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, filter->len);
+
err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
}
rcu_read_unlock_bh();
*/
unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
{
- struct sock_filter *fentry; /* We walk down these */
void *ptr;
u32 A = 0; /* Accumulator */
u32 X = 0; /* Index Register */
u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */
+ 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++) {
- fentry = &filter[pc];
+ const struct sock_filter *fentry = &filter[pc];
+ u32 f_k = fentry->k;
switch (fentry->code) {
case BPF_S_ALU_ADD_X:
A += X;
continue;
case BPF_S_ALU_ADD_K:
- A += fentry->k;
+ A += f_k;
continue;
case BPF_S_ALU_SUB_X:
A -= X;
continue;
case BPF_S_ALU_SUB_K:
- A -= fentry->k;
+ A -= f_k;
continue;
case BPF_S_ALU_MUL_X:
A *= X;
continue;
case BPF_S_ALU_MUL_K:
- A *= fentry->k;
+ A *= f_k;
continue;
case BPF_S_ALU_DIV_X:
if (X == 0)
A /= X;
continue;
case BPF_S_ALU_DIV_K:
- A /= fentry->k;
+ A /= f_k;
continue;
case BPF_S_ALU_AND_X:
A &= X;
continue;
case BPF_S_ALU_AND_K:
- A &= fentry->k;
+ A &= f_k;
continue;
case BPF_S_ALU_OR_X:
A |= X;
continue;
case BPF_S_ALU_OR_K:
- A |= fentry->k;
+ A |= f_k;
continue;
case BPF_S_ALU_LSH_X:
A <<= X;
continue;
case BPF_S_ALU_LSH_K:
- A <<= fentry->k;
+ A <<= f_k;
continue;
case BPF_S_ALU_RSH_X:
A >>= X;
continue;
case BPF_S_ALU_RSH_K:
- A >>= fentry->k;
+ A >>= f_k;
continue;
case BPF_S_ALU_NEG:
A = -A;
continue;
case BPF_S_JMP_JA:
- pc += fentry->k;
+ pc += f_k;
continue;
case BPF_S_JMP_JGT_K:
- pc += (A > fentry->k) ? fentry->jt : fentry->jf;
+ pc += (A > f_k) ? fentry->jt : fentry->jf;
continue;
case BPF_S_JMP_JGE_K:
- pc += (A >= fentry->k) ? fentry->jt : fentry->jf;
+ pc += (A >= f_k) ? fentry->jt : fentry->jf;
continue;
case BPF_S_JMP_JEQ_K:
- pc += (A == fentry->k) ? fentry->jt : fentry->jf;
+ pc += (A == f_k) ? fentry->jt : fentry->jf;
continue;
case BPF_S_JMP_JSET_K:
- pc += (A & fentry->k) ? fentry->jt : fentry->jf;
+ pc += (A & f_k) ? fentry->jt : fentry->jf;
continue;
case BPF_S_JMP_JGT_X:
pc += (A > X) ? fentry->jt : fentry->jf;
pc += (A & X) ? fentry->jt : fentry->jf;
continue;
case BPF_S_LD_W_ABS:
- k = fentry->k;
+ k = f_k;
load_w:
ptr = load_pointer(skb, k, 4, &tmp);
if (ptr != NULL) {
}
break;
case BPF_S_LD_H_ABS:
- k = fentry->k;
+ k = f_k;
load_h:
ptr = load_pointer(skb, k, 2, &tmp);
if (ptr != NULL) {
}
break;
case BPF_S_LD_B_ABS:
- k = fentry->k;
+ k = f_k;
load_b:
ptr = load_pointer(skb, k, 1, &tmp);
if (ptr != NULL) {
X = skb->len;
continue;
case BPF_S_LD_W_IND:
- k = X + fentry->k;
+ k = X + f_k;
goto load_w;
case BPF_S_LD_H_IND:
- k = X + fentry->k;
+ k = X + f_k;
goto load_h;
case BPF_S_LD_B_IND:
- k = X + fentry->k;
+ k = X + f_k;
goto load_b;
case BPF_S_LDX_B_MSH:
- ptr = load_pointer(skb, fentry->k, 1, &tmp);
+ ptr = load_pointer(skb, f_k, 1, &tmp);
if (ptr != NULL) {
X = (*(u8 *)ptr & 0xf) << 2;
continue;
}
return 0;
case BPF_S_LD_IMM:
- A = fentry->k;
+ A = f_k;
continue;
case BPF_S_LDX_IMM:
- X = fentry->k;
+ X = f_k;
continue;
case BPF_S_LD_MEM:
- A = mem[fentry->k];
+ A = (memvalid & (1UL << f_k)) ?
+ mem[f_k] : 0;
continue;
case BPF_S_LDX_MEM:
- X = mem[fentry->k];
+ X = (memvalid & (1UL << f_k)) ?
