/*
|
/*
|
* Linux Socket Filter - Kernel level socket filtering
|
* Linux Socket Filter - Kernel level socket filtering
|
*
|
*
|
* Author:
|
* Author:
|
* Jay Schulist <jschlst@samba.org>
|
* Jay Schulist <jschlst@samba.org>
|
*
|
*
|
* Based on the design of:
|
* Based on the design of:
|
* - The Berkeley Packet Filter
|
* - The Berkeley Packet Filter
|
*
|
*
|
* This program is free software; you can redistribute it and/or
|
* This program is free software; you can redistribute it and/or
|
* modify it under the terms of the GNU General Public License
|
* modify it under the terms of the GNU General Public License
|
* as published by the Free Software Foundation; either version
|
* as published by the Free Software Foundation; either version
|
* 2 of the License, or (at your option) any later version.
|
* 2 of the License, or (at your option) any later version.
|
*
|
*
|
* Andi Kleen - Fix a few bad bugs and races.
|
* Andi Kleen - Fix a few bad bugs and races.
|
*/
|
*/
|
|
|
#include <linux/config.h>
|
#include <linux/config.h>
|
#if defined(CONFIG_FILTER)
|
#if defined(CONFIG_FILTER)
|
|
|
#include <linux/module.h>
|
#include <linux/module.h>
|
#include <linux/types.h>
|
#include <linux/types.h>
|
#include <linux/sched.h>
|
#include <linux/sched.h>
|
#include <linux/mm.h>
|
#include <linux/mm.h>
|
#include <linux/fcntl.h>
|
#include <linux/fcntl.h>
|
#include <linux/socket.h>
|
#include <linux/socket.h>
|
#include <linux/in.h>
|
#include <linux/in.h>
|
#include <linux/inet.h>
|
#include <linux/inet.h>
|
#include <linux/netdevice.h>
|
#include <linux/netdevice.h>
|
#include <linux/if_packet.h>
|
#include <linux/if_packet.h>
|
#include <net/ip.h>
|
#include <net/ip.h>
|
#include <net/protocol.h>
|
#include <net/protocol.h>
|
#include <linux/skbuff.h>
|
#include <linux/skbuff.h>
|
#include <net/sock.h>
|
#include <net/sock.h>
|
#include <linux/errno.h>
|
#include <linux/errno.h>
|
#include <linux/timer.h>
|
#include <linux/timer.h>
|
#include <asm/system.h>
|
#include <asm/system.h>
|
#include <asm/uaccess.h>
|
#include <asm/uaccess.h>
|
#include <linux/filter.h>
|
#include <linux/filter.h>
|
|
|
/* No hurry in this branch */
|
/* No hurry in this branch */
|
|
|
static u8 *load_pointer(struct sk_buff *skb, int k)
|
static u8 *load_pointer(struct sk_buff *skb, int k)
|
{
|
{
|
u8 *ptr = NULL;
|
u8 *ptr = NULL;
|
|
|
if (k>=SKF_NET_OFF)
|
if (k>=SKF_NET_OFF)
|
ptr = skb->nh.raw + k - SKF_NET_OFF;
|
ptr = skb->nh.raw + k - SKF_NET_OFF;
|
else if (k>=SKF_LL_OFF)
|
else if (k>=SKF_LL_OFF)
|
ptr = skb->mac.raw + k - SKF_LL_OFF;
|
ptr = skb->mac.raw + k - SKF_LL_OFF;
|
|
|
if (ptr >= skb->head && ptr < skb->tail)
|
if (ptr >= skb->head && ptr < skb->tail)
|
return ptr;
|
return ptr;
|
return NULL;
|
return NULL;
|
}
|
}
|
|
|
/**
|
/**
|
* sk_run_filter - run a filter on a socket
|
* sk_run_filter - run a filter on a socket
|
* @skb: buffer to run the filter on
|
* @skb: buffer to run the filter on
|
* @filter: filter to apply
|
* @filter: filter to apply
|
* @flen: length of filter
|
* @flen: length of filter
|
*
|
*
|
* Decode and apply filter instructions to the skb->data.
|
* Decode and apply filter instructions to the skb->data.
|
* Return length to keep, 0 for none. skb is the data we are
|
* Return length to keep, 0 for none. skb is the data we are
|
* filtering, filter is the array of filter instructions, and
|
* filtering, filter is the array of filter instructions, and
|
* len is the number of filter blocks in the array.
