From patchwork Fri Oct 20 01:18:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Kicinski X-Patchwork-Id: 13429954 X-Patchwork-Delegate: kuba@kernel.org Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 404C939E for ; Fri, 20 Oct 2023 01:18:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PqAhyEQD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63BA9C433C9; Fri, 20 Oct 2023 01:18:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697764738; bh=jwf0kIkzjClGiJzzxrsDWzhWMg0TOqyIQL/vjbwvzwk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PqAhyEQDGWBvS0/bASrp1K2q1oVryM2UDQ5tP1ZmDz7Xe1y0n6ns75ch+WJj1M86j +svbHUxQerWLDr/6dOsL4/9N9HnGGQFx0H6cDi9OUSE11ynL869pNCJKJLWcycKyLr IPweU8k5LODuEZIptOciyMx/DRZnrMHBaUpHmC1AlQCJP1xz6bxNaPrCmEp4MyCopd 3uiSVPulmzhfZRlsEMqlDXzov8GU+9Jk0EfuS44c3TunQlQmwiDfqx4fZPLEquBwak eAqa7XtmcIkSCDbCXgVFpq3FFLCJZOQ8ACRkH+v5FOkvC3h1Ao4FEzwq5Blp+yirQt BhDoAhZ7SXKrw== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, johannes.berg@intel.com, mpe@ellerman.id.au, j@w1.fi, jiri@resnulli.us Subject: [PATCH net-next 1/6] net: don't use input buffer of __dev_alloc_name() as a scratch space Date: Thu, 19 Oct 2023 18:18:51 -0700 Message-ID: <20231020011856.3244410-2-kuba@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231020011856.3244410-1-kuba@kernel.org> References: <20231020011856.3244410-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Callers of __dev_alloc_name() want to pass dev->name as the output buffer. Make __dev_alloc_name() not clobber that buffer on failure, and remove the workarounds in callers. dev_alloc_name_ns() is now completely unnecessary. The extra strscpy() added here will be gone by the end of the patch series. Signed-off-by: Jakub Kicinski Reviewed-by: Jiri Pirko --- net/core/dev.c | 33 ++++++++------------------------- 1 file changed, 8 insertions(+), 25 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 1025dc79bc49..874c7daa81f5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1057,7 +1057,7 @@ EXPORT_SYMBOL(dev_valid_name); * __dev_alloc_name - allocate a name for a device * @net: network namespace to allocate the device name in * @name: name format string - * @buf: scratch buffer and result name string + * @res: result name string * * Passed a format string - eg "lt%d" it will try and find a suitable * id. It scans list of devices to build up a free map, then chooses @@ -1068,13 +1068,14 @@ EXPORT_SYMBOL(dev_valid_name); * Returns the number of the unit assigned or a negative errno code. */ -static int __dev_alloc_name(struct net *net, const char *name, char *buf) +static int __dev_alloc_name(struct net *net, const char *name, char *res) { int i = 0; const char *p; const int max_netdevices = 8*PAGE_SIZE; unsigned long *inuse; struct net_device *d; + char buf[IFNAMSIZ]; if (!dev_valid_name(name)) return -EINVAL; @@ -1124,8 +1125,10 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) } snprintf(buf, IFNAMSIZ, name, i); - if (!netdev_name_in_use(net, buf)) + if (!netdev_name_in_use(net, buf)) { + strscpy(res, buf, IFNAMSIZ); return i; + } /* It is possible to run out of possible slots * when the name is long and there isn't enough space left @@ -1154,20 +1157,6 @@ static int dev_prep_valid_name(struct net *net, struct net_device *dev, return 0; } -static int dev_alloc_name_ns(struct net *net, - struct net_device *dev, - const char *name) -{ - char buf[IFNAMSIZ]; - int ret; - - BUG_ON(!net); - ret = __dev_alloc_name(net, name, buf); - if (ret >= 0) - strscpy(dev->name, buf, IFNAMSIZ); - return ret; -} - /** * dev_alloc_name - allocate a name for a device * @dev: device @@ -1184,20 +1173,14 @@ static int dev_alloc_name_ns(struct net *net, int dev_alloc_name(struct net_device *dev, const char *name) { - return dev_alloc_name_ns(dev_net(dev), dev, name); + return __dev_alloc_name(dev_net(dev), name, dev->name); } EXPORT_SYMBOL(dev_alloc_name); static int dev_get_valid_name(struct net *net, struct net_device *dev, const char *name) { - char buf[IFNAMSIZ]; - int ret; - - ret = dev_prep_valid_name(net, dev, name, buf); - if (ret >= 0) - strscpy(dev->name, buf, IFNAMSIZ); - return ret; + return dev_prep_valid_name(net, dev, name, dev->name); } /**