X-Git-Url: https://bbs.cooldavid.org/git/?p=net-next-2.6.git;a=blobdiff_plain;f=net%2Fcore%2Ffilter.c;h=a44d27f9f0f0aa4975d95b8e8c56bebb3f0fda6b;hp=c1ee800bc080c3faf33033e1659021a0a356f7ce;hb=24912420e923d56461b400d83f250a31bed8a964;hpb=0302b8622ce696af1cda22fcf207d3793350e896 diff --git a/net/core/filter.c b/net/core/filter.c index c1ee800bc08..a44d27f9f0f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -37,6 +37,55 @@ #include #include #include +#include + +enum { + BPF_S_RET_K = 1, + BPF_S_RET_A, + BPF_S_ALU_ADD_K, + BPF_S_ALU_ADD_X, + BPF_S_ALU_SUB_K, + BPF_S_ALU_SUB_X, + BPF_S_ALU_MUL_K, + BPF_S_ALU_MUL_X, + BPF_S_ALU_DIV_X, + BPF_S_ALU_AND_K, + BPF_S_ALU_AND_X, + BPF_S_ALU_OR_K, + BPF_S_ALU_OR_X, + BPF_S_ALU_LSH_K, + BPF_S_ALU_LSH_X, + BPF_S_ALU_RSH_K, + BPF_S_ALU_RSH_X, + BPF_S_ALU_NEG, + BPF_S_LD_W_ABS, + BPF_S_LD_H_ABS, + BPF_S_LD_B_ABS, + BPF_S_LD_W_LEN, + BPF_S_LD_W_IND, + BPF_S_LD_H_IND, + BPF_S_LD_B_IND, + BPF_S_LD_IMM, + BPF_S_LDX_W_LEN, + BPF_S_LDX_B_MSH, + BPF_S_LDX_IMM, + BPF_S_MISC_TAX, + BPF_S_MISC_TXA, + BPF_S_ALU_DIV_K, + BPF_S_LD_MEM, + BPF_S_LDX_MEM, + BPF_S_ST, + BPF_S_STX, + BPF_S_JMP_JA, + BPF_S_JMP_JEQ_K, + BPF_S_JMP_JEQ_X, + BPF_S_JMP_JGE_K, + BPF_S_JMP_JGE_X, + BPF_S_JMP_JGT_K, + BPF_S_JMP_JGT_X, + BPF_S_JMP_JSET_K, + BPF_S_JMP_JSET_X, +}; /* No hurry in this branch */ static void *__load_pointer(struct sk_buff *skb, int k) @@ -89,7 +138,7 @@ int sk_filter(struct sock *sk, struct sk_buff *skb) rcu_read_lock_bh(); filter = rcu_dereference_bh(sk->sk_filter); if (filter) { - unsigned int pkt_len = sk_run_filter(skb, filter->insns, filter->len); + unsigned int pkt_len = sk_run_filter(skb, filter->insns); err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM; } @@ -103,14 +152,15 @@ EXPORT_SYMBOL(sk_filter); * sk_run_filter - run a filter on a socket * @skb: buffer to run the filter on * @filter: filter to apply - * @flen: length of filter * * Decode and apply filter instructions to the skb->data. - * Return length to keep, 0 for none. skb is the data we are - * filtering, filter is the array of filter instructions, and - * len is the number of filter blocks in the array. + * Return length to keep, 0 for none. @skb is the data we are + * filtering, @filter is the array of filter instructions. + * Because all jumps are guaranteed to be before last instruction, + * and last instruction guaranteed to be a RET, we dont need to check + * flen. (We used to pass to this function the length of filter) */ -unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen) +unsigned int sk_run_filter(struct sk_buff *skb, const struct sock_filter *fentry) { void *ptr; u32 A = 0; /* Accumulator */ @@ -119,34 +169,36 @@ unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int unsigned long memvalid = 0; u32 tmp; int k; - int pc; BUILD_BUG_ON(BPF_MEMWORDS > BITS_PER_LONG); /* * Process array of filter instructions. */ - for (pc = 0; pc < flen; pc++) { - const struct sock_filter *fentry = &filter[pc]; - u32 f_k = fentry->k; + for (;; fentry++) { +#if defined(CONFIG_X86_32) +#define K (fentry->k) +#else + const u32 K = fentry->k; +#endif switch (fentry->code) { case BPF_S_ALU_ADD_X: A += X; continue; case BPF_S_ALU_ADD_K: - A += f_k; + A += K; continue; case BPF_S_ALU_SUB_X: A -= X; continue; case BPF_S_ALU_SUB_K: - A -= f_k; + A -= K; continue; case BPF_S_ALU_MUL_X: A *= X; continue; case BPF_S_ALU_MUL_K: - A *= f_k; + A *= K; continue; case BPF_S_ALU_DIV_X: if (X == 0) @@ -154,64 +206,64 @@ unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int A /= X; continue; case BPF_S_ALU_DIV_K: - A /= f_k; + A = reciprocal_divide(A, K); continue; case