kernel/linux.git/net/ipv6/ip6_fib.c, branch linux-6.9.y

ipv6: fix possible race in __fib6_drop_pcpu_from()

2024-06-21T12:40:10+00:00

[ Upstream commit b01e1c030770ff3b4fe37fc7cc6bca03f594133f ] syzbot found a race in __fib6_drop_pcpu_from() [1] If compiler reads more than once (*ppcpu_rt), second read could read NULL, if another cpu clears the value in rt6_get_pcpu_route(). Add a READ_ONCE() to prevent this race. Also add rcu_read_lock()/rcu_read_unlock() because we rely on RCU protection while dereferencing pcpu_rt. [1] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097] CPU: 0 PID: 7543 Comm: kworker/u8:17 Not tainted 6.10.0-rc1-syzkaller-00013-g2bfcfd584ff5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Workqueue: netns cleanup_net RIP: 0010:__fib6_drop_pcpu_from.part.0+0x10a/0x370 net/ipv6/ip6_fib.c:984 Code: f8 48 c1 e8 03 80 3c 28 00 0f 85 16 02 00 00 4d 8b 3f 4d 85 ff 74 31 e8 74 a7 fa f7 49 8d bf 90 00 00 00 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 1e 02 00 00 49 8b 87 90 00 00 00 48 8b 0c 24 48 RSP: 0018:ffffc900040df070 EFLAGS: 00010206 RAX: 0000000000000012 RBX: 0000000000000001 RCX: ffffffff89932e16 RDX: ffff888049dd1e00 RSI: ffffffff89932d7c RDI: 0000000000000091 RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000007 R10: 0000000000000001 R11: 0000000000000006 R12: ffff88807fa080b8 R13: fffffbfff1a9a07d R14: ffffed100ff41022 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32c26000 CR3: 000000005d56e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __fib6_drop_pcpu_from net/ipv6/ip6_fib.c:966 [inline] fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1027 [inline] fib6_purge_rt+0x7f2/0x9f0 net/ipv6/ip6_fib.c:1038 fib6_del_route net/ipv6/ip6_fib.c:1998 [inline] fib6_del+0xa70/0x17b0 net/ipv6/ip6_fib.c:2043 fib6_clean_node+0x426/0x5b0 net/ipv6/ip6_fib.c:2205 fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2127 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2175 fib6_clean_tree+0xd7/0x120 net/ipv6/ip6_fib.c:2255 __fib6_clean_all+0x100/0x2d0 net/ipv6/ip6_fib.c:2271 rt6_sync_down_dev net/ipv6/route.c:4906 [inline] rt6_disable_ip+0x7ed/0xa00 net/ipv6/route.c:4911 addrconf_ifdown.isra.0+0x117/0x1b40 net/ipv6/addrconf.c:3855 addrconf_notify+0x223/0x19e0 net/ipv6/addrconf.c:3778 notifier_call_chain+0xb9/0x410 kernel/notifier.c:93 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1992 call_netdevice_notifiers_extack net/core/dev.c:2030 [inline] call_netdevice_notifiers net/core/dev.c:2044 [inline] dev_close_many+0x333/0x6a0 net/core/dev.c:1585 unregister_netdevice_many_notify+0x46d/0x19f0 net/core/dev.c:11193 unregister_netdevice_many net/core/dev.c:11276 [inline] default_device_exit_batch+0x85b/0xae0 net/core/dev.c:11759 ops_exit_list+0x128/0x180 net/core/net_namespace.c:178 cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:640 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Fixes: d52d3997f843 ("ipv6: Create percpu rt6_info") Signed-off-by: Eric Dumazet Cc: Martin KaFai Lau Link: https://lore.kernel.org/r/20240604193549.981839-1-edumazet@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

ipv6: fib: hide unused 'pn' variable

2024-04-09T13:49:19+00:00

When CONFIG_IPV6_SUBTREES is disabled, the only user is hidden, causing a 'make W=1' warning: net/ipv6/ip6_fib.c: In function 'fib6_add': net/ipv6/ip6_fib.c:1388:32: error: variable 'pn' set but not used [-Werror=unused-but-set-variable] Add another #ifdef around the variable declaration, matching the other uses in this file. Fixes: 66729e18df08 ("[IPV6] ROUTE: Make sure we have fn->leaf when adding a node on subtree.") Link: https://lore.kernel.org/netdev/20240322131746.904943-1-arnd@kernel.org/ Reviewed-by: David Ahern Signed-off-by: Arnd Bergmann Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240408074219.3030256-1-arnd@kernel.org Signed-off-by: Paolo Abeni

ipv6: Fix infinite recursion in fib6_dump_done().

