Re: [PATCH] cifs: smb2ops: Fix NULL check in smb2_query_symlink
From: Pavel Shilovsky
Date: Fri Apr 13 2018 - 19:55:10 EST
2018-04-13 8:13 GMT-07:00 Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>:
> The current code null checks variable err_buf, which is always null
> when it is checked, hence utf16_path is free'd and the function
> returns -ENOENT everytime it is called, making it impossible for the
> execution path to reach the following code:
>
> err_buf = err_iov.iov_base;
>
> Fix this by null checking err_iov.iov_base instead of err_buf. Also,
> notice that err_buf no longer needs to be initialized to NULL.
>
> Addresses-Coverity-ID: 1467876 ("Logically dead code")
> Fixes: 2d636199e400 ("cifs: Change SMB2_open to return an iov for the error parameter")
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
> fs/cifs/smb2ops.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index b4ae932..38ebf3f 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -1452,7 +1452,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
> struct cifs_open_parms oparms;
> struct cifs_fid fid;
> struct kvec err_iov = {NULL, 0};
> - struct smb2_err_rsp *err_buf = NULL;
> + struct smb2_err_rsp *err_buf;
> struct smb2_symlink_err_rsp *symlink;
> unsigned int sub_len;
> unsigned int sub_offset;
> @@ -1476,7 +1476,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
>
> rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_iov);
>
> - if (!rc || !err_buf) {
> + if (!rc || !err_iov.iov_base) {
> kfree(utf16_path);
> return -ENOENT;
> }
> --
> 2.7.4
>
> --
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Thanks!
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
--
Best regards,
Pavel Shilovsky