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pathological bpf programs may try to force verifier to explode in the number of branch states: 20: (d5) if r1 s<= 0x24000028 goto pc+0 21: (b5) if r0 <= 0xe1fa20 goto pc+2 22: (d5) if r1 s<= 0x7e goto pc+0 23: (b5) if r0 <= 0xe880e000 goto pc+0 24: (c5) if r0 s< 0x2100ecf4 goto pc+0 25: (d5) if r1 s<= 0xe880e000 goto pc+1 26: (c5) if r0 s< 0xf4041810 goto pc+0 27: (d5) if r1 s<= 0x1e007e goto pc+0 28: (b5) if r0 <= 0xe86be000 goto pc+0 29: (07) r0 += 16614 30: (c5) if r0 s< 0x6d0020da goto pc+0 31: (35) if r0 >= 0x2100ecf4 goto pc+0 Teach verifier to recognize always taken and always not taken branches. This analysis is already done for == and != comparison. Expand it to all other branches. It also helps real bpf programs to be verified faster: before after bpf_lb-DLB_L3.o 2003 1940 bpf_lb-DLB_L4.o 3173 3089 bpf_lb-DUNKNOWN.o 1080 1065 bpf_lxc-DDROP_ALL.o 29584 28052 bpf_lxc-DUNKNOWN.o 36916 35487 bpf_netdev.o 11188 10864 bpf_overlay.o 6679 6643 bpf_lcx_jit.o 39555 38437 Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> |
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.. | ||
arraymap.c | ||
bpf_lru_list.c | ||
bpf_lru_list.h | ||
btf.c | ||
cgroup.c | ||
core.c | ||
cpumap.c | ||
devmap.c | ||
disasm.c | ||
disasm.h | ||
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 | ||
tnum.c | ||
verifier.c | ||
xskmap.c |