Subject: Re: [PATCH] net: Fix invalid ip_route_output_ports() call

From: Hyunwoo Kim <[email-masked]>
Date: Tue, 21 Mar 2023 04:35:09 -0700

On Tue, Mar 21, 2023 at 04:19:25AM -0700, Eric Dumazet wrote:
> On Tue, Mar 21, 2023 at 4:14 AM Hyunwoo Kim <[email-masked]> wrote:
> >
> > I'm not sure what 'ip x p' means, as my understanding of XFRM is limited, sorry.
> 
> Since your repro does not set up a private netns.
> 
> Please install the iproute2 package (if not there already) and run the
> following command
> 
> sudo ip x p
> 
> man ip
> 
> IP(8)                                      Linux
>                IP(8)
> 
> NAME
>        ip - show / manipulate routing, network devices, interfaces and tunnels
> 
> SYNOPSIS

This is the result of creating a new netns, running repro, and then running the ip x p command:
```
src 255.1.0.0/0 dst 0.0.0.0/0
	dir out priority 0
	mark 0/0x6
	tmpl src 0.0.0.0 dst 0.0.0.0
		proto comp reqid 0 mode beet
		level 16
	tmpl src fc00:: dst e000:2::
		proto ah reqid 0 mode tunnel
		level 32
	tmpl src ac14:14bb:: dst ac14:14fa::
		proto route2 reqid 0 mode transport
		level 3
	tmpl src :: dst 2001::1
		proto ah reqid 0 mode in_trigger
	tmpl src ff01::1 dst 7f00:1::
		proto comp reqid 0 mode transport
```

> 
> >
> > Instead, here is the (dirty) code I used to trigger this:
> > ```
> > #include <endian.h>
> > #include <stdint.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <string.h>
> > #include <sys/syscall.h>
> > #include <sys/types.h>
> > #include <unistd.h>
> > #include <sched.h>
> > #include <fcntl.h>
> >
> >
> > uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};
> >
> > int main(void)
> > {
> >         int ret;
> >         intptr_t res = 0;
> >
> >         syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
> >         syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
> >         syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
> >
> >         res = syscall(__NR_socket, 0x10ul, 3ul, 0);
> >         printf("socket() 1 : %ld\n", res);
> >         if (res != -1)
> >                 r[0] = res;
> >         *(uint64_t*)0x20000000 = 0;
> >         *(uint32_t*)0x20000008 = 0;
> >         *(uint64_t*)0x20000010 = 0x20000140;
> >         *(uint64_t*)0x20000140 = 0x20000040;
> >         memcpy((void*)0x20000040,
> >                         "\x3c\x00\x00\x00\x10\x00\x01\x04\x00\xee\xff\xff\xff\xff\xff\xff\x00"
> >                         "\x00\x00\x00",
> >                         20);
> >         *(uint32_t*)0x20000054 = -1;
> >         memcpy((void*)0x20000058,
> >                         "\x01\x00\x00\x00\x01\x00\x00\x00\x1c\x00\x12\x00\x0c\x00\x01\x00\x62"
> >                         "\x72\x69\x64\x67\x65",
> >                         22);
> >         *(uint64_t*)0x20000148 = 0x3c;
> >         *(uint64_t*)0x20000018 = 1;
> >         *(uint64_t*)0x20000020 = 0;
> >         *(uint64_t*)0x20000028 = 0;
