From 9b0a8da8c4c6e91012ab03a801acc5d8011c7c2f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 18 Jun 2018 05:24:31 -0700 Subject: net/ipv6: respect rcu grace period before freeing fib6_info syzbot reported use after free that is caused by fib6_info being freed without a proper RCU grace period. CPU: 0 PID: 1407 Comm: udevd Not tainted 4.17.0+ #39 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 __read_once_size include/linux/compiler.h:188 [inline] find_rr_leaf net/ipv6/route.c:705 [inline] rt6_select net/ipv6/route.c:761 [inline] fib6_table_lookup+0x12b7/0x14d0 net/ipv6/route.c:1823 ip6_pol_route+0x1c2/0x1020 net/ipv6/route.c:1856 ip6_pol_route_output+0x54/0x70 net/ipv6/route.c:2082 fib6_rule_lookup+0x211/0x6d0 net/ipv6/fib6_rules.c:122 ip6_route_output_flags+0x2c5/0x350 net/ipv6/route.c:2110 ip6_route_output include/net/ip6_route.h:82 [inline] icmpv6_xrlim_allow net/ipv6/icmp.c:211 [inline] icmp6_send+0x147c/0x2da0 net/ipv6/icmp.c:535 icmpv6_send+0x17a/0x300 net/ipv6/ip6_icmp.c:43 ip6_link_failure+0xa5/0x790 net/ipv6/route.c:2244 dst_link_failure include/net/dst.h:427 [inline] ndisc_error_report+0xd1/0x1c0 net/ipv6/ndisc.c:695 neigh_invalidate+0x246/0x550 net/core/neighbour.c:892 neigh_timer_handler+0xaf9/0xde0 net/core/neighbour.c:978 call_timer_fn+0x230/0x940 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers+0x79e/0xc50 kernel/time/timer.c:1666 run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1d1/0x200 kernel/softirq.c:404 exiting_irq arch/x86/include/asm/apic.h:527 [inline] smp_apic_timer_interrupt+0x17e/0x710 arch/x86/kernel/apic/apic.c:1052 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 RIP: 0010:strlen+0x5e/0xa0 lib/string.c:482 Code: 24 00 74 3b 48 bb 00 00 00 00 00 fc ff df 4c 89 e0 48 83 c0 01 48 89 c2 48 89 c1 48 c1 ea 03 83 e1 07 0f b6 14 1a 38 ca 7f 04 <84> d2 75 23 80 38 00 75 de 48 83 c4 08 4c 29 e0 5b 41 5c 5d c3 48 RSP: 0018:ffff8801af117850 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff880197f53bd0 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff81c5b06c RDI: ffff880197f53bc0 RBP: ffff8801af117868 R08: ffff88019a976540 R09: 0000000000000000 R10: ffff88019a976540 R11: 0000000000000000 R12: ffff880197f53bc0 R13: ffff880197f53bc0 R14: ffffffff899e4e90 R15: ffff8801d91c6a00 strlen include/linux/string.h:267 [inline] getname_kernel+0x24/0x370 fs/namei.c:218 open_exec+0x17/0x70 fs/exec.c:882 load_elf_binary+0x968/0x5610 fs/binfmt_elf.c:780 search_binary_handler+0x17d/0x570 fs/exec.c:1653 exec_binprm fs/exec.c:1695 [inline] __do_execve_file.isra.35+0x16fe/0x2710 fs/exec.c:1819 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1959 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f1576a46207 Code: 77 19 f4 48 89 d7 44 89 c0 0f 05 48 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 f7 d8 64 41 89 01 eb df b8 3b 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 02 f3 c3 48 8b 15 00 8c 2d 00 f7 d8 64 89 02 RSP: 002b:00007ffff2784568 EFLAGS: 00000202 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f1576a46207 RDX: 0000000001215b10 RSI: 00007ffff2784660 RDI: 00007ffff2785670 RBP: 0000000000625500 R08: 000000000000589c R09: 000000000000589c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000001215b10 R13: 0000000000000007 R14: 0000000001204250 R15: 0000000000000005 Allocated by task 12188: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] kzalloc include/linux/slab.h:706 [inline] fib6_info_alloc+0xbb/0x280 net/ipv6/ip6_fib.c:152 ip6_route_info_create+0x782/0x2b50 net/ipv6/route.c:3013 ip6_route_add+0x23/0xb0 net/ipv6/route.c:3154 ipv6_route_ioctl+0x5a5/0x760 net/ipv6/route.c:3660 inet6_ioctl+0x100/0x1f0 net/ipv6/af_inet6.c:546 sock_do_ioctl+0xe4/0x3e0 net/socket.c:973 sock_ioctl+0x30d/0x680 net/socket.c:1097 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16f0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 1402: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 fib6_info_destroy+0x29b/0x350 net/ipv6/ip6_fib.c:207 fib6_info_release include/net/ip6_fib.h:286 [inline] __ip6_del_rt_siblings net/ipv6/route.c:3235 [inline] ip6_route_del+0x11c4/0x13b0 net/ipv6/route.c:3316 ipv6_route_ioctl+0x616/0x760 net/ipv6/route.c:3663 inet6_ioctl+0x100/0x1f0 net/ipv6/af_inet6.c:546 sock_do_ioctl+0xe4/0x3e0 net/socket.c:973 sock_ioctl+0x30d/0x680 net/socket.c:1097 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1cf/0x16f0 fs/ioctl.c:684 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701 __do_sys_ioctl fs/ioctl.c:708 [inline] __se_sys_ioctl fs/ioctl.c:706 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801b5df2580 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 8 bytes inside of 256-byte region [ffff8801b5df2580, ffff8801b5df2680) The buggy address belongs to the page: page:ffffea0006d77c80 count:1 mapcount:0 mapping:ffff8801da8007c0 index:0xffff8801b5df2e40 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006c5cc48 ffffea0007363308 ffff8801da8007c0 raw: ffff8801b5df2e40 ffff8801b5df2080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b5df2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b5df2500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801b5df2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b5df2600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b5df2680: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb Fixes: a64efe142f5e ("net/ipv6: introduce fib6_info struct and helpers") Signed-off-by: Eric Dumazet Cc: David Ahern Reported-by: syzbot+9e6d75e3edef427ee888@syzkaller.appspotmail.com Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/ip6_fib.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 39d1d487eca2..1fb2f3118d60 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -167,8 +167,9 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags) return f6i; } -void fib6_info_destroy(struct fib6_info *f6i) +void fib6_info_destroy_rcu(struct rcu_head *head) { + struct fib6_info *f6i = container_of(head, struct fib6_info, rcu); struct rt6_exception_bucket *bucket; struct dst_metrics *m; @@ -206,7 +207,7 @@ void fib6_info_destroy(struct fib6_info *f6i) kfree(f6i); } -EXPORT_SYMBOL_GPL(fib6_info_destroy); +EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu); static struct fib6_node *node_alloc(struct net *net) { -- cgit v1.2.3