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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hyunchul Lee <hyc.lee@gmail.com>,
        Namjae Jeon <linkinjeon@kernel.org>,
        Steve French <stfrench@microsoft.com>
Subject: [PATCH 6.0 113/862] ksmbd: fix incorrect handling of iterate_dir
Date:   Wed, 19 Oct 2022 10:23:20 +0200
Message-Id: <20221019083254.912900126@linuxfoundation.org>
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From: Namjae Jeon <linkinjeon@kernel.org>

commit 88541cb414b7a2450c45fc9c131b37b5753b7679 upstream.

if iterate_dir() returns non-negative value, caller has to treat it
as normal and check there is any error while populating dentry
information. ksmbd doesn't have to do anything because ksmbd already
checks too small OutputBufferLength to store one file information.

And because ctx->pos is set to file->f_pos when iterative_dir is called,
remove restart_ctx(). And if iterate_dir() return -EIO, which mean
directory entry is corrupted, return STATUS_FILE_CORRUPT_ERROR error
response.

This patch fixes some failure of SMB2_QUERY_DIRECTORY, which happens when
ntfs3 is local filesystem.

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Cc: stable@vger.kernel.org
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/ksmbd/smb2pdu.c |   14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -3808,11 +3808,6 @@ static int __query_dir(struct dir_contex
 	return 0;
 }
 
-static void restart_ctx(struct dir_context *ctx)
-{
-	ctx->pos = 0;
-}
-
 static int verify_info_level(int info_level)
 {
 	switch (info_level) {
@@ -3921,7 +3916,6 @@ int smb2_query_dir(struct ksmbd_work *wo
 	if (srch_flag & SMB2_REOPEN || srch_flag & SMB2_RESTART_SCANS) {
 		ksmbd_debug(SMB, "Restart directory scan\n");
 		generic_file_llseek(dir_fp->filp, 0, SEEK_SET);
-		restart_ctx(&dir_fp->readdir_data.ctx);
 	}
 
 	memset(&d_info, 0, sizeof(struct ksmbd_dir_info));
@@ -3968,11 +3962,9 @@ int smb2_query_dir(struct ksmbd_work *wo
 	 */
 	if (!d_info.out_buf_len && !d_info.num_entry)
 		goto no_buf_len;
-	if (rc == 0)
-		restart_ctx(&dir_fp->readdir_data.ctx);
-	if (rc == -ENOSPC)
+	if (rc > 0 || rc == -ENOSPC)
 		rc = 0;
-	if (rc)
+	else if (rc)
 		goto err_out;
 
 	d_info.wptr = d_info.rptr;
@@ -4029,6 +4021,8 @@ err_out2:
 		rsp->hdr.Status = STATUS_NO_MEMORY;
 	else if (rc == -EFAULT)
 		rsp->hdr.Status = STATUS_INVALID_INFO_CLASS;
+	else if (rc == -EIO)
+		rsp->hdr.Status = STATUS_FILE_CORRUPT_ERROR;
 	if (!rsp->hdr.Status)
 		rsp->hdr.Status = STATUS_UNEXPECTED_IO_ERROR;