> >         *(uint32_t*)0x20000030 = 0;
> >         ret = syscall(__NR_sendmsg, r[0], 0x20000000ul, 0ul);
> >         printf("sendmsg() 1 : %d\n", ret);
> >
> >         res = syscall(__NR_socket, 0x10ul, 3ul, 6);
> >         printf("socket() 2 : %ld\n", res);
> >         if (res != -1)
> >                 r[1] = res;
> >         *(uint64_t*)0x20000480 = 0;
> >         *(uint32_t*)0x20000488 = 0;
> >         *(uint64_t*)0x20000490 = 0x20000200;
> >         *(uint64_t*)0x20000200 = 0x200004c0;
> >         *(uint32_t*)0x200004c0 = 0x208;
> >         *(uint16_t*)0x200004c4 = 0x19;
> >         *(uint16_t*)0x200004c6 = 1;
> >         *(uint32_t*)0x200004c8 = 0;
> >         *(uint32_t*)0x200004cc = 0;
> >         memset((void*)0x200004d0, 0, 16);
> >         *(uint8_t*)0x200004e0 = -1;
> >         *(uint8_t*)0x200004e1 = 1;
> >         memset((void*)0x200004e2, 0, 13);
> >         *(uint8_t*)0x200004ef = 1;
> >         *(uint16_t*)0x200004f0 = htobe16(0);
> >         *(uint16_t*)0x200004f2 = htobe16(0);
> >         *(uint16_t*)0x200004f4 = htobe16(0);
> >         *(uint16_t*)0x200004f6 = htobe16(0);
> >         *(uint16_t*)0x200004f8 = 2;
> >         *(uint8_t*)0x200004fa = 0;
> >         *(uint8_t*)0x200004fb = 0;
> >         *(uint8_t*)0x200004fc = 0;
> >         *(uint32_t*)0x20000500 = 0;
> >         *(uint32_t*)0x20000504 = -1;
> >         *(uint64_t*)0x20000508 = 0;
> >         *(uint64_t*)0x20000510 = 0;
> >         *(uint64_t*)0x20000518 = 0;
> >         *(uint64_t*)0x20000520 = 0;
> >         *(uint64_t*)0x20000528 = 0;
> >         *(uint64_t*)0x20000530 = 0;
> >         *(uint64_t*)0x20000538 = 0;
> >         *(uint64_t*)0x20000540 = 0;
> >         *(uint64_t*)0x20000548 = 0;
> >         *(uint64_t*)0x20000550 = 0;
> >         *(uint64_t*)0x20000558 = 0;
> >         *(uint64_t*)0x20000560 = 0;
> >         *(uint32_t*)0x20000568 = 0;
> >         *(uint32_t*)0x2000056c = 0;
> >         *(uint8_t*)0x20000570 = 1;
> >         *(uint8_t*)0x20000571 = 0;
> >         *(uint8_t*)0x20000572 = 0;
> >         *(uint8_t*)0x20000573 = 0;
> >         *(uint16_t*)0x20000578 = 0xc;
> >         *(uint16_t*)0x2000057a = 0x15;
> >         *(uint32_t*)0x2000057c = 0;
> >         *(uint32_t*)0x20000580 = 6;
> >         *(uint16_t*)0x20000584 = 0x144;
> >         *(uint16_t*)0x20000586 = 5;
> >         memset((void*)0x20000588, 0, 16);
> >         *(uint32_t*)0x20000598 = htobe32(0);
> >         *(uint8_t*)0x2000059c = 0x6c;
> >         *(uint16_t*)0x200005a0 = 0;
> >         *(uint32_t*)0x200005a4 = htobe32(0);
> >         *(uint32_t*)0x200005b4 = 0;
> >         *(uint8_t*)0x200005b8 = 4;
> >         *(uint8_t*)0x200005b9 = 0;
> >         *(uint8_t*)0x200005ba = 0x10;
> >         *(uint32_t*)0x200005bc = 0;
> >         *(uint32_t*)0x200005c0 = 0;
> >         *(uint32_t*)0x200005c4 = 0;
> >         *(uint32_t*)0x200005c8 = htobe32(0xe0000002);
