From patchwork Mon May 6 14:08:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Duoming Zhou X-Patchwork-Id: 13655517 X-Patchwork-Delegate: kuba@kernel.org Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [52.237.72.81]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 54F8E83A0A; Mon, 6 May 2024 14:09:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.237.72.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715004561; cv=none; b=slM9ujUC2yyOsqxOu8dqkNb56egch/RzyfIRvy6dHNw9fU+ScVaW6MeDz4UX7DeWtpeHAwWDHRzT8LqGtoPafLYEOjCte8iT0GvOZTIeqmhEdz8fqhbKRpSZBabbhjRtBcKk18zaX0t9/No8OfJebptU/N6gHhUjbIQrIvUGSp0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715004561; c=relaxed/simple; bh=Ybv9SpHx2OiiP79Oeh18r5QaGZGa6GjkoLYnEg8H4tU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: In-Reply-To:References; b=Suk8wtwDnJyBFXyMHuFXAf3ImrvWnljzF16GQm0N9e10bsa73X5ttYUerITRjYLbRd1hIG9S8HRQo775RAyT0SvqE4CpJafpmC9BVPS6/UfBCZu4Ao1UynUh768QLHGAx4oRMZT5VS0CNrL7wR/Xx+c4mSpOFAGFNIkiq4m6jag= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn; spf=pass smtp.mailfrom=zju.edu.cn; arc=none smtp.client-ip=52.237.72.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zju.edu.cn Received: from ubuntu.localdomain (unknown [221.192.180.207]) by mail-app2 (Coremail) with SMTP id by_KCgCXtaRj5DhmI_s4AA--.15255S3; Mon, 06 May 2024 22:08:42 +0800 (CST) From: Duoming Zhou To: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-hams@vger.kernel.org, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, davem@davemloft.net, jreuter@yaina.de, horms@kernel.org, Markus.Elfring@web.de, dan.carpenter@linaro.org, lars@oddbit.com, Duoming Zhou Subject: [PATCH net v3 1/2] ax25: Fix reference count leak issues of ax25_dev and net_device Date: Mon, 6 May 2024 22:08:34 +0800 Message-Id: <8338a74098bc1aafbca14d4612a10d6930fcef1b.1715002910.git.duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: X-CM-TRANSID: by_KCgCXtaRj5DhmI_s4AA--.15255S3 X-Coremail-Antispam: 1UD129KBjvJXoW3JrWDXr45trW5Cr48KF48WFg_yoW7Cr1UpF Wa9FyrArZ7Jr1UAr4DWF1xGr1jyryjkws5Ary5uF1Ikw15X3sxJr18tr1DJryUGrW3ZF18 J347Wrs8Ar48uw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmK14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE14v_Xryl42xK82IYc2Ij64vIr41l4I8I 3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxV WUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAF wI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcI k0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j 6r4UJbIYCTnIWIevJa73UjIFyTuYvjfU1MKZDUUUU X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAwINAWY3qokcfgAbsG Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: X-Patchwork-Delegate: kuba@kernel.org The ax25_addr_ax25dev() exists a reference count leak issue of the object "ax25_dev" and the ax25_dev_device_down() exists reference count leak issues of the objects "ax25_dev" and "net_device". Memory leak issue in ax25_addr_ax25dev(): The reference count of the object "ax25_dev" can be increased multiple times in ax25_addr_ax25dev(). This will cause a memory leak so far. Memory leak issues in ax25_dev_device_down(): The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and then increase the reference count when ax25_dev is added to ax25_dev_list. As a result, the reference count of ax25_dev is 2. But when the device is shutting down. The ax25_dev_device_down() drops the reference count once or twice depending on if we goto unlock_put or not, which will cause memory leak. There is also a reference count leak issue of the object "net_device", when the ax25 device is shutting down. The ax25_dev_device_down() drops the reference count of net_device one or zero times depending on if we goto unlock_put or not, which will cause memory leak. In order to solve the above issues, use kernel circular doubly linked list to implementate ax25_dev_list. As for ax25_addr_ax25dev() issue, it is impossible for one pointer to be on a list twice. So add a break in ax25_addr_ax25dev(). As for ax25_dev_device_down() issues, increase the reference count of ax25_dev once in ax25_dev_device_up() and decrease the reference count of ax25_dev and net_device after ax25_dev is removed from the ax25_dev_list. Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs") Suggested-by: Dan Carpenter Signed-off-by: Duoming Zhou --- Changes in v3: - Use kernel list to implementate ax25_dev_list. - Solve reference count leak issues in ax25_dev_device_down(). include/net/ax25.h | 4 ++-- net/ax25/ax25_dev.c | 36 ++++++++++++------------------------ 2 files changed, 14 insertions(+), 26 deletions(-) diff --git a/include/net/ax25.h b/include/net/ax25.h index 0d939e5aee4..92c6aa4f9a6 100644 --- a/include/net/ax25.h +++ b/include/net/ax25.h @@ -216,7 +216,7 @@ typedef struct { struct ctl_table; typedef struct ax25_dev { - struct ax25_dev *next; + struct list_head list; struct net_device *dev; netdevice_tracker dev_tracker; @@ -330,7 +330,7 @@ int ax25_addr_size(const ax25_digi *); void ax25_digi_invert(const ax25_digi *, ax25_digi *); /* ax25_dev.c */ -extern ax25_dev *ax25_dev_list; +static struct list_head ax25_dev_list; extern spinlock_t ax25_dev_lock; #if IS_ENABLED(CONFIG_AX25) diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c index 282ec581c07..fbaaba0351e 100644 --- a/net/ax25/ax25_dev.c +++ b/net/ax25/ax25_dev.c @@ -22,11 +22,11 @@ #include #include #include +#include #include #include #include -ax25_dev *ax25_dev_list; DEFINE_SPINLOCK(ax25_dev_lock); ax25_dev *ax25_addr_ax25dev(ax25_address *addr) @@ -34,11 +34,13 @@ ax25_dev *ax25_addr_ax25dev(ax25_address *addr) ax25_dev *ax25_dev, *res = NULL; spin_lock_bh(&ax25_dev_lock); - for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next) + list_for_each_entry(ax25_dev, &ax25_dev_list, list) { if (ax25cmp(addr, (const ax25_address *)ax25_dev->dev->dev_addr) == 0) { res = ax25_dev; ax25_dev_hold(ax25_dev); + break; } + } spin_unlock_bh(&ax25_dev_lock); return res; @@ -52,6 +54,7 @@ void ax25_dev_device_up(struct net_device *dev) { ax25_dev *ax25_dev; + INIT_LIST_HEAD(&ax25_dev_list); ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_KERNEL); if (!ax25_dev) { printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n"); @@ -59,7 +62,6 @@ void ax25_dev_device_up(struct net_device *dev) } refcount_set(&ax25_dev->refcount, 1); - dev->ax25_ptr = ax25_dev; ax25_dev->dev = dev; netdev_hold(dev, &ax25_dev->dev_tracker, GFP_KERNEL); ax25_dev->forward = NULL; @@ -85,10 +87,9 @@ void ax25_dev_device_up(struct net_device *dev) #endif spin_lock_bh(&ax25_dev_lock); - ax25_dev->next = ax25_dev_list; - ax25_dev_list = ax25_dev; + list_add(&ax25_dev->list, &ax25_dev_list); spin_unlock_bh(&ax25_dev_lock); - ax25_dev_hold(ax25_dev); + dev->ax25_ptr = ax25_dev; ax25_register_dev_sysctl(ax25_dev); } @@ -111,32 +112,19 @@ void ax25_dev_device_down(struct net_device *dev) /* * Remove any packet forwarding that points to this device. */ - for (s = ax25_dev_list; s != NULL; s = s->next) + list_for_each_entry(s, &ax25_dev_list, list) { if (s->forward == dev) s->forward = NULL; - - if ((s = ax25_dev_list) == ax25_dev) { - ax25_dev_list = s->next; - goto unlock_put; } - while (s != NULL && s->next != NULL) { - if (s->next == ax25_dev) { - s->next = ax25_dev->next; - goto unlock_put; + list_for_each_entry(s, &ax25_dev_list, list) { + if (s == ax25_dev) { + list_del(&s->list); + break; } - - s = s->next; } - spin_unlock_bh(&ax25_dev_lock); dev->ax25_ptr = NULL; - ax25_dev_put(ax25_dev); - return; - -unlock_put: spin_unlock_bh(&ax25_dev_lock); - ax25_dev_put(ax25_dev); - dev->ax25_ptr = NULL; netdev_put(dev, &ax25_dev->dev_tracker); ax25_dev_put(ax25_dev); }