summaryrefslogtreecommitdiff
path: root/net/core/filter.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/core/filter.c')
-rw-r--r--net/core/filter.c373
1 files changed, 169 insertions, 204 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index c1ee800bc080..a44d27f9f0f0 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -37,6 +37,55 @@
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <linux/filter.h>
+#include <linux/reciprocal_div.h>
+
+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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-20 09:22:33 +0000