KASAN: slab-out-of-bounds Read in selinux_xfrm_alloc

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	KASAN: slab-out-of-bounds Read in selinux_xfrm_alloc_user	17	C		done	3	2097d	2102d	1/1	fixed on 2020/04/16 05:11
upstream	KASAN: slab-out-of-bounds Read in selinux_xfrm_alloc_user selinux	17	C	done		1	2084d	2082d	15/29	fixed on 2020/05/10 10:42

random: sshd: uninitialized urandom read (32 bytes read) audit: type=1400 audit(1584907391.239:36): avc: denied { map } for pid=7333 comm="syz-executor381" path="/root/syz-executor381074400" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline] BUG: KASAN: slab-out-of-bounds in selinux_xfrm_alloc_user+0x1e3/0x3b0 security/selinux/xfrm.c:102 Read of size 768 at addr ffff888086059374 by task syz-executor381/7333 CPU: 0 PID: 7333 Comm: syz-executor381 Not tainted 4.14.174-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:347 [inline] selinux_xfrm_alloc_user+0x1e3/0x3b0 security/selinux/xfrm.c:102 security_xfrm_policy_alloc+0x76/0xb0 security/security.c:1574 copy_from_user_sec_ctx net/xfrm/xfrm_user.c:1418 [inline] xfrm_policy_construct+0x287/0x570 net/xfrm/xfrm_user.c:1583 xfrm_add_acquire+0x1f5/0x990 net/xfrm/xfrm_user.c:2218 xfrm_user_rcv_msg+0x37d/0x5f0 net/xfrm/xfrm_user.c:2613 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433 xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2621 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xc5/0x100 net/socket.c:656 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4405f9 RSP: 002b:00007fff85641518 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004405f9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401e80 R13: 0000000000401f10 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 7333: save_stack+0x32/0xa0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.0+0x35/0xd0 net/core/skbuff.c:137 __alloc_skb+0xca/0x4c0 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:980 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1159 [inline] netlink_sendmsg+0x7de/0xbe0 net/netlink/af_netlink.c:1853 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xc5/0x100 net/socket.c:656 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff888086059240 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 308 bytes inside of 1024-byte region [ffff888086059240, ffff888086059640) The buggy address belongs to the page: page:ffffea0002181600 count:1 mapcount:0 mapping:ffff888086058040 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff888086058040 0000000000000000 0000000100000007 raw: ffffea00029880a0 ffffea00025512a0 ffff88812fe56ac0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888086059500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888086059580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888086059600: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ^ ffff888086059680: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff888086059700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================