2024-04-03T02:10:57+00:00

syzkaller reported infinite recursive calls of fib6_dump_done() during netlink socket destruction. [1] From the log, syzkaller sent an AF_UNSPEC RTM_GETROUTE message, and then the response was generated. The following recvmmsg() resumed the dump for IPv6, but the first call of inet6_dump_fib() failed at kzalloc() due to the fault injection. [0] 12:01:34 executing program 3: r0 = socket$nl_route(0x10, 0x3, 0x0) sendmsg$nl_route(r0, ... snip ...) recvmmsg(r0, ... snip ...) (fail_nth: 8) Here, fib6_dump_done() was set to nlk_sk(sk)->cb.done, and the next call of inet6_dump_fib() set it to nlk_sk(sk)->cb.args[3]. syzkaller stopped receiving the response halfway through, and finally netlink_sock_destruct() called nlk_sk(sk)->cb.done(). fib6_dump_done() calls fib6_dump_end() and nlk_sk(sk)->cb.done() if it is still not NULL. fib6_dump_end() rewrites nlk_sk(sk)->cb.done() by nlk_sk(sk)->cb.args[3], but it has the same function, not NULL, calling itself recursively and hitting the stack guard page. To avoid the issue, let's set the destructor after kzalloc(). [0]: FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 432110 Comm: syz-executor.3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:117) should_fail_ex (lib/fault-inject.c:52 lib/fault-inject.c:153) should_failslab (mm/slub.c:3733) kmalloc_trace (mm/slub.c:3748 mm/slub.c:3827 mm/slub.c:3992) inet6_dump_fib (./include/linux/slab.h:628 ./include/linux/slab.h:749 net/ipv6/ip6_fib.c:662) rtnl_dump_all (net/core/rtnetlink.c:4029) netlink_dump (net/netlink/af_netlink.c:2269) netlink_recvmsg (net/netlink/af_netlink.c:1988) ____sys_recvmsg (net/socket.c:1046 net/socket.c:2801) ___sys_recvmsg (net/socket.c:2846) do_recvmmsg (net/socket.c:2943) __x64_sys_recvmmsg (net/socket.c:3041 net/socket.c:3034 net/socket.c:3034) [1]: BUG: TASK stack guard page was hit at 00000000f2fa9af1 (stack is 00000000b7912430..000000009a436beb) stack guard page: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 223719 Comm: kworker/1:3 Not tainted 6.8.0-12821-g537c2e91d354-dirty #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: events netlink_sock_destruct_work RIP: 0010:fib6_dump_done (net/ipv6/ip6_fib.c:570) Code: 3c 24 e8 f3 e9 51 fd e9 28 fd ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 41 57 41 56 41 55 41 54 55 48 89 fd <53> 48 8d 5d 60 e8 b6 4d 07 fd 48 89 da 48 b8 00 00 00 00 00 fc ff RSP: 0018:ffffc9000d980000 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffffff84405990 RCX: ffffffff844059d3 RDX: ffff8881028e0000 RSI: ffffffff84405ac2 RDI: ffff88810c02f358 RBP: ffff88810c02f358 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000224 R12: 0000000000000000 R13: ffff888007c82c78 R14: ffff888007c82c68 R15: ffff888007c82c68 FS: 0000000000000000(0000) GS:ffff88811b100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc9000d97fff8 CR3: 0000000102309002 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <#DF> fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1)) fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1)) ... fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1)) fib6_dump_done (net/ipv6/ip6_fib.c:572 (discriminator 1)) netlink_sock_destruct (net/netlink/af_netlink.c:401) __sk_destruct (net/core/sock.c:2177 (discriminator 2)) sk_destruct (net/core/sock.c:2224) __sk_free (net/core/sock.c:2235) sk_free (net/core/sock.c:2246) process_one_work (kernel/workqueue.c:3259) worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) kthread (kernel/kthread.c:388) ret_from_fork (arch/x86/kernel/process.c:153) ret_from_fork_asm (arch/x86/entry/entry_64.S:256) Modules linked in: Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzkaller Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240401211003.25274-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski

inet: allow ip_valid_fib_dump_req() to be called with RTNL or RCU

2024-02-26T11:46:12+00:00

Add a new field into struct fib_dump_filter, to let callers tell if they use RTNL locking or RCU. This is used in the following patch, when inet_dump_fib() no longer holds RTNL. Signed-off-by: Eric Dumazet Reviewed-by: Donald Hunter Signed-off-by: David S. Miller

ipv6: Simplify the allocation of slab caches

2024-02-21T11:28:58+00:00

Use the new KMEM_CACHE() macro instead of direct kmem_cache_create to simplify the creation of SLAB caches. Signed-off-by: Kunwu Chan Reviewed-by: Michal Swiatkowski Signed-off-by: David S. Miller

net/ipv6: Remove expired routes with a separated list of routes.