BPF_S_ALU_AND_X: A &= X; continue; case BPF_S_ALU_AND_K: - A &= f_k; + A &= K; continue; case BPF_S_ALU_OR_X: A |= X; continue; case BPF_S_ALU_OR_K: - A |= f_k; + A |= K; continue; case BPF_S_ALU_LSH_X: A <<= X; continue; case BPF_S_ALU_LSH_K: - A <<= f_k; + A <<= K; continue; case BPF_S_ALU_RSH_X: A >>= X; continue; case BPF_S_ALU_RSH_K: - A >>= f_k; + A >>= K; continue; case BPF_S_ALU_NEG: A = -A; continue; case BPF_S_JMP_JA: - pc += f_k; + fentry += K; continue; case BPF_S_JMP_JGT_K: - pc += (A > f_k) ? fentry->jt : fentry->jf; + fentry += (A > K) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JGE_K: - pc += (A >= f_k) ? fentry->jt : fentry->jf; + fentry += (A >= K) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JEQ_K: - pc += (A == f_k) ? fentry->jt : fentry->jf; + fentry += (A == K) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JSET_K: - pc += (A & f_k) ? fentry->jt : fentry->jf; + fentry += (A & K) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JGT_X: - pc += (A > X) ? fentry->jt : fentry->jf; + fentry += (A > X) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JGE_X: - pc += (A >= X) ? fentry->jt : fentry->jf; + fentry += (A >= X) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JEQ_X: - pc += (A == X) ? fentry->jt : fentry->jf; + fentry += (A == X) ? fentry->jt : fentry->jf; continue; case BPF_S_JMP_JSET_X: - pc += (A & X) ? fentry->jt : fentry->jf; + fentry += (A & X) ? fentry->jt : fentry->jf; continue; case BPF_S_LD_W_ABS: - k = f_k; + k = K; load_w: ptr = load_pointer(skb, k, 4, &tmp); if (ptr != NULL) { @@ -220,7 +272,7 @@ load_w: } break; case BPF_S_LD_H_ABS: - k = f_k; + k = K; load_h: ptr = load_pointer(skb, k, 2, &tmp); if (ptr != NULL) { @@ -229,7 +281,7 @@ load_h: } break; case BPF_S_LD_B_ABS: - k = f_k; + k = K; load_b: ptr = load_pointer(skb, k, 1, &tmp); if (ptr != NULL) { @@ -244,34 +296,34 @@ load_b: X = skb->len; continue; case BPF_S_LD_W_IND: - k = X + f_k; + k = X + K; goto load_w; case BPF_S_LD_H_IND: - k = X + f_k; + k = X + K; goto load_h; case BPF_S_LD_B_IND: - k = X + f_k; + k = X + K; goto load_b; case BPF_S_LDX_B_MSH: - ptr = load_pointer(skb, f_k, 1, &tmp); + ptr = load_pointer(skb, K, 1, &tmp); if (ptr != NULL) { X = (*(u8 *)ptr & 0xf) << 2; continue; } return 0; case BPF_S_LD_IMM: - A = f_k; + A = K; continue; case BPF_S_LDX_IMM: - X = f_k; + X = K; continue; case BPF_S_LD_MEM: - A = (memvalid & (1UL << f_k)) ? - mem[f_k] : 0; + A = (memvalid & (1UL << K)) ? + mem[K] : 0; continue; case BPF_S_LDX_MEM: - X = (memvalid & (1UL << f_k)) ? - mem[f_k] : 0; + X = (memvalid & (1UL << K)) ? + mem[K] : 0; continue; case BPF_S_MISC_TAX: X = A; @@ -280,16 +332,16 @@ load_b: A = X; continue; case BPF_S_RET_K: - return f_k; + return K; case BPF_S_RET_A: return A; case BPF_S_ST: - memvalid |= 1UL << f_k; - mem[f_k] = A; + memvalid |= 1UL << K; + mem[K] = A; continue; case BPF_S_STX: - memvalid |= 1UL << f_k; - mem[f_k] = X; + memvalid |= 1UL << K; + mem[K] = X; continue; default: WARN_ON(1); @@ -383,7 +435,57 @@ EXPORT_SYMBOL(sk_run_filter); */ int sk_chk_filter(struct sock_filter *filter, int flen) { - struct sock_filter *ftest; + /* + * Valid instructions are initialized to non-0. + * Invalid instructions are initialized to 0. + */ + static const u8 