| Message ID | 20170425165146.25075-1-glider@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Alexander Potapenko <glider@google.com> Date: Tue, 25 Apr 2017 18:51:46 +0200 > 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> Applied, thanks.
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 8489beff5c25..ea81ccf3c7d6 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3836,6 +3836,8 @@ 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) {
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> --- The previous versions of this patch were called "net/packet: initialize val in packet_getsockopt()" v3: - change patch summary, return -EINVAL for optlen < sizeof(int) v2: - if len < sizeof(int), make it 0 --- net/packet/af_packet.c | 2 ++ 1 file changed, 2 insertions(+)