diff options
Diffstat (limited to 'arch/x86/net/bpf_jit.S')
| -rw-r--r-- | arch/x86/net/bpf_jit.S | 122 |
1 files changed, 91 insertions, 31 deletions
diff --git a/arch/x86/net/bpf_jit.S b/arch/x86/net/bpf_jit.S index 66870223f8c5..877b9a1b2152 100644 --- a/arch/x86/net/bpf_jit.S +++ b/arch/x86/net/bpf_jit.S @@ -18,17 +18,17 @@ * r9d : hlen = skb->len - skb->data_len */ #define SKBDATA %r8 - -sk_load_word_ind: - .globl sk_load_word_ind - - add %ebx,%esi /* offset += X */ -# test %esi,%esi /* if (offset < 0) goto bpf_error; */ - js bpf_error +#define SKF_MAX_NEG_OFF $(-0x200000) /* SKF_LL_OFF from filter.h */ sk_load_word: .globl sk_load_word + test %esi,%esi + js bpf_slow_path_word_neg + +sk_load_word_positive_offset: + .globl sk_load_word_positive_offset + mov %r9d,%eax # hlen sub %esi,%eax # hlen - offset cmp $3,%eax @@ -37,16 +37,15 @@ sk_load_word: bswap %eax /* ntohl() */ ret - -sk_load_half_ind: - .globl sk_load_half_ind - - add %ebx,%esi /* offset += X */ - js bpf_error - sk_load_half: .globl sk_load_half + test %esi,%esi + js bpf_slow_path_half_neg + +sk_load_half_positive_offset: + .globl sk_load_half_positive_offset + mov %r9d,%eax sub %esi,%eax # hlen - offset cmp $1,%eax @@ -55,14 +54,15 @@ sk_load_half: rol $8,%ax # ntohs() ret -sk_load_byte_ind: - .globl sk_load_byte_ind - add %ebx,%esi /* offset += X */ - js bpf_error - sk_load_byte: .globl sk_load_byte + test %esi,%esi + js bpf_slow_path_byte_neg + +sk_load_byte_positive_offset: + .globl sk_load_byte_positive_offset + cmp %esi,%r9d /* if (offset >= hlen) goto bpf_slow_path_byte */ jle bpf_slow_path_byte movzbl (SKBDATA,%rsi),%eax @@ -73,25 +73,21 @@ sk_load_byte: * * Implements BPF_S_LDX_B_MSH : ldxb 4*([offset]&0xf) * Must preserve A accumulator (%eax) - * Inputs : %esi is the offset value, already known positive + * Inputs : %esi is the offset value */ -ENTRY(sk_load_byte_msh) - CFI_STARTPROC +sk_load_byte_msh: + .globl sk_load_byte_msh + test %esi,%esi + js bpf_slow_path_byte_msh_neg + +sk_load_byte_msh_positive_offset: + .globl sk_load_byte_msh_positive_offset cmp %esi,%r9d /* if (offset >= hlen) goto bpf_slow_path_byte_msh */ jle bpf_slow_path_byte_msh movzbl (SKBDATA,%rsi),%ebx and $15,%bl shl $2,%bl ret - CFI_ENDPROC -ENDPROC(sk_load_byte_msh) - -bpf_error: -# force a return 0 from jit handler - xor %eax,%eax - mov -8(%rbp),%rbx - leaveq - ret /* rsi contains offset and can be scratched */ #define bpf_slow_path_common(LEN) \ @@ -138,3 +134,67 @@ bpf_slow_path_byte_msh: shl $2,%al xchg %eax,%ebx ret + +#define sk_negative_common(SIZE) \ + push %rdi; /* save skb */ \ + push %r9; \ + push SKBDATA; \ +/* rsi already has offset */ \ + mov $SIZE,%ecx; /* size */ \ + call bpf_internal_load_pointer_neg_helper; \ + test %rax,%rax; \ + pop SKBDATA; \ + pop %r9; \ + pop %rdi; \ + jz bpf_error + + +bpf_slow_path_word_neg: + cmp SKF_MAX_NEG_OFF, %esi /* test range */ + jl bpf_error /* offset lower -> error */ +sk_load_word_negative_offset: + .globl sk_load_word_negative_offset + sk_negative_common(4) + mov (%rax), %eax + bswap %eax + ret + +bpf_slow_path_half_neg: + cmp SKF_MAX_NEG_OFF, %esi + jl bpf_error +sk_load_half_negative_offset: + .globl sk_load_half_negative_offset + sk_negative_common(2) + mov (%rax),%ax + rol $8,%ax + movzwl %ax,%eax + ret + +bpf_slow_path_byte_neg: + cmp SKF_MAX_NEG_OFF, %esi + jl bpf_error +sk_load_byte_negative_offset: + .globl sk_load_byte_negative_offset + sk_negative_common(1) + movzbl (%rax), %eax + ret + +bpf_slow_path_byte_msh_neg: + cmp SKF_MAX_NEG_OFF, %esi + jl bpf_error +sk_load_byte_msh_negative_offset: + .globl sk_load_byte_msh_negative_offset + xchg %eax,%ebx /* dont lose A , X is about to be scratched */ + sk_negative_common(1) + movzbl (%rax),%eax + and $15,%al + shl $2,%al + xchg %eax,%ebx + ret + +bpf_error: +# force a return 0 from jit handler + xor %eax,%eax + mov -8(%rbp),%rbx + leaveq + ret |