crypto: 842 - Add CRC and validation support
This patch adds CRC generation and validation support for nx-842.
Add CRC flag so that nx842 coprocessor includes CRC during compression
and validates during decompression.
Also changes in 842 SW compression to append CRC value at the end
of template and checks during decompression.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/lib/842/842_decompress.c b/lib/842/842_decompress.c
index 5446ff0..8881dad 100644
--- a/lib/842/842_decompress.c
+++ b/lib/842/842_decompress.c
@@ -285,6 +285,7 @@
struct sw842_param p;
int ret;
u64 op, rep, tmp, bytes, total;
+ u64 crc;
p.in = (u8 *)in;
p.bit = 0;
@@ -375,6 +376,22 @@
}
} while (op != OP_END);
+ /*
+ * crc(0:31) is saved in compressed data starting with the
+ * next bit after End of stream template.
+ */
+ ret = next_bits(&p, &crc, CRC_BITS);
+ if (ret)
+ return ret;
+
+ /*
+ * Validate CRC saved in compressed data.
+ */
+ if (crc != (u64)crc32_be(0, out, total - p.olen)) {
+ pr_debug("CRC mismatch for decompression\n");
+ return -EINVAL;
+ }
+
if (unlikely((total - p.olen) > UINT_MAX))
return -ENOSPC;