From 3de8ae6c0d1c0fb73243992adf87c7174028a531 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Thu, 21 Jul 2011 15:25:30 -0700 Subject: [PATCH 560/696] ethtool: Allow zero-length register dumps again commit 67ae7cf1eeda777f79259c4c6cb17a0bd28dee71 upstream. Some drivers (ab)use the ethtool_ops::get_regs operation to expose only a hardware revision ID. Commit a77f5db361ed9953b5b749353ea2c7fed2bf8d93 ('ethtool: Allocate register dump buffer with vmalloc()') had the side-effect of breaking these, as vmalloc() returns a null pointer for size=0 whereas kmalloc() did not. For backward-compatibility, allow zero-length dumps again. Reported-by: Kalle Valo Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/ethtool.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/ethtool.c b/net/core/ethtool.c index fd14116..4fb7704 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1227,7 +1227,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) regs.len = reglen; regbuf = vzalloc(reglen); - if (!regbuf) + if (reglen && !regbuf) return -ENOMEM; ops->get_regs(dev, ®s, regbuf); @@ -1236,7 +1236,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) if (copy_to_user(useraddr, ®s, sizeof(regs))) goto out; useraddr += offsetof(struct ethtool_regs, data); - if (copy_to_user(useraddr, regbuf, regs.len)) + if (regbuf && copy_to_user(useraddr, regbuf, regs.len)) goto out; ret = 0; -- 1.7.1