Check that allocator does not introduce lots of unnecessary synchronization #207
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dvyukov
referenced
this issue
in google/ktsan
Sep 22, 2015
xairy
referenced
this issue
in google/ktsan
Jan 31, 2019
kmsan was able to trigger a kernel-infoleak using a gre device [1] nlmsg_populate_fdb_fill() has a hard coded assumption that dev->addr_len is ETH_ALEN, as normally guaranteed for ARPHRD_ETHER devices. A similar issue was fixed recently in commit da71577 ("rtnetlink: Disallow FDB configuration for non-Ethernet device") [1] BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:143 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4c0/0x2700 lib/iov_iter.c:576 CPU: 0 PID: 6697 Comm: syz-executor310 Not tainted 4.20.0-rc3+ #95 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+0x32d/0x480 lib/dump_stack.c:113 kmsan_report+0x12c/0x290 mm/kmsan/kmsan.c:683 kmsan_internal_check_memory+0x32a/0xa50 mm/kmsan/kmsan.c:743 kmsan_copy_to_user+0x78/0xd0 mm/kmsan/kmsan_hooks.c:634 copyout lib/iov_iter.c:143 [inline] _copy_to_iter+0x4c0/0x2700 lib/iov_iter.c:576 copy_to_iter include/linux/uio.h:143 [inline] skb_copy_datagram_iter+0x4e2/0x1070 net/core/datagram.c:431 skb_copy_datagram_msg include/linux/skbuff.h:3316 [inline] netlink_recvmsg+0x6f9/0x19d0 net/netlink/af_netlink.c:1975 sock_recvmsg_nosec net/socket.c:794 [inline] sock_recvmsg+0x1d1/0x230 net/socket.c:801 ___sys_recvmsg+0x444/0xae0 net/socket.c:2278 __sys_recvmsg net/socket.c:2327 [inline] __do_sys_recvmsg net/socket.c:2337 [inline] __se_sys_recvmsg+0x2fa/0x450 net/socket.c:2334 __x64_sys_recvmsg+0x4a/0x70 net/socket.c:2334 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x441119 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 db 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffc7f008a8 EFLAGS: 00000207 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000441119 RDX: 0000000000000040 RSI: 00000000200005c0 RDI: 0000000000000003 RBP: 00000000006cc018 R08: 0000000000000100 R09: 0000000000000100 R10: 0000000000000100 R11: 0000000000000207 R12: 0000000000402080 R13: 0000000000402110 R14: 0000000000000000 R15: 0000000000000000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:246 [inline] kmsan_save_stack mm/kmsan/kmsan.c:261 [inline] kmsan_internal_chain_origin+0x13d/0x240 mm/kmsan/kmsan.c:469 kmsan_memcpy_memmove_metadata+0x1a9/0xf70 mm/kmsan/kmsan.c:344 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:362 __msan_memcpy+0x61/0x70 mm/kmsan/kmsan_instr.c:162 __nla_put lib/nlattr.c:744 [inline] nla_put+0x20a/0x2d0 lib/nlattr.c:802 nlmsg_populate_fdb_fill+0x444/0x810 net/core/rtnetlink.c:3466 nlmsg_populate_fdb net/core/rtnetlink.c:3775 [inline] ndo_dflt_fdb_dump+0x73a/0x960 net/core/rtnetlink.c:3807 rtnl_fdb_dump+0x1318/0x1cb0 net/core/rtnetlink.c:3979 netlink_dump+0xc79/0x1c90 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x10c4/0x11d0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [inline] rtnetlink_rcv_msg+0x141b/0x1540 net/core/rtnetlink.c:4910 netlink_rcv_skb+0x394/0x640 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4965 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x1699/0x1740 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x13c7/0x1440 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116 __sys_sendmsg net/socket.c:2154 [inline] __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg+0x305/0x460 net/socket.c:2161 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:246 [inline] kmsan_internal_poison_shadow+0x6d/0x130 mm/kmsan/kmsan.c:170 kmsan_kmalloc+0xa1/0x100 mm/kmsan/kmsan_hooks.c:186 __kmalloc+0x14c/0x4d0 mm/slub.c:3825 kmalloc include/linux/slab.h:551 [inline] __hw_addr_create_ex net/core/dev_addr_lists.c:34 [inline] __hw_addr_add_ex net/core/dev_addr_lists.c:80 [inline] __dev_mc_add+0x357/0x8a0 net/core/dev_addr_lists.c:670 dev_mc_add+0x6d/0x80 net/core/dev_addr_lists.c:687 ip_mc_filter_add net/ipv4/igmp.c:1128 [inline] igmp_group_added+0x4d4/0xb80 net/ipv4/igmp.c:1311 __ip_mc_inc_group+0xea9/0xf70 net/ipv4/igmp.c:1444 ip_mc_inc_group net/ipv4/igmp.c:1453 [inline] ip_mc_up+0x1c3/0x400 net/ipv4/igmp.c:1775 inetdev_event+0x1d03/0x1d80 net/ipv4/devinet.c:1522 notifier_call_chain kernel/notifier.c:93 [inline] __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x13d/0x240 kernel/notifier.c:401 __dev_notify_flags+0x3da/0x860 net/core/dev.c:1733 dev_change_flags+0x1ac/0x230 net/core/dev.c:7569 do_setlink+0x165f/0x5ea0 net/core/rtnetlink.c:2492 rtnl_newlink+0x2ad7/0x35a0 net/core/rtnetlink.c:3111 rtnetlink_rcv_msg+0x1148/0x1540 net/core/rtnetlink.c:4947 netlink_rcv_skb+0x394/0x640 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4965 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x1699/0x1740 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x13c7/0x1440 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116 __sys_sendmsg net/socket.c:2154 [inline] __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg+0x305/0x460 net/socket.c:2161 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Bytes 36-37 of 105 are uninitialized Memory access of size 105 starts at ffff88819686c000 Data copied to user address 0000000020000380 Fixes: d83b060 ("net: add fdb generic dump routine") Signed-off-by: Eric Dumazet <[email protected]> Cc: John Fastabend <[email protected]> Cc: Ido Schimmel <[email protected]> Cc: David Ahern <[email protected]> Reviewed-by: Ido Schimmel <[email protected]> Signed-off-by: David S. Miller <[email protected]>
xairy
referenced
this issue
in google/ktsan
Jan 31, 2019
syzbot reported a kernel-infoleak, which is caused by an uninitialized
field(sin6_flowinfo) of addr->a.v6 in sctp_inet6addr_event().
The call trace is as below:
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x19a/0x230 lib/usercopy.c:33
CPU: 1 PID: 8164 Comm: syz-executor2 Not tainted 4.20.0-rc3+ #95
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+0x32d/0x480 lib/dump_stack.c:113
kmsan_report+0x12c/0x290 mm/kmsan/kmsan.c:683
kmsan_internal_check_memory+0x32a/0xa50 mm/kmsan/kmsan.c:743
kmsan_copy_to_user+0x78/0xd0 mm/kmsan/kmsan_hooks.c:634
_copy_to_user+0x19a/0x230 lib/usercopy.c:33
copy_to_user include/linux/uaccess.h:183 [inline]
sctp_getsockopt_local_addrs net/sctp/socket.c:5998 [inline]
sctp_getsockopt+0x15248/0x186f0 net/sctp/socket.c:7477
sock_common_getsockopt+0x13f/0x180 net/core/sock.c:2937
__sys_getsockopt+0x489/0x550 net/socket.c:1939
__do_sys_getsockopt net/socket.c:1950 [inline]
__se_sys_getsockopt+0xe1/0x100 net/socket.c:1947
__x64_sys_getsockopt+0x62/0x80 net/socket.c:1947
do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
sin6_flowinfo is not really used by SCTP, so it will be fixed by simply
setting it to 0.
The issue exists since very beginning.
Thanks Alexander for the reproducer provided.
Reported-by: [email protected]
Signed-off-by: Xin Long <[email protected]>
Acked-by: Marcelo Ricardo Leitner <[email protected]>
Acked-by: Neil Horman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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We need to double check that memory allocator (slab, slub) does not introduce lots of unnecessary synchronization. We need to ignore all synchronization in the allocator. Otherwise even fast-path will synchronize threads on per-cpu cache. Slow path will synchronize even threads running on different cpus. We should ignore that synchronization as much as possible.
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