• Alexei Starovoitov's avatar
    bpf: add unprivileged bpf tests · bf508877
    Alexei Starovoitov authored
    Add new tests samples/bpf/test_verifier:
    
    unpriv: return pointer
      checks that pointer cannot be returned from the eBPF program
    
    unpriv: add const to pointer
    unpriv: add pointer to pointer
    unpriv: neg pointer
      checks that pointer arithmetic is disallowed
    
    unpriv: cmp pointer with const
    unpriv: cmp pointer with pointer
      checks that comparison of pointers is disallowed
      Only one case allowed 'void *value = bpf_map_lookup_elem(..); if (value == 0) ...'
    
    unpriv: check that printk is disallowed
      since bpf_trace_printk is not available to unprivileged
    
    unpriv: pass pointer to helper function
      checks that pointers cannot be passed to functions that expect integers
      If function expects a pointer the verifier allows only that type of pointer.
      Like 1st argument of bpf_map_lookup_elem() must be pointer to map.
      (applies to non-root as well)
    
    unpriv: indirectly pass pointer on stack to helper function
      checks that pointer stored into stack cannot be used as part of key
      passed into bpf_map_lookup_elem()
    
    unpriv: mangle pointer on stack 1
    unpriv: mangle pointer on stack 2
      checks that writing into stack slot that already contains a pointer
      is disallowed
    
    unpriv: read pointer from stack in small chunks
      checks that < 8 byte read from stack slot that contains a pointer is
      disallowed
    
    unpriv: write pointer into ctx
      checks that storing pointers into skb->fields is disallowed
    
    unpriv: write pointer into map elem value
      checks that storing pointers into element values is disallowed
      For example:
      int bpf_prog(struct __sk_buff *skb)
      {
        u32 key = 0;
        u64 *value = bpf_map_lookup_elem(&map, &key);
        if (value)
           *value = (u64) skb;
      }
      will be rejected.
    
    unpriv: partial copy of pointer
      checks that doing 32-bit register mov from register containing
      a pointer is disallowed
    
    unpriv: pass pointer to tail_call
      checks that passing pointer as an index into bpf_tail_call
      is disallowed
    
    unpriv: cmp map pointer with zero
      checks that comparing map pointer with constant is disallowed
    
    unpriv: write into frame pointer
      checks that frame pointer is read-only (applies to root too)
    
    unpriv: cmp of frame pointer
      checks that R10 cannot be using in comparison
    
    unpriv: cmp of stack pointer
      checks that Rx = R10 - imm is ok, but comparing Rx is not
    
    unpriv: obfuscate stack pointer
      checks that Rx = R10 - imm is ok, but Rx -= imm is not
    Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    bf508877
libbpf.h 5.12 KB