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SubjectRe: [PATCH 2/2] cifs: Allocate memory for all iovs in smb2_ioctl
ср, 15 мая 2019 г. в 14:10, <longli@linuxonhyperv.com>:
>
> From: Long Li <longli@microsoft.com>
>
> An IOCTL uses up to 2 iovs. The 1st iov is the command itself, the 2nd iov is
> optional data for that command. The 1st iov is always allocated on the heap
> but the 2nd iov may point to a variable on the stack. This will trigger an
> error when passing the 2nd iov for RDMA I/O.
>
> Fix this by allocating a buffer for the 2nd iov.
>
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
> fs/cifs/smb2pdu.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 29f011d8d8e2..710ceb875161 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -2538,11 +2538,25 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
> struct kvec *iov = rqst->rq_iov;
> unsigned int total_len;
> int rc;
> + char *in_data_buf;
>
> rc = smb2_plain_req_init(SMB2_IOCTL, tcon, (void **) &req, &total_len);
> if (rc)
> return rc;
>
> + if (indatalen) {
> + /*
> + * indatalen is usually small at a couple of bytes max, so
> + * just allocate through generic pool
> + */
> + in_data_buf = kmalloc(indatalen, GFP_NOFS);
> + if (!in_data_buf) {
> + cifs_small_buf_release(req);
> + return -ENOMEM;
> + }
> + memcpy(in_data_buf, in_data, indatalen);
> + }
> +
> req->CtlCode = cpu_to_le32(opcode);
> req->PersistentFileId = persistent_fid;
> req->VolatileFileId = volatile_fid;
> @@ -2563,7 +2577,7 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
> cpu_to_le32(offsetof(struct smb2_ioctl_req, Buffer));
> rqst->rq_nvec = 2;
> iov[0].iov_len = total_len - 1;
> - iov[1].iov_base = in_data;
> + iov[1].iov_base = in_data_buf;
> iov[1].iov_len = indatalen;
> } else {
> rqst->rq_nvec = 1;
> @@ -2605,8 +2619,11 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
> void
> SMB2_ioctl_free(struct smb_rqst *rqst)
> {
> - if (rqst && rqst->rq_iov)
> + if (rqst && rqst->rq_iov) {
> cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
> + if (rqst->rq_iov[1].iov_len)
> + kfree(rqst->rq_iov[1].iov_base);
> + }
> }
>
>
> --
> 2.17.1
>

Looks correct.

Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

--
Best regards,
Pavel Shilovsky

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