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authorAlexander Potapenko <glider@google.com>2017-04-25 19:51:46 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-10-08 11:14:18 +0300
commitfa63895f47c9253a0305a5d0862e98ab6f11e718 (patch)
treeea7d82fce77c6190a6fdab11cecb599902133f3e /net/packet
parentb9ff317b5cd4a8f7ca13934af679e129c3f1d2ce (diff)
downloadlinux-fa63895f47c9253a0305a5d0862e98ab6f11e718.tar.xz
net/packet: check length in getsockopt() called with PACKET_HDRLEN
[ Upstream commit fd2c83b35752f0a8236b976978ad4658df14a59f ] In the case getsockopt() is called with PACKET_HDRLEN and optlen < 4 |val| remains uninitialized and the syscall may behave differently depending on its value, and even copy garbage to userspace on certain architectures. To fix this we now return -EINVAL if optlen is too small. This bug has been detected with KMSAN. Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 148ec130d99d..b70055fc30cb 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3802,6 +3802,8 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
case PACKET_HDRLEN:
if (len > sizeof(int))
len = sizeof(int);
+ if (len < sizeof(int))
+ return -EINVAL;
if (copy_from_user(&val, optval, len))
return -EFAULT;
switch (val) {