• Hannes Frederic Sowa's avatar
    net: add validation for the socket syscall protocol argument · 79462ad0
    Hannes Frederic Sowa authored
    郭永刚 reported that one could simply crash the kernel as root by
    using a simple program:
    
    	int socket_fd;
    	struct sockaddr_in addr;
    	addr.sin_port = 0;
    	addr.sin_addr.s_addr = INADDR_ANY;
    	addr.sin_family = 10;
    
    	socket_fd = socket(10,3,0x40000000);
    	connect(socket_fd , &addr,16);
    
    AF_INET, AF_INET6 sockets actually only support 8-bit protocol
    identifiers. inet_sock's skc_protocol field thus is sized accordingly,
    thus larger protocol identifiers simply cut off the higher bits and
    store a zero in the protocol fields.
    
    This could lead to e.g. NULL function pointer because as a result of
    the cut off inet_num is zero and we call down to inet_autobind, which
    is NULL for raw sockets.
    
    kernel: Call Trace:
    kernel:  [<ffffffff816db90e>] ? inet_autobind+0x2e/0x70
    kernel:  [<ffffffff816db9a4>] inet_dgram_connect+0x54/0x80
    kernel:  [<ffffffff81645069>] SYSC_connect+0xd9/0x110
    kernel:  [<ffffffff810ac51b>] ? ptrace_notify+0x5b/0x80
    kernel:  [<ffffffff810236d8>] ? syscall_trace_enter_phase2+0x108/0x200
    kernel:  [<ffffffff81645e0e>] SyS_connect+0xe/0x10
    kernel:  [<ffffffff81779515>] tracesys_phase2+0x84/0x89
    
    I found no particular commit which introduced this problem.
    
    CVE: CVE-2015-8543
    Cc: Cong Wang <cwang@twopensource.com>
    Reported-by: default avatar郭永刚 <guoyonggang@360.cn>
    Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    79462ad0
af_ax25.c 43.9 KB