函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\bpf\verifier.c Create Date:2022-07-27 14:14:51
Last Modify:2022-05-19 20:02:10 Copyright©Brick
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函数名称：WARNING: This function does calculations on 64-bit values, but the actual* execution may occur on 32-bit values. Therefore, things like bitshifts* need extra checks in the 32-bit case.

函数原型：static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, struct bpf_insn *insn, struct bpf_reg_state *dst_reg, struct bpf_reg_state src_reg)

返回类型：int

参数：

类型参数名称
struct bpf_verifier_env *env
struct bpf_insn *insn
struct bpf_reg_state *dst_reg
struct bpf_reg_statesrc_reg
4808  regs等于cur_regs(env)
4809  opcode等于alu/jmp fields ( opcode )
4813  insn_bitness等于如果Instruction classes ( opcode )恒等于alu mode in double word width 则64否则32
4814  dst等于 dest register
4817  如果insn_bitness恒等于32则
4822  runcate register to smaller size (in bytes)* must be called with size < BPF_REG_SIZE
4823  runcate register to smaller size (in bytes)* must be called with size < BPF_REG_SIZE
4826  smin_val等于 minimum possible (s64)value
4827  smax_val等于 maximum possible (s64)value
4828  umin_val等于 minimum possible (u64)value
4829  umax_val等于 maximum possible (u64)value
4830  src_known等于Returns true if @a is a known constant
4831  dst_known等于Returns true if @a is a known constant
4833  如果src_known且smin_val不等于smax_val或umin_val不等于umax_val的值或smin_val大于smax_val或umin_val大于umax_val则
4838  Mark a register as having a completely unknown (scalar) value.
4839  返回:0
4842  如果非src_known且opcode不等于BPF_ADD且opcode不等于BPF_SUB且opcode不等于BPF_AND则
4844  Mark a register as having a completely unknown (scalar) value.
4845  返回:0
4849  当:opcode恒等于BPF_ADD
4850  ret等于sanitize_val_alu(env, insn)
4851  如果ret小于0则
4852  verbose(env, "R%d tried to add from different pointers or scalars\n", dst)
4853  返回:ret
4855  如果signed_add_overflows( minimum possible (s64)value , smin_val)或signed_add_overflows( maximum possible (s64)value , smax_val)则
4859  否则
4863  如果 minimum possible (u64)value 加umin_val小于umin_val或 maximum possible (u64)value 加umax_val小于umax_val则
4867  否则
4871  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Add two tnums, return @a + @b
4872  退出
4873  当:opcode恒等于BPF_SUB
4874  ret等于sanitize_val_alu(env, insn)
4875  如果ret小于0则
4876  verbose(env, "R%d tried to sub from different pointers or scalars\n", dst)
4877  返回:ret
4879  如果signed_sub_overflows( minimum possible (s64)value , smax_val)或signed_sub_overflows( maximum possible (s64)value , smin_val)则
4884  否则
4888  如果 minimum possible (u64)value 小于umax_val则
4892  否则
4897  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Subtract two tnums, return @a - @b
4898  退出
4899  当:opcode恒等于BPF_MUL
4900  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Multiply two tnums, return @a *@b
4901  如果smin_val小于0或 minimum possible (s64)value 小于0则
4910  如果umax_val大于U32_MAX或 maximum possible (u64)value 大于U32_MAX则
4917  minimum possible (u64)value 乘等于umin_val
4918  maximum possible (u64)value 乘等于umax_val
4919  如果 maximum possible (u64)value 大于S64_MAX则
4923  否则
4927  退出
4928  当:opcode恒等于BPF_AND
4929  如果src_known且dst_known则
4937  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Bitwise-AND, return @a & @b
4938  minimum possible (u64)value 等于value
4939  maximum possible (u64)value 等于两数取小( maximum possible (u64)value , umax_val)
4940  如果 minimum possible (s64)value 小于0或smin_val小于0则
4946  否则
4954  Attempts to improve min/max values based on var_off information
4955  退出
4956  当:opcode恒等于BPF_OR
4957  如果src_known且dst_known则
4965  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Bitwise-OR, return @a | @b
4966  minimum possible (u64)value 等于两数取大( minimum possible (u64)value , umin_val)
4967  maximum possible (u64)value 等于value按位或mask
4969  如果 minimum possible (s64)value 小于0或smin_val小于0则
4975  否则
4983  Attempts to improve min/max values based on var_off information
4984  退出
4985  当:opcode恒等于BPF_LSH
4986  如果umax_val大于等于insn_bitness则
4996  minimum possible (s64)value 等于S64_MIN
4997  maximum possible (s64)value 等于S64_MAX
4999  如果 maximum possible (u64)value 大于1ULL左移63减umax_val位则
5002  否则
5006  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Shift a tnum left (by a fixed shift)
5008  Attempts to improve min/max values based on var_off information
5009  退出
5010  当:opcode恒等于BPF_RSH
5011  如果umax_val大于等于insn_bitness则
5032  minimum possible (s64)value 等于S64_MIN
5033  maximum possible (s64)value 等于S64_MAX
5034  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Shift (rsh) a tnum right (by a fixed shift)
5035  minimum possible (u64)value 右移等于umax_val位
5036  maximum possible (u64)value 右移等于umin_val位
5038  Attempts to improve min/max values based on var_off information
5039  退出
5040  当:opcode恒等于sign extending arithmetic shift right
5041  如果umax_val大于等于insn_bitness则
5052  如果insn_bitness恒等于32则
5055  否则
5060  For scalar types (SCALAR_VALUE), this represents our knowledge of * the actual value. * For pointer types, this represents the variable part of the offset * from the pointed-to object, and is shared with all bpf_reg_states * with the same id as us.等于Shift (arsh) a tnum right (by a fixed min_shift)
5066  minimum possible (u64)value 等于0
5067  maximum possible (u64)value 等于U64_MAX
5068  Attempts to improve min/max values based on var_off information
5069  退出
5070  默认
5071  mark_reg_unknown(env, regs, dest register )
5072  退出
5075  如果Instruction classes ( opcode )不等于alu mode in double word width 则
5077  runcate register to smaller size (in bytes)* must be called with size < BPF_REG_SIZE
5080  Uses signed min/max values to inform unsigned, and vice-versa
5081  Attempts to improve var_off based on unsigned min/max information
5082  返回:0
调用者
名称描述
adjust_reg_min_max_valsHandles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max* and var_off.