Re: [PATCH][Trivial] CIFS: Don't free volume_info->UNC until we areentirely done with it.

From: Jeff Layton
Date: Mon Aug 29 2011 - 11:41:30 EST


On Sat, 27 Aug 2011 18:58:34 +0200 (CEST)
Jesper Juhl <jj@xxxxxxxxxxxxx> wrote:

> In cleanup_volume_info_contents() we kfree(volume_info->UNC); and then
> proceed to use that variable on the very next line.
> This causes (at least) Coverity Prevent to complain about use-after-free
> of that variable (and I guess other checkers may do that as well).
> There's not any /real/ problem here since we are just using the value of
> the pointer, not actually dereferencing it, but it's still trivial to
> silence the tool, so why not?
> To me at least it also just seems nicer to defer freeing the variable
> until we are entirely done with it in all respects.
>
> Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
> ---
> fs/cifs/connect.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 633c246..9bb4b10 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2877,9 +2877,9 @@ cleanup_volume_info_contents(struct smb_vol *volume_info)
> {
> kfree(volume_info->username);
> kzfree(volume_info->password);
> - kfree(volume_info->UNC);
> if (volume_info->UNCip != volume_info->UNC + 2)
> kfree(volume_info->UNCip);
> + kfree(volume_info->UNC);
> kfree(volume_info->domainname);
> kfree(volume_info->iocharset);
> kfree(volume_info->prepath);

Seems reasonable for silencing the checker...

Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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