codes[] = { + [BPF_ALU|BPF_ADD|BPF_K] = BPF_S_ALU_ADD_K, + [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X, + [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K, + [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X, + [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K, + [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X, + [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X, + [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K, + [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X, + [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K, + [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X, + [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K, + [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X, + [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K, + [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X, + [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG, + [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS, + [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS, + [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS, + [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN, + [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND, + [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND, + [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND, + [BPF_LD|BPF_IMM] = BPF_S_LD_IMM, + [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN, + [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH, + [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM, + [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX, + [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA, + [BPF_RET|BPF_K] = BPF_S_RET_K, + [BPF_RET|BPF_A] = BPF_S_RET_A, + [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K, + [BPF_LD|BPF_MEM] = BPF_S_LD_MEM, + [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM, + [BPF_ST] = BPF_S_ST, + [BPF_STX] = BPF_S_STX, + [BPF_JMP|BPF_JA] = BPF_S_JMP_JA, + [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K, + [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X, + [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K, + [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X, + [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K, + [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X, + [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K, + [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X, + }; int pc; if (flen == 0 || flen > BPF_MAXINSNS) @@ -391,136 +493,31 @@ int sk_chk_filter(struct sock_filter *filter, int flen) /* check the filter code now */ for (pc = 0; pc < flen; pc++) { - ftest = &filter[pc]; - - /* Only allow valid instructions */ - switch (ftest->code) { - case BPF_ALU|BPF_ADD|BPF_K: - ftest->code = BPF_S_ALU_ADD_K; - break; - case BPF_ALU|BPF_ADD|BPF_X: - ftest->code = BPF_S_ALU_ADD_X; - break; - case BPF_ALU|BPF_SUB|BPF_K: - ftest->code = BPF_S_ALU_SUB_K; - break; - case BPF_ALU|BPF_SUB|BPF_X: - ftest->code = BPF_S_ALU_SUB_X; - break; - case BPF_ALU|BPF_MUL|BPF_K: - ftest->code = BPF_S_ALU_MUL_K; - break; - case BPF_ALU|BPF_MUL|BPF_X: - ftest->code = BPF_S_ALU_MUL_X; - break; - case BPF_ALU|BPF_DIV|BPF_X: - ftest->code = BPF_S_ALU_DIV_X; - break; - case BPF_ALU|BPF_AND|BPF_K: - ftest->code = BPF_S_ALU_AND_K; - break; - case BPF_ALU|BPF_AND|BPF_X: - ftest->code = BPF_S_ALU_AND_X; - break; - case BPF_ALU|BPF_OR|BPF_K: - ftest->code = BPF_S_ALU_OR_K; - break; - case BPF_ALU|BPF_OR|BPF_X: - ftest->code = BPF_S_ALU_OR_X; - break; - case BPF_ALU|BPF_LSH|BPF_K: - ftest->code = BPF_S_ALU_LSH_K; - break; - case BPF_ALU|BPF_LSH|BPF_X: - ftest->code = BPF_S_ALU_LSH_X; - break; - case BPF_ALU|BPF_RSH|BPF_K: - ftest->code = BPF_S_ALU_RSH_K; - break; - case BPF_ALU|BPF_RSH|BPF_X: - ftest->code = BPF_S_ALU_RSH_X; - break; - case BPF_ALU|BPF_NEG: - ftest->code = BPF_S_ALU_NEG; - break; - case BPF_LD|BPF_W|BPF_ABS: - ftest->code = BPF_S_LD_W_ABS; - break; - case BPF_LD|BPF_H|BPF_ABS: - ftest->code = BPF_S_LD_H_ABS; - break; - case BPF_LD|BPF_B|BPF_ABS: - ftest->code = BPF_S_LD_B_ABS; - break; - case BPF_LD|BPF_W|BPF_LEN: - ftest->code = BPF_S_LD_W_LEN; - break; - case BPF_LD|BPF_W|BPF_IND: - ftest->code = BPF_S_LD_W_IND; - break; - case BPF_LD|BPF_H|BPF_IND: - ftest->code = BPF_S_LD_H_IND; - break; - case BPF_LD|BPF_B|BPF_IND: - ftest->code = BPF_S_LD_B_IND; - break; - case BPF_LD|BPF_IMM: - ftest->code = BPF_S_LD_IMM; - break; - case BPF_LDX|BPF_W|BPF_LEN: - ftest->code = BPF_S_LDX_W_LEN; - break; - case BPF_LDX|BPF_B|BPF_MSH: - ftest->code = BPF_S_LDX_B_MSH; - break; - case BPF_LDX|BPF_IMM: - ftest->code = BPF_S_LDX_IMM; - break; - case BPF_MISC|BPF_TAX: - ftest->code = BPF_S_MISC_TAX; - break; - case BPF_MISC|BPF_TXA: - ftest->code = BPF_S_MISC_TXA; - break; - case BPF_RET|BPF_K: - ftest->code = BPF_S_RET_K; - break; - case BPF_RET|BPF_A: - ftest->code = BPF_S_RET_A; - break; + struct sock_filter *ftest = &filter[pc]; + u16 code = ftest->code; + if (code >= ARRAY_SIZE(codes)) + return -EINVAL; + code = codes[code]; + if (!code) + return -EINVAL; /* Some instructions need special checks */ - + switch (code) { + case BPF_S_ALU_DIV_K: /* check for division by zero */ - case BPF_ALU|BPF_DIV|BPF_K: if (ftest->k == 0) return -EINVAL; - ftest->code = BPF_S_ALU_DIV_K; - break; - - /* check for invalid memory addresses */ - case BPF_LD|BPF_MEM: - if (ftest->k >= BPF_MEMWORDS) - return -EINVAL; - ftest->code = BPF_S_LD_MEM; - break; - case BPF_LDX|BPF_MEM: - if (ftest->k >= BPF_MEMWORDS) - return -EINVAL; - ftest->code = BPF_S_LDX_MEM; - break; - case BPF_ST: - if (ftest->k >= BPF_MEMWORDS) - return -EINVAL; - ftest->code = BPF_S_ST; + ftest->k = reciprocal_value(ftest->k); break; - case BPF_STX: + case BPF_S_LD_MEM: + case BPF_S_LDX_MEM: + case BPF_S_ST: + case BPF_S_STX: + /* check for invalid memory addresses */ if (ftest->k >= BPF_MEMWORDS) return -EINVAL; - ftest->code = BPF_S_STX; break; - - case BPF_JMP|BPF_JA: + case BPF_S_JMP_JA: /* * Note, the large ftest->k might cause loops. * Compare this with conditional jumps below, @@ -528,40 +525,7 @@ int sk_chk_filter(struct sock_filter *filter, int flen) */ if (ftest->k >= (unsigned)(flen-pc-1)) return -EINVAL; - ftest->code = BPF_S_JMP_JA; - break; - - case BPF_JMP|BPF_JEQ|BPF_K: - ftest->code = BPF_S_JMP_JEQ_K; break; - case BPF_JMP|BPF_JEQ|BPF_X: - ftest->code = BPF_S_JMP_JEQ_X; - break; - case BPF_JMP|BPF_JGE|BPF_K: - ftest->code = BPF_S_JMP_JGE_K; - break; - case BPF_JMP|BPF_JGE|BPF_X: - ftest->code = BPF_S_JMP_JGE_X; - break; - case BPF_JMP|BPF_JGT|BPF_K: - ftest->code = BPF_S_JMP_JGT_K; - break; - case BPF_JMP|BPF_JGT|BPF_X: - ftest->code = BPF_S_JMP_JGT_X; - break; - case BPF_JMP|BPF_JSET|BPF_K: - ftest->code = BPF_S_JMP_JSET_K; - break; - case BPF_JMP|BPF_JSET|BPF_X: - ftest->code = BPF_S_JMP_JSET_X; - break; - - default: - return -EINVAL; - } - - /* for conditionals both must be safe */ - switch (ftest->code) { case BPF_S_JMP_JEQ_K: case BPF_S_JMP_JEQ_X: case BPF_S_JMP_JGE_K: @@ -570,10 +534,13 @@ int sk_chk_filter(struct sock_filter *filter, int flen) case BPF_S_JMP_JGT_X: case BPF_S_JMP_JSET_X: case BPF_S_JMP_JSET_K: + /* for conditionals both must be safe */ if (pc + ftest->jt + 1 >= flen || pc + ftest->jf + 1 >= flen) return -EINVAL; + break; } + ftest->code = code; } /* last instruction must be a RET code */ @@ -581,10 +548,8 @@ int sk_chk_filter(struct sock_filter *filter, int flen) case BPF_S_RET_K: case BPF_S_RET_A: return 0; - break; - default: - return -EINVAL; - } + } + return -EINVAL; } EXPORT_SYMBOL(sk_chk_filter);