Messages in this thread | | | Subject | Re: [PATCH] inet: sanitize socket() protocol value | From | Vegard Nossum <> | Date | Thu, 17 Dec 2015 02:05:01 +0100 |
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On 12/17/2015 02:01 AM, Eric Dumazet wrote: > On Wed, Dec 16, 2015 at 4:57 PM, Vegard Nossum <vegard.nossum@oracle.com> wrote: >> If you create a raw socket with a protocol of e.g. 0x10000, then >> inet_sk(sk)->inet_num will get set to 0 since it only has room for 16 >> bits. This causes problems further down the line as lots of code makes >> assumptions about ->inet_num, for example connect()...inet_autobind() >> will attempt to call sk->sk_prot->get_port() which is invalid: >> >> BUG: unable to handle kernel NULL pointer dereference at (null) >> IP: [< (null)>] (null) >> PGD 19ea0067 PUD 19d3f067 PMD 0 >> Oops: 0010 [#1] SMP >> CPU: 1 PID: 849 Comm: a.out Not tainted 4.4.0-rc4+ #287 >> task: ffff880019a12640 ti: ffff88000008c000 task.ti: ffff88000008c000 >> RIP: 0010:[<0000000000000000>] [< (null)>] (null) >> RSP: 0018:ffff88000008fe50 EFLAGS: 00010246 >> RAX: ffffffff81cc61f0 RBX: ffff880019d2ca80 RCX: 0000000000000802 >> RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff880019d2ca80 >> RBP: ffff88000008fe60 R08: 00007f0e6b132e80 R09: ffff880019d2ca80 >> R10: ffff88001a7a72e0 R11: ffff880019a12640 R12: 000000000000000b >> R13: 0000000000400644 R14: 0000000000000000 R15: 0000000000000000 >> FS: 00007f0e6b355740(0000) GS:ffff88001a900000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000000000000000 CR3: 0000000019d3d000 CR4: 00000000001406a0 >> Stack: >> ffffffff815f1c69 ffff880019d2ca80 ffff88000008fe88 ffffffff815f1cde >> 0000000b0000000b ffff88000008fea0 ffff880019484000 ffff88000008ff38 >> ffffffff8156f310 0000000000000000 2a2a2a2a2a2a2a2a ffffffff8100002a >> Call Trace: >> [<ffffffff815f1c69>] ? inet_autobind+0x23/0x50 >> [<ffffffff815f1cde>] inet_dgram_connect+0x48/0x64 >> [<ffffffff8156f310>] SYSC_connect+0x84/0xae >> [<ffffffff8156f3ed>] ? sock_alloc_file+0xb3/0x108 >> [<ffffffff81132021>] ? fd_install+0x20/0x22 >> [<ffffffff815700d2>] ? SYSC_socket+0x62/0x90 >> [<ffffffff81570318>] SyS_connect+0x9/0xb >> [<ffffffff816fb86e>] entry_SYSCALL_64_fastpath+0x12/0x71 >> Code: Bad RIP value. >> RIP [< (null)>] (null) >> RSP <ffff88000008fe50> >> CR2: 0000000000000000 >> ---[ end trace bd60b4fe2edc2537 ]--- >> >> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> >> Cc: Eric Dumazet <edumazet@google.com> >> Cc: <stable@vger.kernel.org> >> --- >> net/ipv4/af_inet.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git net/ipv4/af_inet.c net/ipv4/af_inet.c >> index 11c4ca1..4e1583a 100644 >> --- net/ipv4/af_inet.c >> +++ net/ipv4/af_inet.c >> @@ -316,6 +316,12 @@ lookup_protocol: >> >> WARN_ON(!answer_prot->slab); >> >> + /* Check that the protocol we were given will actually fit in >> + * inet->inet_num. */ >> + err = -EINVAL; >> + if (protocol != (typeof(inet->inet_num)) protocol) >> + goto out; >> + >> err = -ENOBUFS; >> sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot, kern); >> if (!sk) >> -- >> 1.9.1 >> > > It looks already fixed in a better way (IPv6, ...) > > http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=79462ad02e861803b3840cc782248c7359451cd9
Ha, sorry, I missed that!
Thanks for the quick response.
Vegard
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