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[35.245.174.172]) by smtp.gmail.com with ESMTPSA id x12-20020ae9f80c000000b007623d5d7c59sm1076438qkh.94.2023.06.20.06.15.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jun 2023 06:15:39 -0700 (PDT) Date: Tue, 20 Jun 2023 09:15:39 -0400 From: Willem de Bruijn To: David Ahern , Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, syzbot , Breno Leitao , Willem de Bruijn , Kuniyuki Iwashima Message-ID: <6491a67b7b9e1_3bcfec29439@willemb.c.googlers.com.notmuch> In-Reply-To: <483161ce-f36b-a0d8-0239-6c68ea34e92f@kernel.org> References: <20230619124336.651528-1-edumazet@google.com> <483161ce-f36b-a0d8-0239-6c68ea34e92f@kernel.org> Subject: Re: [PATCH net-next] net: remove sk_is_ipmr() and sk_is_icmpv6() helpers Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net David Ahern wrote: > On 6/19/23 5:43 AM, Eric Dumazet wrote: > > Blamed commit added these helpers for sake of detecting RAW > > sockets specific ioctl. > > > > syzbot complained about it [1]. > > > > Issue here is that RAW sockets could pretend there was no need > > to call ipmr_sk_ioctl() > > > > Regardless of inet_sk(sk)->inet_num, we must be prepared > > for ipmr_ioctl() being called later. This must happen > > from ipmr_sk_ioctl() context only. > > > > We could add a safety check in ipmr_ioctl() at the risk of breaking > > applications. > > > > Instead, remove sk_is_ipmr() and sk_is_icmpv6() because their > > name would be misleading, once we change their implementation. > > > > [1] > > BUG: KASAN: stack-out-of-bounds in ipmr_ioctl+0xb12/0xbd0 net/ipv4/ipmr.c:1654 > > Read of size 4 at addr ffffc90003aefae4 by task syz-executor105/5004 > > > > CPU: 0 PID: 5004 Comm: syz-executor105 Not tainted 6.4.0-rc6-syzkaller-01304-gc08afcdcf952 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 > > print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 > > print_report mm/kasan/report.c:462 [inline] > > kasan_report+0x11c/0x130 mm/kasan/report.c:572 > > ipmr_ioctl+0xb12/0xbd0 net/ipv4/ipmr.c:1654 > > raw_ioctl+0x4e/0x1e0 net/ipv4/raw.c:881 > > sock_ioctl_out net/core/sock.c:4186 [inline] > > sk_ioctl+0x151/0x440 net/core/sock.c:4214 > > inet_ioctl+0x18c/0x380 net/ipv4/af_inet.c:1001 > > sock_do_ioctl+0xcc/0x230 net/socket.c:1189 > > sock_ioctl+0x1f8/0x680 net/socket.c:1306 > > vfs_ioctl fs/ioctl.c:51 [inline] > > __do_sys_ioctl fs/ioctl.c:870 [inline] > > __se_sys_ioctl fs/ioctl.c:856 [inline] > > __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > RIP: 0033:0x7f2944bf6ad9 > > Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 > > RSP: 002b:00007ffd8897a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2944bf6ad9 > > RDX: 0000000000000000 RSI: 00000000000089e1 RDI: 0000000000000003 > > RBP: 00007f2944bbac80 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2944bbad10 > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > > > > > > The buggy address belongs to stack of task syz-executor105/5004 > > and is located at offset 36 in frame: > > sk_ioctl+0x0/0x440 net/core/sock.c:4172 > > > > This frame has 2 objects: > > [32, 36) 'karg' > > [48, 88) 'buffer' > > > > Fixes: e1d001fa5b47 ("net: ioctl: Use kernel memory on protocol ioctl callbacks") > > Reported-by: syzbot > > Signed-off-by: Eric Dumazet > > Cc: Breno Leitao > > Cc: Willem de Bruijn > > Cc: David Ahern > > Cc: Kuniyuki Iwashima > > --- > > include/linux/icmpv6.h | 6 ------ > > include/linux/mroute.h | 11 ----------- > > net/core/sock.c | 4 ++-- > > 3 files changed, 2 insertions(+), 19 deletions(-) > > > > diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h > > index 1fe33e6741cca2685082da214afbc94c7974f4ce..db0f4fcfdaf4f138d75dc6c4073cb286364f2923 100644 > > --- a/include/linux/icmpv6.h > > +++ b/include/linux/icmpv6.h > > @@ -111,10 +111,4 @@ static inline bool icmpv6_is_err(int type) > > return false; > > } > > > > -static inline int sk_is_icmpv6(struct sock *sk) > > -{ > > - return sk->sk_family == AF_INET6 && > > - inet_sk(sk)->inet_num == IPPROTO_ICMPV6; > > -} > > - > > #endif > > diff --git a/include/linux/mroute.h b/include/linux/mroute.h > > index 94c6e6f549f0a503f6707d1175f1c47a0f0cd887..4c5003afee6c51962bc13879978845bc7daf08fa 100644 > > --- a/include/linux/mroute.h > > +++ b/include/linux/mroute.h > > @@ -16,12 +16,6 @@ static inline int ip_mroute_opt(int opt) > > return opt >= MRT_BASE && opt <= MRT_MAX; > > } > > > > -static inline int sk_is_ipmr(struct sock *sk) > > -{ > > - return sk->sk_family == AF_INET && > > - inet_sk(sk)->inet_num == IPPROTO_IGMP; > > -} > > - > > int ip_mroute_setsockopt(struct sock *, int, sockptr_t, unsigned int); > > int ip_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t); > > int ipmr_ioctl(struct sock *sk, int cmd, void *arg); > > @@ -57,11 +51,6 @@ static inline int ip_mroute_opt(int opt) > > return 0; > > } > > > > -static inline int sk_is_ipmr(struct sock *sk) > > -{ > > - return 0; > > -} > > - > > static inline bool ipmr_rule_default(const struct fib_rule *rule) > > { > > return true; > > diff --git a/net/core/sock.c b/net/core/sock.c > > index cff3e82514d17513bc96300dc18014083a0d7ea7..8ec8f4c9911f2a6dd3dd946798d512394d62a861 100644 > > --- a/net/core/sock.c > > +++ b/net/core/sock.c > > @@ -4199,9 +4199,9 @@ int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg) > > { > > int rc = 1; > > > > - if (sk_is_ipmr(sk)) > > + if (sk->sk_type == SOCK_RAW && sk->sk_family == AF_INET) > > rc = ipmr_sk_ioctl(sk, cmd, arg); > > - else if (sk_is_icmpv6(sk)) > > + else if (sk->sk_type == SOCK_RAW && sk->sk_family == AF_INET6) > > rc = ip6mr_sk_ioctl(sk, cmd, arg); > > else if (sk_is_phonet(sk)) > > rc = phonet_sk_ioctl(sk, cmd, arg); > > I was staring at the type when reviewing the original patch; I was > expecting to see RAW based on where ipmr_ioctl (and v6 version) is > called. That's why I asked about the testing of the patch, so I am not > surprised by this followup. > > Reviewed-by: David Ahern ipmr_ioctl is called from raw_ioctl without any additional checks on inet_sk(sk)->inet_num too (as are ip6mr_ioctl and ipmr_compat_ioctl), and casts to raw_sk(sk) without further checks. So this condition lgtm too. And conversely, interpreting inet_num(sk) as a protocol is only okay after testing sk_type == SOCK_RAW. Thanks for the fix, Eric Reviewed-by: Willem de Bruijn