| Message ID | 1515636190-24061-28-git-send-email-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/10/2018 06:02 PM, Kees Cook wrote: > From: David Windsor <dave@nullcore.net> > > The autoclose field can be copied with put_user(), so there is no need to > use copy_to_user(). In both cases, hardened usercopy is being bypassed > since the size is constant, and not open to runtime manipulation. > > This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY > whitelisting code in the last public patch of grsecurity/PaX based on my > understanding of the code. Changes or omissions from the original code are > mine and don't reflect the original grsecurity/PaX code. > Just tried a quick rebase and it looks like this conflicts with c76f97c99ae6 ("sctp: make use of pre-calculated len") I don't think we can use put_user if we're copying via the full len? Thanks, Laura > Signed-off-by: David Windsor <dave@nullcore.net> > [kees: adjust commit log] > Cc: Vlad Yasevich <vyasevich@gmail.com> > Cc: Neil Horman <nhorman@tuxdriver.com> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: linux-sctp@vger.kernel.org > Cc: netdev@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > net/sctp/socket.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index efbc8f52c531..15491491ec88 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -5011,7 +5011,7 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv > len = sizeof(int); > if (put_user(len, optlen)) > return -EFAULT; > - if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int))) > + if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval)) > return -EFAULT; > return 0; > } >
On Thu, Jan 18, 2018 at 1:31 PM, Laura Abbott <labbott@redhat.com> wrote: > On 01/10/2018 06:02 PM, Kees Cook wrote: >> >> From: David Windsor <dave@nullcore.net> >> >> The autoclose field can be copied with put_user(), so there is no need to >> use copy_to_user(). In both cases, hardened usercopy is being bypassed >> since the size is constant, and not open to runtime manipulation. >> >> This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY >> whitelisting code in the last public patch of grsecurity/PaX based on my >> understanding of the code. Changes or omissions from the original code are >> mine and don't reflect the original grsecurity/PaX code. >> > > Just tried a quick rebase and it looks like this conflicts with > c76f97c99ae6 ("sctp: make use of pre-calculated len") > I don't think we can use put_user if we're copying via the full > len? It should be fine, since: len = sizeof(int); c76f97c99ae6 just does a swap of sizeof(int) with len, put_user() will work in either case, since autoclose will always be int sized. -Kees > > Thanks, > Laura > > >> Signed-off-by: David Windsor <dave@nullcore.net> >> [kees: adjust commit log] >> Cc: Vlad Yasevich <vyasevich@gmail.com> >> Cc: Neil Horman <nhorman@tuxdriver.com> >> Cc: "David S. Miller" <davem@davemloft.net> >> Cc: linux-sctp@vger.kernel.org >> Cc: netdev@vger.kernel.org >> Signed-off-by: Kees Cook <keescook@chromium.org> >> --- >> net/sctp/socket.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/net/sctp/socket.c b/net/sctp/socket.c >> index efbc8f52c531..15491491ec88 100644 >> --- a/net/sctp/socket.c >> +++ b/net/sctp/socket.c >> @@ -5011,7 +5011,7 @@ static int sctp_getsockopt_autoclose(struct sock >> *sk, int len, char __user *optv >> len = sizeof(int); >> if (put_user(len, optlen)) >> return -EFAULT; >> - if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int))) >> + if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval)) >> return -EFAULT; >> return 0; >> } >> >
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index efbc8f52c531..15491491ec88 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -5011,7 +5011,7 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv len = sizeof(int); if (put_user(len, optlen)) return -EFAULT; - if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int))) + if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval)) return -EFAULT; return 0; }