1 files changed, 49 insertions, 0 deletions

diff --git a/lib/zlib_inflate/infutil.c b/lib/zlib_inflate/infutil.c
new file mode 100644
index 000000000000..4824c2cc7a09
--- /dev/null
+++ b/lib/zlib_inflate/infutil.c
@@ -0,0 +1,49 @@
+#include <linux/zutil.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+/* Utility function: initialize zlib, unpack binary blob, clean up zlib,
+ * return len or negative error code.
+ */
+int zlib_inflate_blob(void *gunzip_buf, unsigned int sz,
+                      const void *buf, unsigned int len)
+{
+        const u8 *zbuf = buf;
+        struct z_stream_s *strm;
+        int rc;
+
+        rc = -ENOMEM;
+        strm = kmalloc(sizeof(*strm), GFP_KERNEL);
+        if (strm == NULL)
+                goto gunzip_nomem1;
+        strm->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
+        if (strm->workspace == NULL)
+                goto gunzip_nomem2;
+
+        /* gzip header (1f,8b,08... 10 bytes total + possible asciz filename)
+         * expected to be stripped from input
+         */
+        strm->next_in = zbuf;
+        strm->avail_in = len;
+        strm->next_out = gunzip_buf;
+        strm->avail_out = sz;
+
+        rc = zlib_inflateInit2(strm, -MAX_WBITS);
+        if (rc == Z_OK) {
+                rc = zlib_inflate(strm, Z_FINISH);
+                /* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
+                if (rc == Z_STREAM_END)
+                        rc = sz - strm->avail_out;
+                else
+                        rc = -EINVAL;
+                zlib_inflateEnd(strm);
+        } else
+                rc = -EINVAL;
+
+        kfree(strm->workspace);
+gunzip_nomem2:
+        kfree(strm);
+gunzip_nomem1:
+        return rc; /* returns Z_OK (0) if successful */
+}