2024-02-12T10:24:12+00:00

FIB6 GC walks trees of fib6_tables to remove expired routes. Walking a tree can be expensive if the number of routes in a table is big, even if most of them are permanent. Checking routes in a separated list of routes having expiration will avoid this potential issue. Reviewed-by: David Ahern Signed-off-by: Kui-Feng Lee Signed-off-by: David S. Miller

net/ipv6: resolve warning in ip6_fib.c

2024-01-24T01:22:23+00:00

In some configurations, the 'iter' variable in function fib6_repair_tree() is unused, resulting the following warning when compiled with W=1. net/ipv6/ip6_fib.c:1781:6: warning: variable 'iter' set but not used [-Wunused-but-set-variable] 1781 | int iter = 0; | ^ It is unclear what is the advantage of this RT6_TRACE() macro[1], since users can control pr_debug() in runtime, which is better than at compilation time. pr_debug() has no overhead when disabled. Remove the RT6_TRACE() in favor of simple pr_debug() helpers. [1] Link: https://lore.kernel.org/all/ZZwSEJv2HgI0cD4J@gmail.com/ Signed-off-by: Breno Leitao Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240122181955.2391676-2-leitao@debian.org Signed-off-by: Jakub Kicinski

net/ipv6: Remove unnecessary pr_debug() logs

2024-01-24T01:22:23+00:00

In the ipv6 system, we have some logs basically dumping the name of the function that is being called. This is not ideal, since ftrace give us "for free". Moreover, checkpatch is not happy when touching that code: WARNING: Unnecessary ftrace-like logging - prefer using ftrace Remove debug functions that only print the current function name. Signed-off-by: Breno Leitao Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240122181955.2391676-1-leitao@debian.org Signed-off-by: Jakub Kicinski

net/ipv6: Revert remove expired routes with a separated list of routes

2023-12-21T08:01:30+00:00

This reverts commit 3dec89b14d37ee635e772636dad3f09f78f1ab87. The commit has some race conditions given how expires is managed on a fib6_info in relation to gc start, adding the entry to the gc list and setting the timer value leading to UAF. Revert the commit and try again in a later release. Fixes: 3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes") Cc: Kui-Feng Lee Signed-off-by: David Ahern Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20231219030243.25687-1-dsahern@kernel.org Signed-off-by: Paolo Abeni

ipv6: fix potential NULL deref in fib6_add()

2023-12-01T07:20:14+00:00

If fib6_find_prefix() returns NULL, we should silently fallback using fib6_null_entry regardless of RT6_DEBUG value. syzbot reported: WARNING: CPU: 0 PID: 5477 at net/ipv6/ip6_fib.c:1516 fib6_add+0x310d/0x3fa0 net/ipv6/ip6_fib.c:1516 Modules linked in: CPU: 0 PID: 5477 Comm: syz-executor.0 Not tainted 6.7.0-rc2-syzkaller-00029-g9b6de136b5f0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:fib6_add+0x310d/0x3fa0 net/ipv6/ip6_fib.c:1516 Code: 00 48 8b 54 24 68 e8 42 22 00 00 48 85 c0 74 14 49 89 c6 e8 d5 d3 c2 f7 eb 5d e8 ce d3 c2 f7 e9 ca 00 00 00 e8 c4 d3 c2 f7 90 <0f> 0b 90 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 38 80 3c 01 00 RSP: 0018:ffffc90005067740 EFLAGS: 00010293 RAX: ffffffff89cba5bc RBX: ffffc90005067ab0 RCX: ffff88801a2e9dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90005067980 R08: ffffffff89cbca85 R09: 1ffff110040d4b85 R10: dffffc0000000000 R11: ffffed10040d4b86 R12: 00000000ffffffff R13: 1ffff110051c3904 R14: ffff8880206a5c00 R15: ffff888028e1c820 FS: 00007f763783c6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f763783bff8 CR3: 000000007f74d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __ip6_ins_rt net/ipv6/route.c:1303 [inline] ip6_route_add+0x88/0x120 net/ipv6/route.c:3847 ipv6_route_ioctl+0x525/0x7b0 net/ipv6/route.c:4467 inet6_ioctl+0x21a/0x270 net/ipv6/af_inet6.c:575 sock_do_ioctl+0x152/0x460 net/socket.c:1220 sock_ioctl+0x615/0x8c0 net/socket.c:1339 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82 Fixes: 7bbfe00e0252 ("ipv6: fix general protection fault in fib6_add()") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Wei Wang Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20231129160630.3509216-1-edumazet@google.com Signed-off-by: Jakub Kicinski