Messages in this thread | | | Date | Thu, 7 Jun 2018 14:28:31 -0600 | From | Tycho Andersen <> | Subject | Re: [PATCH] dh key: fix rounding up KDF output length |
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On Thu, Jun 07, 2018 at 12:12:01PM -0700, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > Commit 383203eff718 ("dh key: get rid of stack allocated array") changed > kdf_ctr() to assume that the length of key material to derive is a > multiple of the digest size. The length was supposed to be rounded up > accordingly. However, the round_up() macro was used which only gives > the correct result on power-of-2 arguments, whereas not all hash > algorithms have power-of-2 digest sizes. In some cases this resulted in > a write past the end of the 'outbuf' buffer. > > Fix it by switching to roundup(), which works for non-power-of-2 inputs. > > Reported-by: syzbot+486f97f892efeb2075a3@syzkaller.appspotmail.com > Reported-by: syzbot+29d17b7898b41ee120a5@syzkaller.appspotmail.com > Reported-by: syzbot+8a608baf8751184ec727@syzkaller.appspotmail.com > Reported-by: syzbot+d04e58bd384f1fe0b112@syzkaller.appspotmail.com > Fixes: 383203eff718 ("dh key: get rid of stack allocated array") > Signed-off-by: Eric Biggers <ebiggers@google.com>
Arg, thanks.
Acked-by: Tycho Andersen <tycho@tycho.ws>
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