| Message ID | db23659cdf84bc80aff45e906cbfb67581e7a125.1448901154.git.marcelo.leitner@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Marcelo Ricardo Leitner > Sent: 30 November 2015 16:33 > 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. ISTM that the code should put some 'sanity limit' on that size before allocating the kernel buffer. David -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/01/2015 11:46 AM, David Laight wrote: > From: Marcelo Ricardo Leitner >> Sent: 30 November 2015 16:33 >> 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. > > ISTM that the code should put some 'sanity limit' on that > size before allocating the kernel buffer. One could do that in addition, but this buffer has just a short lifetime and by using GFP_USER hardwall restrictions apply already. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Date: Mon, 30 Nov 2015 14:32:54 -0200 > 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> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 897c01c029cab3d5805cc56b0964c70e06f4143a..676b3bb092e16848fd1c822e1c999af4a2ef198d 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -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;