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From: Oliver Neukum <>
To: Johan Hovold <>,
	Greg Kroah-Hartman <>
Subject: Re: [PATCH v2 2/3] USB: cdc-acm: fix unprivileged TIOCCSERIAL
Date: Thu, 08 Apr 2021 15:32:26 +0200
Message-ID: <> (raw)
In-Reply-To: <>

Am Donnerstag, den 08.04.2021, 15:16 +0200 schrieb Johan Hovold:
> TIOCSSERIAL is a horrid, underspecified, legacy interface which for most
> serial devices is only useful for setting the close_delay and
> closing_wait parameters.
> A non-privileged user has only ever been able to set the since long
> deprecated ASYNC_SPD flags and trying to change any other *supported*
> feature should result in -EPERM being returned. Setting the current
> values for any supported features should return success.
> Fix the cdc-acm implementation which instead indicated that the
> TIOCSSERIAL ioctl was not even implemented when a non-privileged user
> set the current values.
> Fixes: ba2d8ce9db0a ("cdc-acm: implement TIOCSSERIAL to avoid blocking close(2)")
> Signed-off-by: Johan Hovold <>
Acked-by: Oliver Neukum <>

  reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08 13:15 [PATCH v2 0/3] TIOCSSERIAL fixes Johan Hovold
2021-04-08 13:16 ` [PATCH v2 1/3] Revert "USB: cdc-acm: fix rounding error in TIOCSSERIAL" Johan Hovold
2021-04-08 13:31   ` Oliver Neukum
2021-04-08 13:16 ` [PATCH v2 2/3] USB: cdc-acm: fix unprivileged TIOCCSERIAL Johan Hovold
2021-04-08 13:32   ` Oliver Neukum [this message]
2021-04-08 13:16 ` [PATCH v2 3/3] USB: cdc-acm: fix TIOCGSERIAL implementation Johan Hovold
2021-04-08 13:33   ` Oliver Neukum

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