Function arc_hdr_decrypt

freebsd/contrib/openzfs/module/zfs/arc.c:1866–1930

* This function will take a header that only has raw encrypted data in * b_crypt_hdr.b_rabd and decrypt it into a new buffer which is stored in * b_l1hdr.b_pabd. If designated in the header flags, this function will * also decompress the data. */

 * also decompress the data.
 */
static int
arc_hdr_decrypt(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb)
{
	int ret;
	abd_t *cabd = NULL;
	void *tmp = NULL;
	boolean_t no_crypt = B_FALSE;
	boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS);

	ASSERT(HDR_EMPTY_OR_LOCKED(hdr));
	ASSERT(HDR_ENCRYPTED(hdr));

	arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT);

	ret = spa_do_crypt_abd(B_FALSE, spa, zb, hdr->b_crypt_hdr.b_ot,
	    B_FALSE, bswap, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv,
	    hdr->b_crypt_hdr.b_mac, HDR_GET_PSIZE(hdr), hdr->b_l1hdr.b_pabd,
	    hdr->b_crypt_hdr.b_rabd, &no_crypt);
	if (ret != 0)
		goto error;

	if (no_crypt) {
		abd_copy(hdr->b_l1hdr.b_pabd, hdr->b_crypt_hdr.b_rabd,
		    HDR_GET_PSIZE(hdr));
	}

	/*
	 * If this header has disabled arc compression but the b_pabd is
	 * compressed after decrypting it, we need to decompress the newly
	 * decrypted data.
	 */
	if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF &&
	    !HDR_COMPRESSION_ENABLED(hdr)) {
		/*
		 * We want to make sure that we are correctly honoring the
		 * zfs_abd_scatter_enabled setting, so we allocate an abd here
		 * and then loan a buffer from it, rather than allocating a
		 * linear buffer and wrapping it in an abd later.
		 */
		cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, B_TRUE);
		tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr));

		ret = zio_decompress_data(HDR_GET_COMPRESS(hdr),
		    hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr),
		    HDR_GET_LSIZE(hdr), &hdr->b_complevel);
		if (ret != 0) {
			abd_return_buf(cabd, tmp, arc_hdr_size(hdr));
			goto error;
		}

		abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr));
		arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd,
		    arc_hdr_size(hdr), hdr);
		hdr->b_l1hdr.b_pabd = cabd;
	}

	return (0);