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Commit cacc0621 authored by Marcelo Ricardo Leitner's avatar Marcelo Ricardo Leitner Committed by David S. Miller
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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: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 38ee8fb6

net/sctp/socket.c

+2 −2
Original line number Diff line number Diff line
@@ -972,7 +972,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, 
		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 @@ static int sctp_getsockopt_local_addrs(struct sock *sk, int len, 
	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;