diff options
| author | Wenwen Wang <wang6495@umn.edu> | 2018-10-18 09:36:46 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 07:41:41 -0800 |
| commit | 98528072a2a9f7936bb2cbda6bf0f34545a45adf (patch) | |
| tree | 67f21a394a0a3e986451b47d2b6a7ed6ef1295ea /net/socket.c | |
| parent | 7fc851d0f813c939e72f26d37bd8cd876abc8241 (diff) | |
net: socket: fix a missing-check bug
[ Upstream commit b6168562c8ce2bd5a30e213021650422e08764dc ]
In ethtool_ioctl(), the ioctl command 'ethcmd' is checked through a switch
statement to see whether it is necessary to pre-process the ethtool
structure, because, as mentioned in the comment, the structure
ethtool_rxnfc is defined with padding. If yes, a user-space buffer 'rxnfc'
is allocated through compat_alloc_user_space(). One thing to note here is
that, if 'ethcmd' is ETHTOOL_GRXCLSRLALL, the size of the buffer 'rxnfc' is
partially determined by 'rule_cnt', which is actually acquired from the
user-space buffer 'compat_rxnfc', i.e., 'compat_rxnfc->rule_cnt', through
get_user(). After 'rxnfc' is allocated, the data in the original user-space
buffer 'compat_rxnfc' is then copied to 'rxnfc' through copy_in_user(),
including the 'rule_cnt' field. However, after this copy, no check is
re-enforced on 'rxnfc->rule_cnt'. So it is possible that a malicious user
race to change the value in the 'compat_rxnfc->rule_cnt' between these two
copies. Through this way, the attacker can bypass the previous check on
'rule_cnt' and inject malicious data. This can cause undefined behavior of
the kernel and introduce potential security risk.
This patch avoids the above issue via copying the value acquired by
get_user() to 'rxnfc->rule_cn', if 'ethcmd' is ETHTOOL_GRXCLSRLALL.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/socket.c')
| -rw-r--r-- | net/socket.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/socket.c b/net/socket.c index 0c544ae48eac..96133777d17c 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2760,9 +2760,14 @@ static int ethtool_ioctl(struct net *net, struct compat_ifreq __user *ifr32) copy_in_user(&rxnfc->fs.ring_cookie, &compat_rxnfc->fs.ring_cookie, (void __user *)(&rxnfc->fs.location + 1) - - (void __user *)&rxnfc->fs.ring_cookie) || - copy_in_user(&rxnfc->rule_cnt, &compat_rxnfc->rule_cnt, - sizeof(rxnfc->rule_cnt))) + (void __user *)&rxnfc->fs.ring_cookie)) + return -EFAULT; + if (ethcmd == ETHTOOL_GRXCLSRLALL) { + if (put_user(rule_cnt, &rxnfc->rule_cnt)) + return -EFAULT; + } else if (copy_in_user(&rxnfc->rule_cnt, + &compat_rxnfc->rule_cnt, + sizeof(rxnfc->rule_cnt))) return -EFAULT; } |