Messages in this thread | | | Date | Tue, 01 Dec 2015 12:29:40 +0100 | From | Daniel Borkmann <> | Subject | Re: [PATCH] sctp: use GFP_USER for user-controlled kmalloc |
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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.
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