) {
                        /* Free buffer other than big oops */
-                       kfree(buf);
-                       buf = NULL;
+                       kfree(record.buf);
+                       record.buf = NULL;
                } else
                        unzipped_len = -1;
                if (rc && (rc != -EEXIST || !quiet))
                        failed++;
+
+               memset(&record, 0, sizeof(record));
+               record.psi = psi;
        }
        if (psi->close)
                psi->close(psi);

diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 56477ce..7454680 100644 (file)
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -30,6 +30,8 @@
 #include <linux/time.h>
 #include <linux/types.h>
 
+struct module;
+
 /* pstore record types (see fs/pstore/inode.c for filename templates) */
 enum pstore_type_id {
        PSTORE_TYPE_DMESG       = 0,
@@ -45,7 +47,31 @@ enum pstore_type_id {
        PSTORE_TYPE_UNKNOWN     = 255
 };
 
-struct module;
+struct pstore_info;
+/**
+ * struct pstore_record - details of a pstore record entry
+ * @psi:       pstore backend driver information
+ * @type:      pstore record type
+ * @id:                per-type unique identifier for record
+ * @time:      timestamp of the record
+ * @count:     for PSTORE_TYPE_DMESG, the Oops count.
+ * @compressed:        for PSTORE_TYPE_DMESG, whether the buffer is compressed
+ * @buf:       pointer to record contents
+ * @size:      size of @buf
+ * @ecc_notice_size:
+ *             ECC information for @buf
+ */
+struct pstore_record {
+       struct pstore_info      *psi;
+       enum pstore_type_id     type;
+       u64                     id;
+       struct timespec         time;
+       int                     count;
+       bool                    compressed;
+       char                    *buf;
+       ssize_t                 size;
+       ssize_t                 ecc_notice_size;
+};
 
 /**
  * struct pstore_info - backend pstore driver structure