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authorAlexander Potapenko <glider@google.com>2017-04-25 18:51:46 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-10-08 10:26:08 +0200
commit897e8c528529f5b53d1a63bbac3802adf5e09170 (patch)
tree240d5fd8a5a70e4e29d7646c268337dcfde66fde /net/packet
parent1dee03af7325f8a04954f9114cb76945fddb950c (diff)
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 35ba4b60d927..9c92c6cb6a4f 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3884,6 +3884,8 @@ 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) {