• Xin Long's avatar
    xfrm: add the missing verify_sec_ctx_len check in xfrm_add_acquire · a1a7e3a3
    Xin Long authored
    Without doing verify_sec_ctx_len() check in xfrm_add_acquire(), it may be
    out-of-bounds to access uctx->ctx_str with uctx->ctx_len, as noticed by
    syz:
    
      BUG: KASAN: slab-out-of-bounds in selinux_xfrm_alloc_user+0x237/0x430
      Read of size 768 at addr ffff8880123be9b4 by task syz-executor.1/11650
    
      Call Trace:
       dump_stack+0xe8/0x16e
       print_address_description.cold.3+0x9/0x23b
       kasan_report.cold.4+0x64/0x95
       memcpy+0x1f/0x50
       selinux_xfrm_alloc_user+0x237/0x430
       security_xfrm_policy_alloc+0x5c/0xb0
       xfrm_policy_construct+0x2b1/0x650
       xfrm_add_acquire+0x21d/0xa10
       xfrm_user_rcv_msg+0x431/0x6f0
       netlink_rcv_skb+0x15a/0x410
       xfrm_netlink_rcv+0x6d/0x90
       netlink_unicast+0x50e/0x6a0
       netlink_sendmsg+0x8ae/0xd40
       sock_sendmsg+0x133/0x170
       ___sys_sendmsg+0x834/0x9a0
       __sys_sendmsg+0x100/0x1e0
       do_syscall_64+0xe5/0x660
       entry_SYSCALL_64_after_hwframe+0x6a/0xdf
    
    So fix it by adding the missing verify_sec_ctx_len check there.
    
    Fixes: 980ebd25 ("[IPSEC]: Sync series - acquire insert")
    Reported-by: default avatarHangbin Liu <liuhangbin@gmail.com>
    Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
    Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
    a1a7e3a3
xfrm_user.c 78.3 KB