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 14:19:32
Last Modify:2022-05-19 20:02:10 Copyright©Brick
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函数名称：vert load instructions that access fields of a context type into a* sequence of instructions that access fields of the underlying structure:* struct __sk_buff -> struct sk_buff* struct bpf_sock_ops -> struct sock

函数原型：static int convert_ctx_accesses(struct bpf_verifier_env *env)

返回类型：int

参数：

类型参数名称
struct bpf_verifier_env *env
8748  ops等于ops
8749  delta等于0
8750  insn_cnt等于 Number of filter blocks
8757  如果gen_prologue或seen_direct_write则
8758  如果非gen_prologue则
8759  verbose(env, "bpf verifier is misconfigured\n")
8760  返回:负EINVAL
8762  cnt等于gen_prologue(insn_buf, seen_direct_write, BPF program being verified )
8764  如果cnt大于等于ARRAY_SIZE - get the number of elements in array @arr*@arr: array to be sized(insn_buf)则
8765  verbose(env, "bpf verifier is misconfigured\n")
8766  返回:负EINVAL
8767  否则如果cnt则
8768  new_prog等于bpf_patch_insn_data(env, 0, insn_buf, cnt)
8769  如果非new_prog则返回:负ENOMEM
8772  BPF program being verified 等于new_prog
8773  delta加等于cnt减1
8777  如果bpf_prog_is_dev_bound( Auxiliary fields )则返回:0
8780  insn等于insnsi加delta
8782  以i小于insn_cnt循环
8785  如果 opcode 恒等于BPF_LDX按位或BPF_MEM按位或8-bit 的值或 opcode 恒等于BPF_LDX按位或BPF_MEM按位或16-bit 的值或 opcode 恒等于BPF_LDX按位或BPF_MEM按位或32-bit 的值或 opcode 恒等于BPF_LDX按位或BPF_MEM按位或double word (64-bit) 的值则type等于BPF_READ
8790  否则如果 opcode 恒等于BPF_STX按位或BPF_MEM按位或8-bit 的值或 opcode 恒等于BPF_STX按位或BPF_MEM按位或16-bit 的值或 opcode 恒等于BPF_STX按位或BPF_MEM按位或32-bit 的值或 opcode 恒等于BPF_STX按位或BPF_MEM按位或double word (64-bit) 的值则type等于BPF_WRITE
8795  否则继续下一循环
8798  如果type恒等于BPF_WRITE且 stack slot to be cleared 则
8800  struct bpf_insn patch[] = {Memory store, *(uint *) (dst_reg + off16) = imm32 (double word (64-bit) , BPF_REG_FP, stack slot to be cleared , 0), * insn, }
8815  cnt等于ARRAY_SIZE - get the number of elements in array @arr*@arr: array to be sized(patch)
8816  new_prog等于bpf_patch_insn_data(env, i + delta, patch, cnt)
8817  如果非new_prog则返回:负ENOMEM
8820  delta加等于cnt减1
8821  BPF program being verified 等于new_prog
8822  insn等于insnsi加i加delta
8823  继续下一循环
8827  当: pointer type for load/store insns 恒等于g points to bpf_context
8828  如果非convert_ctx_access则继续下一循环
8830  convert_ctx_access等于convert_ctx_access
8831  退出
8832  当: pointer type for load/store insns 恒等于g points to struct bpf_sock
8833  当: pointer type for load/store insns 恒等于g points to sock_common
8836  当: pointer type for load/store insns 恒等于g points to struct tcp_sock
8839  当: pointer type for load/store insns 恒等于g points to struct xdp_sock
8842  当: pointer type for load/store insns 恒等于g points to kernel struct
8843  如果type恒等于BPF_WRITE则
8844  verbose(env, "Writes through BTF pointers are not allowed\n")
8845  返回:负EINVAL
8847  opcode 等于BPF_LDX按位或unused opcode to mark special load instruction. Same as BPF_ABS 按位或ld/ldx fields ( opcode )
8848  num_exentries自加
8849  继续下一循环
8850  默认
8851  继续下一循环
8854  ctx_field_size等于 the ctx field size for load insn, maybe 0
8855  size等于BPF_LDST_BYTES(insn)
8862  is_narrower_load等于size小于ctx_field_size
8863  size_default等于bpf_ctx_off_adjust_machine(ctx_field_size)
8864  off等于 signed offset
8865  如果is_narrower_load则
8868  如果type恒等于BPF_WRITE则
8869  verbose(env, "bpf verifier narrow ctx access misconfigured\n")
8870  返回:负EINVAL
8873  size_code等于16-bit
8874  如果ctx_field_size恒等于4则size_code等于32-bit
8876  否则如果ctx_field_size恒等于8则size_code等于double word (64-bit)
8879  signed offset 等于off按位与size_default减1的差的反
8880  opcode 等于BPF_LDX按位或BPF_MEM按位或size_code
8883  target_size等于0
8884  cnt等于convert_ctx_access(type, insn, insn_buf, BPF program being verified , & target_size)
8886  如果cnt恒等于0或cnt大于等于ARRAY_SIZE - get the number of elements in array @arr*@arr: array to be sized(insn_buf)或ctx_field_size且非target_size则
8888  verbose(env, "bpf verifier is misconfigured\n")
8889  返回:负EINVAL
8892  如果is_narrower_load且size小于target_size则
8912  new_prog等于bpf_patch_insn_data(env, i + delta, insn_buf, cnt)
8913  如果非new_prog则返回:负ENOMEM
8916  delta加等于cnt减1
8919  BPF program being verified 等于new_prog
8920  insn等于insnsi加i加delta
8923  返回:0
调用者
名称描述
bpf_check