[PATCH] ethtool: fix ethtool_get_regs() to work with zero length registers
From: Kalle Valo <hidden>
Date: 2011-07-20 09:18:50
Also in:
linux-wireless
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
cfg80211 exports zero length register size as it currently only uses struct ethtool_regs.version to export struct wiphy.hw_version. But the problem is that ethtool_get_regs() assumes that the driver (cfg80211 in this case) always has non-zero length for registers. With cfg80211 it would always fail and return -ENOMEM to user space. Fix this by checking the register length from the driver and exporting struct ethtool_regs to user space if the length is zero. With this patch it's possible to get the hardware id from wireless drivers. Tested with wl12xx and ath6kl. Tested-by: Gery Kahn <redacted> Signed-off-by: Kalle Valo <redacted> --- net/core/ethtool.c | 20 +++++++++++++------- 1 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index fd14116..6f073f4 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c@@ -1213,7 +1213,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) { struct ethtool_regs regs; const struct ethtool_ops *ops = dev->ethtool_ops; - void *regbuf; + void *regbuf = NULL; int reglen, ret; if (!ops->get_regs || !ops->get_regs_len)
@@ -1226,18 +1226,24 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) if (regs.len > reglen) regs.len = reglen; - regbuf = vzalloc(reglen); - if (!regbuf) - return -ENOMEM; + if (reglen > 0) { + regbuf = vzalloc(reglen); + if (!regbuf) + return -ENOMEM; + } ops->get_regs(dev, ®s, regbuf); ret = -EFAULT; if (copy_to_user(useraddr, ®s, sizeof(regs))) goto out; - useraddr += offsetof(struct ethtool_regs, data); - if (copy_to_user(useraddr, regbuf, regs.len)) - goto out; + + if (regs.len > 0) { + useraddr += offsetof(struct ethtool_regs, data); + if (copy_to_user(useraddr, regbuf, regs.len)) + goto out; + } + ret = 0; out: --
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