[PATCH 11/34] bcachefs: Don't try to en/decrypt when encryption not available

[Kent Overstreet <kent.overstreet@linux.dev>]

If a btree node says it's encrypted, but the superblock never had an
encryptino key - whoops, that needs to be handled.

Reported-by: syzbot+026f1857b12f5eb3f9e9@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/btree_io.c        | 116 +++++++++++++++++-----------------
 fs/bcachefs/btree_node_scan.c |   3 +
 fs/bcachefs/checksum.c        |  10 ++-
 fs/bcachefs/errcode.h         |   1 +
 fs/bcachefs/io_read.c         |  14 +++-
 5 files changed, 83 insertions(+), 61 deletions(-)

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 2b5da566fbac..5407f1212b4f 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -1045,39 +1045,50 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 
 	while (b->written < (ptr_written ?: btree_sectors(c))) {
 		unsigned sectors;
-		struct nonce nonce;
 		bool first = !b->written;
-		bool csum_bad;
 
-		if (!b->written) {
+		if (first) {
 			i = &b->data->keys;
+		} else {
+			bne = write_block(b);
+			i = &bne->keys;
 
-			btree_err_on(!bch2_checksum_type_valid(c, BSET_CSUM_TYPE(i)),
-				     -BCH_ERR_btree_node_read_err_want_retry,
-				     c, ca, b, i, NULL,
-				     bset_unknown_csum,
-				     "unknown checksum type %llu", BSET_CSUM_TYPE(i));
-
-			nonce = btree_nonce(i, b->written << 9);
+			if (i->seq != b->data->keys.seq)
+				break;
+		}
 
-			struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, b->data);
-			csum_bad = bch2_crc_cmp(b->data->csum, csum);
-			if (csum_bad)
-				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
+		struct nonce nonce = btree_nonce(i, b->written << 9);
+		bool good_csum_type = bch2_checksum_type_valid(c, BSET_CSUM_TYPE(i));
 
-			btree_err_on(csum_bad,
-				     -BCH_ERR_btree_node_read_err_want_retry,
-				     c, ca, b, i, NULL,
-				     bset_bad_csum,
-				     "%s",
-				     (printbuf_reset(&buf),
-				      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), b->data->csum, csum),
-				      buf.buf));
-
-			ret = bset_encrypt(c, i, b->written << 9);
-			if (bch2_fs_fatal_err_on(ret, c,
-					"decrypting btree node: %s", bch2_err_str(ret)))
-				goto fsck_err;
+		btree_err_on(!good_csum_type,
+			     bch2_csum_type_is_encryption(BSET_CSUM_TYPE(i))
+			     ? -BCH_ERR_btree_node_read_err_must_retry
+			     : -BCH_ERR_btree_node_read_err_want_retry,
+			     c, ca, b, i, NULL,
+			     bset_unknown_csum,
+			     "unknown checksum type %llu", BSET_CSUM_TYPE(i));
+
+		if (first) {
+			if (good_csum_type) {
+				struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, b->data);
+				bool csum_bad = bch2_crc_cmp(b->data->csum, csum);
+				if (csum_bad)
+					bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
+
+				btree_err_on(csum_bad,
+					     -BCH_ERR_btree_node_read_err_want_retry,
+					     c, ca, b, i, NULL,
+					     bset_bad_csum,
+					     "%s",
+					     (printbuf_reset(&buf),
+					      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), b->data->csum, csum),
+					      buf.buf));
+
+				ret = bset_encrypt(c, i, b->written << 9);
+				if (bch2_fs_fatal_err_on(ret, c,
+							 "decrypting btree node: %s", bch2_err_str(ret)))
+					goto fsck_err;
+			}
 
 			btree_err_on(btree_node_type_is_extents(btree_node_type(b)) &&
 				     !BTREE_NODE_NEW_EXTENT_OVERWRITE(b->data),
@@ -1088,37 +1099,26 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 
 			sectors = vstruct_sectors(b->data, c->block_bits);
 		} else {
-			bne = write_block(b);
-			i = &bne->keys;
-
-			if (i->seq != b->data->keys.seq)
-				break;
-
-			btree_err_on(!bch2_checksum_type_valid(c, BSET_CSUM_TYPE(i)),
-				     -BCH_ERR_btree_node_read_err_want_retry,
-				     c, ca, b, i, NULL,
-				     bset_unknown_csum,
-				     "unknown checksum type %llu", BSET_CSUM_TYPE(i));
-
-			nonce = btree_nonce(i, b->written << 9);
-			struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, bne);
-			csum_bad = bch2_crc_cmp(bne->csum, csum);
-			if (ca && csum_bad)
-				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
-
-			btree_err_on(csum_bad,
-				     -BCH_ERR_btree_node_read_err_want_retry,
-				     c, ca, b, i, NULL,
-				     bset_bad_csum,
-				     "%s",
-				     (printbuf_reset(&buf),
-				      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), bne->csum, csum),
-				      buf.buf));
-
-			ret = bset_encrypt(c, i, b->written << 9);
-			if (bch2_fs_fatal_err_on(ret, c,
-					"decrypting btree node: %s", bch2_err_str(ret)))
-				goto fsck_err;
+			if (good_csum_type) {
+				struct bch_csum csum = csum_vstruct(c, BSET_CSUM_TYPE(i), nonce, bne);
+				bool csum_bad = bch2_crc_cmp(bne->csum, csum);
+				if (ca && csum_bad)
+					bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
+
+				btree_err_on(csum_bad,
+					     -BCH_ERR_btree_node_read_err_want_retry,
+					     c, ca, b, i, NULL,
+					     bset_bad_csum,
+					     "%s",
+					     (printbuf_reset(&buf),
+					      bch2_csum_err_msg(&buf, BSET_CSUM_TYPE(i), bne->csum, csum),
+					      buf.buf));
+
+				ret = bset_encrypt(c, i, b->written << 9);
+				if (bch2_fs_fatal_err_on(ret, c,
+						"decrypting btree node: %s", bch2_err_str(ret)))
+					goto fsck_err;
+			}
 
