Commit 088aaf17 authored Apr 06, 2019 by ZhangXiaoxu Committed by Steve French Apr 16, 2019

cifs: Fix use-after-free in SMB2_read



There is a KASAN use-after-free:
BUG: KASAN: use-after-free in SMB2_read+0x1136/0x1190
Read of size 8 at addr ffff8880b4e45e50 by task ln/1009

Should not release the 'req' because it will use in the trace.

Fixes: eccb4422 ("smb3: Add ftrace tracepoints for improved SMB3 debugging")

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> 4.18+
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

parent 6a3eb336

fs/cifs/smb2pdu.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3448,8 +3448,6 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
		rqst.rq_nvec = 1;

		rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
		cifs_small_buf_release(req);

		rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;

		if (rc) {
		@@ -3471,6 +3469,8 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
		io_parms->tcon->tid, ses->Suid,
		io_parms->offset, io_parms->length);

		cifs_small_buf_release(req);

		*nbytes = le32_to_cpu(rsp->DataLength);
		if ((*nbytes > CIFS_MAX_MSGSIZE) \|\|
		(*nbytes > io_parms->length)) {

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