bpf: fix potential 32-bit overflow when accessing ARRAY map element
If BPF array map is bigger than 4GB, element pointer calculation can overflow because both index and elem_size are u32. Fix this everywhere by forcing 64-bit multiplication. Extract this formula into separate small helper and use it consistently in various places. Speculative-preventing formula utilizing index_mask trick is left as is, but explicit u64 casts are added in both places. Fixes: c85d6913 ("bpf: move memory size checks to bpf_map_charge_init()") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220715053146.1291891-2-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>
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