|
* len is the number of filter blocks in the array.
|
*/
|
*/
|
|
|
int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
|
int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen)
|
{
|
{
|
unsigned char *data = skb->data;
|
unsigned char *data = skb->data;
|
/* len is UNSIGNED. Byte wide insns relies only on implicit
|
/* len is UNSIGNED. Byte wide insns relies only on implicit
|
type casts to prevent reading arbitrary memory locations.
|
type casts to prevent reading arbitrary memory locations.
|
*/
|
*/
|
unsigned int len = skb->len-skb->data_len;
|
unsigned int len = skb->len-skb->data_len;
|
struct sock_filter *fentry; /* We walk down these */
|
struct sock_filter *fentry; /* We walk down these */
|
u32 A = 0; /* Accumulator */
|
u32 A = 0; /* Accumulator */
|
u32 X = 0; /* Index Register */
|
u32 X = 0; /* Index Register */
|
u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */
|
u32 mem[BPF_MEMWORDS]; /* Scratch Memory Store */
|
int k;
|
int k;
|
int pc;
|
int pc;
|
|
|
/*
|
/*
|
* Process array of filter instructions.
|
* Process array of filter instructions.
|
*/
|
*/
|
|
|
for(pc = 0; pc < flen; pc++)
|
for(pc = 0; pc < flen; pc++)
|
{
|
{
|
fentry = &filter[pc];
|
fentry = &filter[pc];
|
|
|
switch(fentry->code)
|
switch(fentry->code)
|
{
|
{
|
case BPF_ALU|BPF_ADD|BPF_X:
|
case BPF_ALU|BPF_ADD|BPF_X:
|
A += X;
|
A += X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_ADD|BPF_K:
|
case BPF_ALU|BPF_ADD|BPF_K:
|
A += fentry->k;
|
A += fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_SUB|BPF_X:
|
case BPF_ALU|BPF_SUB|BPF_X:
|
A -= X;
|
A -= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_SUB|BPF_K:
|
case BPF_ALU|BPF_SUB|BPF_K:
|
A -= fentry->k;
|
A -= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_MUL|BPF_X:
|
case BPF_ALU|BPF_MUL|BPF_X:
|
A *= X;
|
A *= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_MUL|BPF_K:
|
case BPF_ALU|BPF_MUL|BPF_K:
|
A *= fentry->k;
|
A *= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_DIV|BPF_X:
|
case BPF_ALU|BPF_DIV|BPF_X:
|
if(X == 0)
|
if(X == 0)
|
return (0);
|
return (0);
|
A /= X;
|
A /= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_DIV|BPF_K:
|
case BPF_ALU|BPF_DIV|BPF_K:
|
if(fentry->k == 0)
|
if(fentry->k == 0)
|
return (0);
|
return (0);
|
A /= fentry->k;
|
A /= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_AND|BPF_X:
|
case BPF_ALU|BPF_AND|BPF_X:
|
A &= X;
|
A &= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_AND|BPF_K:
|
case BPF_ALU|BPF_AND|BPF_K:
|
A &= fentry->k;
|
A &= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_OR|BPF_X:
|
case BPF_ALU|BPF_OR|BPF_X:
|
A |= X;
|
A |= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_OR|BPF_K:
|
case BPF_ALU|BPF_OR|BPF_K:
|
A |= fentry->k;
|
A |= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_LSH|BPF_X:
|
case BPF_ALU|BPF_LSH|BPF_X:
|
A <<= X;
|
A <<= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_LSH|BPF_K:
|
case BPF_ALU|BPF_LSH|BPF_K:
|
A <<= fentry->k;
|
A <<= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_RSH|BPF_X:
|
case BPF_ALU|BPF_RSH|BPF_X:
|
A >>= X;
|
A >>= X;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_RSH|BPF_K:
|
case BPF_ALU|BPF_RSH|BPF_K:
|
A >>= fentry->k;
|
A >>= fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_ALU|BPF_NEG:
