From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Remi Pommarel <repk@triplefau.lt>,
        Arnd Bergmann <arnd@arndb.de>,
        Nikolay Aleksandrov <nikolay@nvidia.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 048/128] net: bridge: fix ioctl old_deviceless bridge argument
Date:   Mon, 27 Dec 2021 16:30:23 +0100
Message-Id: <20211227151333.120464482@linuxfoundation.org>
In-Reply-To: <20211227151331.502501367@linuxfoundation.org>
References: <20211227151331.502501367@linuxfoundation.org>
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From: Remi Pommarel <repk@triplefau.lt>

[ Upstream commit d95a56207c078e2019cf6659d890ec1e987e8420 ]

Commit 561d8352818f ("bridge: use ndo_siocdevprivate") changed the
source and destination arguments of copy_{to,from}_user in bridge's
old_deviceless() from args[1] to uarg breaking SIOC{G,S}IFBR ioctls.

Commit cbd7ad29a507 ("net: bridge: fix ioctl old_deviceless bridge
argument") fixed only BRCTL_{ADD,DEL}_BRIDGES commands leaving
BRCTL_GET_BRIDGES one untouched.

The fixes BRCTL_GET_BRIDGES as well and has been tested with busybox's
brctl.

Example of broken brctl:
$ brctl show
bridge name     bridge id               STP enabled     interfaces
brctl: can't get bridge name for index 0: No such device or address

Example of fixed brctl:
$ brctl show
bridge name     bridge id               STP enabled     interfaces
br0             8000.000000000000       no

Fixes: 561d8352818f ("bridge: use ndo_siocdevprivate")
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/all/20211223153139.7661-2-repk@triplefau.lt/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bridge/br_ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 49c268871fc11..9922497e59f8c 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -337,7 +337,7 @@ static int old_deviceless(struct net *net, void __user *uarg)
 
 		args[2] = get_bridge_ifindices(net, indices, args[2]);
 
-		ret = copy_to_user(uarg, indices,
+		ret = copy_to_user((void __user *)args[1], indices,
 				   array_size(args[2], sizeof(int)))
 			? -EFAULT : args[2];
 
-- 
2.34.1