[PATCH v4 46/46] btrfs: load the inode context before sending writes

Josef Bacik
2023-12-01T22:12:54Z

For send we will read the pages and copy them into our buffer. Use the
fscrypt_inode_open helper to make sure the key is loaded properly before
trying to read from the inode so the contents are properly decrypted.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/send.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index de77321777f4..3475b4cea09d 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -5392,6 +5392,37 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
return ret;
}

+static int load_fscrypt_context(struct send_ctx *sctx)
+{
+ struct btrfs_root *root = sctx->send_root;
+ struct name_cache_entry *nce;
+ struct inode *dir;
+ int ret;
+
+ if (!IS_ENCRYPTED(sctx->cur_inode))
+ return 0;
+
+ /*
+ * We're encrypted, we need to load the parent inode in order to make
+ * sure the encryption context is loaded, we use this after calling
+ * get_cur_path() so our nce for the current inode should be here. If
+ * not handle it, but ASSERT() for developers.
+ */
+ nce = name_cache_search(sctx, sctx->cur_ino, sctx->cur_inode_gen);
+ if (!nce) {
+ ASSERT(nce);
+ return -EINVAL;
+ }
+
+ dir = btrfs_iget(root->fs_info->sb, nce->parent_ino, root);
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ ret = fscrypt_inode_open(dir, sctx->cur_inode);
+ iput(dir);
+ return ret;
+}
+
/*
* Read some bytes from the current inode/file and send a write command to
* user space.
@@ -5415,7 +5446,9 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto out;
-
+ ret = load_fscrypt_context(sctx);
+ if (ret < 0)
+ goto out;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
ret = put_file_data(sctx, offset, len);
--
2.41.0