sctp: use GFP_USER for user-controlled kmalloc
Dmitry Vyukov reported that the user could trigger a kernel warning by
using a large len value for getsockopt SCTP_GET_LOCAL_ADDRS, as that
value directly affects the value used as a kmalloc() parameter.
This patch thus switches the allocation flags from all user-controllable
kmalloc size to GFP_USER to put some more restrictions on it and also
disables the warn, as they are not necessary.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 5e35ef3..f6161e3 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -972,7 +972,7 @@
return -EFAULT;
/* Alloc space for the address array in kernel memory. */
- kaddrs = kmalloc(addrs_size, GFP_KERNEL);
+ kaddrs = kmalloc(addrs_size, GFP_USER | __GFP_NOWARN);
if (unlikely(!kaddrs))
return -ENOMEM;
@@ -4928,7 +4928,7 @@
to = optval + offsetof(struct sctp_getaddrs, addrs);
space_left = len - offsetof(struct sctp_getaddrs, addrs);
- addrs = kmalloc(space_left, GFP_KERNEL);
+ addrs = kmalloc(space_left, GFP_USER | __GFP_NOWARN);
if (!addrs)
return -ENOMEM;