 			sectors = vstruct_sectors(bne, c->block_bits);
 		}
diff --git a/fs/bcachefs/btree_node_scan.c b/fs/bcachefs/btree_node_scan.c
index 4b4df31d4b95..327f1a1859b9 100644
--- a/fs/bcachefs/btree_node_scan.c
+++ b/fs/bcachefs/btree_node_scan.c
@@ -159,6 +159,9 @@ static void try_read_btree_node(struct find_btree_nodes *f, struct bch_dev *ca,
 		return;
 
 	if (bch2_csum_type_is_encryption(BSET_CSUM_TYPE(&bn->keys))) {
+		if (!c->chacha20)
+			return;
+
 		struct nonce nonce = btree_nonce(&bn->keys, 0);
 		unsigned bytes = (void *) &bn->keys - (void *) &bn->flags;
 
diff --git a/fs/bcachefs/checksum.c b/fs/bcachefs/checksum.c
index ce8fc677bef9..23a383577d4c 100644
--- a/fs/bcachefs/checksum.c
+++ b/fs/bcachefs/checksum.c
@@ -2,6 +2,7 @@
 #include "bcachefs.h"
 #include "checksum.h"
 #include "errcode.h"
+#include "error.h"
 #include "super.h"
 #include "super-io.h"
 
@@ -252,6 +253,10 @@ int bch2_encrypt(struct bch_fs *c, unsigned type,
 	if (!bch2_csum_type_is_encryption(type))
 		return 0;
 
+	if (bch2_fs_inconsistent_on(!c->chacha20,
+				    c, "attempting to encrypt without encryption key"))
+		return -BCH_ERR_no_encryption_key;
+
 	return do_encrypt(c->chacha20, nonce, data, len);
 }
 
@@ -337,8 +342,9 @@ int __bch2_encrypt_bio(struct bch_fs *c, unsigned type,
 	size_t sgl_len = 0;
 	int ret = 0;
 
-	if (!bch2_csum_type_is_encryption(type))
-		return 0;
+	if (bch2_fs_inconsistent_on(!c->chacha20,
+				    c, "attempting to encrypt without encryption key"))
+		return -BCH_ERR_no_encryption_key;
 
 	darray_init(&sgl);
 
diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
index c989ce4f715f..a12050e9c191 100644
--- a/fs/bcachefs/errcode.h
+++ b/fs/bcachefs/errcode.h
@@ -260,6 +260,7 @@
 	x(EIO,				no_device_to_read_from)			\
 	x(EIO,				missing_indirect_extent)		\
 	x(EIO,				invalidate_stripe_to_dev)		\
+	x(EIO,				no_encryption_key)			\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_fixable)		\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_want_retry)		\
 	x(BCH_ERR_btree_node_read_err,	btree_node_read_err_must_retry)		\
diff --git a/fs/bcachefs/io_read.c b/fs/bcachefs/io_read.c
index eb8d12fd6398..4b6b6d25725b 100644
--- a/fs/bcachefs/io_read.c
+++ b/fs/bcachefs/io_read.c
@@ -830,7 +830,7 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 	if (!pick_ret)
 		goto hole;
 
-	if (pick_ret < 0) {
+	if (unlikely(pick_ret < 0)) {
 		struct printbuf buf = PRINTBUF;
 		bch2_bkey_val_to_text(&buf, c, k);
 
@@ -843,6 +843,18 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 		goto err;
 	}
 
+	if (unlikely(bch2_csum_type_is_encryption(pick.crc.csum_type)) && !c->chacha20) {
+		struct printbuf buf = PRINTBUF;
+		bch2_bkey_val_to_text(&buf, c, k);
+
+		bch_err_inum_offset_ratelimited(c,
+				read_pos.inode, read_pos.offset << 9,
+				"attempting to read encrypted data without encryption key\n  %s",
+				buf.buf);
+		printbuf_exit(&buf);
+		goto err;
+	}
+
 	struct bch_dev *ca = bch2_dev_get_ioref(c, pick.ptr.dev, READ);
 
 	/*
-- 
2.45.2