> >         *(uint32_t*)0x200005d8 = htobe32(0);
> >         *(uint8_t*)0x200005dc = 0x33;
> >         *(uint16_t*)0x200005e0 = 0xa;
> >         *(uint8_t*)0x200005e4 = 0xfc;
> >         *(uint8_t*)0x200005e5 = 0;
> >         memset((void*)0x200005e6, 0, 13);
> >         *(uint8_t*)0x200005f3 = 0;
> >         *(uint32_t*)0x200005f4 = 0;
> >         *(uint8_t*)0x200005f8 = 1;
> >         *(uint8_t*)0x200005f9 = 0;
> >         *(uint8_t*)0x200005fa = 0x20;
> >         *(uint32_t*)0x200005fc = 0;
> >         *(uint32_t*)0x20000600 = 0;
> >         *(uint32_t*)0x20000604 = 0;
> >         *(uint8_t*)0x20000608 = 0xac;
> >         *(uint8_t*)0x20000609 = 0x14;
> >         *(uint8_t*)0x2000060a = 0x14;
> >         *(uint8_t*)0x2000060b = 0xfa;
> >         *(uint32_t*)0x20000618 = htobe32(0);
> >         *(uint8_t*)0x2000061c = 0x2b;
> >         *(uint16_t*)0x20000620 = 0xa;
> >         *(uint8_t*)0x20000624 = 0xac;
> >         *(uint8_t*)0x20000625 = 0x14;
> >         *(uint8_t*)0x20000626 = 0x14;
> >         *(uint8_t*)0x20000627 = 0xbb;
> >         *(uint32_t*)0x20000634 = 0;
> >         *(uint8_t*)0x20000638 = 0;
> >         *(uint8_t*)0x20000639 = 0;
> >         *(uint8_t*)0x2000063a = 3;
> >         *(uint32_t*)0x2000063c = 0;
> >         *(uint32_t*)0x20000640 = 0;
> >         *(uint32_t*)0x20000644 = 0;
> >         memcpy((void*)0x20000648,
> >                         " \001\000\000\000\000\000\000\000\000\000\000\000\000\000\001", 16);
> >         *(uint32_t*)0x20000658 = htobe32(0);
> >         *(uint8_t*)0x2000065c = 0x33;
> >         *(uint16_t*)0x20000660 = 0xa;
> >         *(uint32_t*)0x20000664 = htobe32(0);
> >         *(uint32_t*)0x20000674 = 0;
> >         *(uint8_t*)0x20000678 = 3;
> >         *(uint8_t*)0x20000679 = 0;
> >         *(uint8_t*)0x2000067a = 0;
> >         *(uint32_t*)0x2000067c = 0;
> >         *(uint32_t*)0x20000680 = 0;
> >         *(uint32_t*)0x20000684 = 0;
> >         *(uint32_t*)0x20000688 = htobe32(0x7f000001);
> >         *(uint32_t*)0x20000698 = htobe32(0);
> >         *(uint8_t*)0x2000069c = 0x6c;
> >         *(uint16_t*)0x200006a0 = 0xa;
> >         *(uint8_t*)0x200006a4 = -1;
> >         *(uint8_t*)0x200006a5 = 1;
> >         memset((void*)0x200006a6, 0, 13);
> >         *(uint8_t*)0x200006b3 = 1;
> >         *(uint32_t*)0x200006b4 = 0;
> >         *(uint8_t*)0x200006b8 = 0;
> >         *(uint8_t*)0x200006b9 = 0;
> >         *(uint8_t*)0x200006ba = 0;
> >         *(uint32_t*)0x200006bc = 0;
> >         *(uint32_t*)0x200006c0 = 0;
> >         *(uint32_t*)0x200006c4 = -1;
> >         *(uint64_t*)0x20000208 = 0x208;
> >         *(uint64_t*)0x20000498 = 1;
> >         *(uint64_t*)0x200004a0 = 0;
> >         *(uint64_t*)0x200004a8 = 0;
> >         *(uint32_t*)0x200004b0 = 0;
> >         ret = syscall(__NR_sendmsg, r[1], 0x20000480ul, 0ul);
> >         printf("sendmsg() 2 : %d\n", ret);
> >         return 0;
> > }
> > ```