bpf: restrict map value pointer arithmetic for unprivileged
Restrict map value pointer arithmetic for unprivileged users in that arithmetic itself must not go out of bounds as opposed to the actual access later on. Therefore after each adjust_ptr_min_max_vals() with a map value pointer as a destination it will simulate a check_map_access() of 1 byte on the destination and once that fails the program is rejected for unprivileged program loads. We use this later on for masking any pointer arithmetic with the remainder of the map value space. The likelihood of breaking any existing real-world unprivileged eBPF program is very small for this corner case. Signed-off-by:Daniel Borkmann <daniel@iogearbox.net> Acked-by:
Alexei Starovoitov <ast@kernel.org> Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
parent
9b73bfdd
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