+ mem[f_k] : 0;
continue;
case BPF_S_MISC_TAX:
X = A;
A = X;
continue;
case BPF_S_RET_K:
- return fentry->k;
+ return f_k;
case BPF_S_RET_A:
return A;
case BPF_S_ST:
- mem[fentry->k] = A;
+ memvalid |= 1UL << f_k;
+ mem[f_k] = A;
continue;
case BPF_S_STX:
- mem[fentry->k] = X;
+ memvalid |= 1UL << f_k;
+ mem[f_k] = X;
continue;
default:
WARN_ON(1);
*/
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 + 1,
+ [BPF_ALU|BPF_ADD|BPF_X] = BPF_S_ALU_ADD_X + 1,
+ [BPF_ALU|BPF_SUB|BPF_K] = BPF_S_ALU_SUB_K + 1,
+ [BPF_ALU|BPF_SUB|BPF_X] = BPF_S_ALU_SUB_X + 1,
+ [BPF_ALU|BPF_MUL|BPF_K] = BPF_S_ALU_MUL_K + 1,
+ [BPF_ALU|BPF_MUL|BPF_X] = BPF_S_ALU_MUL_X + 1,
+ [BPF_ALU|BPF_DIV|BPF_X] = BPF_S_ALU_DIV_X + 1,
+ [BPF_ALU|BPF_AND|BPF_K] = BPF_S_ALU_AND_K + 1,
+ [BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X + 1,
+ [BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K + 1,
+ [BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X + 1,
+ [BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K + 1,
+ [BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X + 1,
+ [BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K + 1,
+ [BPF_ALU|BPF_RSH|BPF_X] = BPF_S_ALU_RSH_X + 1,
+ [BPF_ALU|BPF_NEG] = BPF_S_ALU_NEG + 1,
+ [BPF_LD|BPF_W|BPF_ABS] = BPF_S_LD_W_ABS + 1,
+ [BPF_LD|BPF_H|BPF_ABS] = BPF_S_LD_H_ABS + 1,
+ [BPF_LD|BPF_B|BPF_ABS] = BPF_S_LD_B_ABS + 1,
+ [BPF_LD|BPF_W|BPF_LEN] = BPF_S_LD_W_LEN + 1,
+ [BPF_LD|BPF_W|BPF_IND] = BPF_S_LD_W_IND + 1,
+ [BPF_LD|BPF_H|BPF_IND] = BPF_S_LD_H_IND + 1,
+ [BPF_LD|BPF_B|BPF_IND] = BPF_S_LD_B_IND + 1,
+ [BPF_LD|BPF_IMM] = BPF_S_LD_IMM + 1,
+ [BPF_LDX|BPF_W|BPF_LEN] = BPF_S_LDX_W_LEN + 1,
+ [BPF_LDX|BPF_B|BPF_MSH] = BPF_S_LDX_B_MSH + 1,
+ [BPF_LDX|BPF_IMM] = BPF_S_LDX_IMM + 1,
+ [BPF_MISC|BPF_TAX] = BPF_S_MISC_TAX + 1,
+ [BPF_MISC|BPF_TXA] = BPF_S_MISC_TXA + 1,
+ [BPF_RET|BPF_K] = BPF_S_RET_K + 1,
+ [BPF_RET|BPF_A] = BPF_S_RET_A + 1,
+ [BPF_ALU|BPF_DIV|BPF_K] = BPF_S_ALU_DIV_K + 1,
+ [BPF_LD|BPF_MEM] = BPF_S_LD_MEM + 1,
+ [BPF_LDX|BPF_MEM] = BPF_S_LDX_MEM + 1,
+ [BPF_ST] = BPF_S_ST + 1,
+ [BPF_STX] = BPF_S_STX + 1,
+ [BPF_JMP|BPF_JA] = BPF_S_JMP_JA + 1,
+ [BPF_JMP|BPF_JEQ|BPF_K] = BPF_S_JMP_JEQ_K + 1,
+ [BPF_JMP|BPF_JEQ|BPF_X] = BPF_S_JMP_JEQ_X + 1,
+ [BPF_JMP|BPF_JGE|BPF_K] = BPF_S_JMP_JGE_K + 1,
+ [BPF_JMP|BPF_JGE|BPF_X] = BPF_S_JMP_JGE_X + 1,
+ [BPF_JMP|BPF_JGT|BPF_K] = BPF_S_JMP_JGT_K + 1,
+ [BPF_JMP|BPF_JGT|BPF_X] = BPF_S_JMP_JGT_X + 1,
+ [BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K + 1,
+ [BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X + 1,
+ };
int pc;
if (flen == 0 || flen > BPF_MAXINSNS)
/* 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];
+ /* Undo the '+ 1' in codes[] after validation. */
+ 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;
- 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,
*/
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:
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 */
case BPF_S_RET_K:
case BPF_S_RET_A:
return 0;
- break;
- default:
- return -EINVAL;
- }
+ }
+ return -EINVAL;
}
EXPORT_SYMBOL(sk_chk_filter);
return err;
}
- rcu_read_lock_bh();
- old_fp = rcu_dereference_bh(sk->sk_filter);
+ old_fp = rcu_dereference_protected(sk->sk_filter,
+ sock_owned_by_user(sk));
rcu_assign_pointer(sk->sk_filter, fp);
- rcu_read_unlock_bh();
if (old_fp)
sk_filter_delayed_uncharge(sk, old_fp);
int ret = -ENOENT;
struct sk_filter *filter;
- rcu_read_lock_bh();
- filter = rcu_dereference_bh(sk->sk_filter);
+ filter = rcu_dereference_protected(sk->sk_filter,
+ sock_owned_by_user(sk));
if (filter) {
rcu_assign_pointer(sk->sk_filter, NULL);
sk_filter_delayed_uncharge(sk, filter);
ret = 0;
}
- rcu_read_unlock_bh();
return ret;
}
EXPORT_SYMBOL_GPL(sk_detach_filter);
git://bbs.cooldavid.org / net-next-2.6.git / blobdiff