pstore: Allocate records on heap instead of stack

In preparation for handling records off to pstore_mkfile(), allocate the
record instead of reusing stack. This still always frees the record,
though, since pstore_mkfile() isn't yet keeping it.

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

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index d897e2f..0723266 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -818,8 +818,7 @@ static void decompress_record(struct pstore_record *record)
 void pstore_get_records(int quiet)
 {
        struct pstore_info *psi = psinfo;
-       struct pstore_record    record = { .psi = psi, };
-       int                     failed = 0, rc;
+       int failed = 0;
 
        if (!psi)
                return;
@@ -833,19 +832,34 @@ void pstore_get_records(int quiet)
         * may reallocate record.buf. On success, pstore_mkfile() will keep
         * the record.buf, so free it only on failure.
         */
-       while ((record.size = psi->read(&record)) > 0) {
-               decompress_record(&record);
-               rc = pstore_mkfile(&record);
+       for (;;) {
+               struct pstore_record *record;
+               int rc;
+
+               record = kzalloc(sizeof(*record), GFP_KERNEL);
+               if (!record) {
+                       pr_err("out of memory creating record\n");
+                       break;
+               }
+               record->psi = psi;
+
+               record->size = psi->read(record);
+
+               /* No more records left in backend? */
+               if (record->size <= 0)
+                       break;
+
+               decompress_record(record);
+               rc = pstore_mkfile(record);
                if (rc) {
                        /* pstore_mkfile() did not take buf, so free it. */
-                       kfree(record.buf);
+                       kfree(record->buf);
                        if (rc != -EEXIST || !quiet)
                                failed++;
                }
 
                /* Reset for next record. */
-               memset(&record, 0, sizeof(record));
-               record.psi = psi;
+               kfree(record);
        }
        if (psi->close)
                psi->close(psi);