Disallow slashes in filename in downloads.download()

Disallow slashes in filename in downloads.download()

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=134588

[Randy Smith (Not in Mondays), 2012-04-27 19:40:05]

LGTM, but I'd like Asanka's eyes to pass over it, as he's seen code like this in
the past and it's worth while making extra-sure there's no way around it.  If we
are disallowing a superset of the ideal set of excluded filenames, that's ok. 
But we really need to make sure we're not disallowing a subset, as that's a
security hole.

[asanka, 2012-04-27 20:32:47]

LGTM.

I imagine the purpose of ValidateFilename() is to inform the caller that the
filename is invalid rather than protect against malicious extensions, correct?

Even without this check, the slashes should just be getting overwritten by
harmless underscores at filename determination time.

[benjhayden, 2012-04-28 18:37:19]

On 2012/04/27 20:32:47, asanka wrote:
> LGTM.
> 
> I imagine the purpose of ValidateFilename() is to inform the caller that the
> filename is invalid rather than protect against malicious extensions, correct?
> 
> Even without this check, the slashes should just be getting overwritten by
> harmless underscores at filename determination time.

Yes, the purpose of this change is simply to notify the user that slashes do not
do what they would expect, and to discourage using them until we can correctly
implement the expected functionality.

[commit-bot: I haz the power, 2012-04-28 18:37:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/benjhayden@chromium.org/10103004/18001

[commit-bot: I haz the power, 2012-04-30 17:38:58]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/benjhayden@chromium.org/10103004/30002

[commit-bot: I haz the power, 2012-04-30 20:40:05]

Change committed as 134588