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Currently, for all op verification we call __red_deduce_bounds() and __red_bound_offset() but we only call __update_reg_bounds() in bitwise ops. However, we could benefit from calling __update_reg_bounds() in BPF_ADD, BPF_SUB, and BPF_MUL cases as well. For example, a register with state 'R1_w=invP0' when we subtract from it, w1 -= 2 Before coerce we will now have an smin_value=S64_MIN, smax_value=U64_MAX and unsigned bounds umin_value=0, umax_value=U64_MAX. These will then be clamped to S32_MIN, U32_MAX values by coerce in the case of alu32 op as done in above example. However tnum will be a constant because the ALU op is done on a constant. Without update_reg_bounds() we have a scenario where tnum is a const but our unsigned bounds do not reflect this. By calling update_reg_bounds after coerce to 32bit we further refine the umin_value to U64_MAX in the alu64 case or U32_MAX in the alu32 case above. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/158507151689.15666.566796274289413203.stgit@john-Precision-5820-Tower |
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| .. | ||
| arraymap.c | ||
| bpf_lru_list.c | ||
| bpf_lru_list.h | ||
| bpf_struct_ops.c | ||
| bpf_struct_ops_types.h | ||
| btf.c | ||
| cgroup.c | ||
| core.c | ||
| cpumap.c | ||
| devmap.c | ||
| disasm.c | ||
| disasm.h | ||
| dispatcher.c | ||
| hashtab.c | ||
| helpers.c | ||
| inode.c | ||
| local_storage.c | ||
| lpm_trie.c | ||
| Makefile | ||
| map_in_map.c | ||
| map_in_map.h | ||
| offload.c | ||
| percpu_freelist.c | ||
| percpu_freelist.h | ||
| queue_stack_maps.c | ||
| reuseport_array.c | ||
| stackmap.c | ||
| syscall.c | ||
| sysfs_btf.c | ||
| tnum.c | ||
| trampoline.c | ||
| verifier.c | ||
| xskmap.c | ||