|
case BPF_ALU|BPF_NEG:
|
A = -A;
|
A = -A;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JA:
|
case BPF_JMP|BPF_JA:
|
pc += fentry->k;
|
pc += fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JGT|BPF_K:
|
case BPF_JMP|BPF_JGT|BPF_K:
|
pc += (A > fentry->k) ? fentry->jt : fentry->jf;
|
pc += (A > fentry->k) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JGE|BPF_K:
|
case BPF_JMP|BPF_JGE|BPF_K:
|
pc += (A >= fentry->k) ? fentry->jt : fentry->jf;
|
pc += (A >= fentry->k) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JEQ|BPF_K:
|
case BPF_JMP|BPF_JEQ|BPF_K:
|
pc += (A == fentry->k) ? fentry->jt : fentry->jf;
|
pc += (A == fentry->k) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JSET|BPF_K:
|
case BPF_JMP|BPF_JSET|BPF_K:
|
pc += (A & fentry->k) ? fentry->jt : fentry->jf;
|
pc += (A & fentry->k) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JGT|BPF_X:
|
case BPF_JMP|BPF_JGT|BPF_X:
|
pc += (A > X) ? fentry->jt : fentry->jf;
|
pc += (A > X) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JGE|BPF_X:
|
case BPF_JMP|BPF_JGE|BPF_X:
|
pc += (A >= X) ? fentry->jt : fentry->jf;
|
pc += (A >= X) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JEQ|BPF_X:
|
case BPF_JMP|BPF_JEQ|BPF_X:
|
pc += (A == X) ? fentry->jt : fentry->jf;
|
pc += (A == X) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_JMP|BPF_JSET|BPF_X:
|
case BPF_JMP|BPF_JSET|BPF_X:
|
pc += (A & X) ? fentry->jt : fentry->jf;
|
pc += (A & X) ? fentry->jt : fentry->jf;
|
continue;
|
continue;
|
|
|
case BPF_LD|BPF_W|BPF_ABS:
|
case BPF_LD|BPF_W|BPF_ABS:
|
k = fentry->k;
|
k = fentry->k;
|
load_w:
|
load_w:
|
if(k >= 0 && (unsigned int)(k+sizeof(u32)) <= len) {
|
if(k >= 0 && (unsigned int)(k+sizeof(u32)) <= len) {
|
A = ntohl(*(u32*)&data[k]);
|
A = ntohl(*(u32*)&data[k]);
|
continue;
|
continue;
|
}
|
}
|
if (k<0) {
|
if (k<0) {
|
u8 *ptr;
|
u8 *ptr;
|
|
|
if (k>=SKF_AD_OFF)
|
if (k>=SKF_AD_OFF)
|
break;
|
break;
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
A = ntohl(*(u32*)ptr);
|
A = ntohl(*(u32*)ptr);
|
continue;
|
continue;
|
}
|
}
|
} else {
|
} else {
|
u32 tmp;
|
u32 tmp;
|
if (!skb_copy_bits(skb, k, &tmp, 4)) {
|
if (!skb_copy_bits(skb, k, &tmp, 4)) {
|
A = ntohl(tmp);
|
A = ntohl(tmp);
|
continue;
|
continue;
|
}
|
}
|
}
|
}
|
return 0;
|
return 0;
|
|
|
case BPF_LD|BPF_H|BPF_ABS:
|
case BPF_LD|BPF_H|BPF_ABS:
|
k = fentry->k;
|
k = fentry->k;
|
load_h:
|
load_h:
|
if(k >= 0 && (unsigned int) (k + sizeof(u16)) <= len) {
|
if(k >= 0 && (unsigned int) (k + sizeof(u16)) <= len) {
|
A = ntohs(*(u16*)&data[k]);
|
A = ntohs(*(u16*)&data[k]);
|
continue;
|
continue;
|
}
|
}
|
if (k<0) {
|
if (k<0) {
|
u8 *ptr;
|
u8 *ptr;
|
|
|
if (k>=SKF_AD_OFF)
|
if (k>=SKF_AD_OFF)
|
break;
|
break;
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
A = ntohs(*(u16*)ptr);
|
A = ntohs(*(u16*)ptr);
|
continue;
|
continue;
|
}
|
}
|
} else {
|
} else {
|
u16 tmp;
|
u16 tmp;
|
if (!skb_copy_bits(skb, k, &tmp, 2)) {
|
if (!skb_copy_bits(skb, k, &tmp, 2)) {
|
A = ntohs(tmp);
|
A = ntohs(tmp);
|
continue;
|
continue;
|
}
|
}
|
}
|
}
|
return 0;
|
return 0;
|
|
|
case BPF_LD|BPF_B|BPF_ABS:
|
case BPF_LD|BPF_B|BPF_ABS:
|
k = fentry->k;
|
k = fentry->k;
|
load_b:
|
load_b:
|
if(k >= 0 && (unsigned int)k < len) {
|
if(k >= 0 && (unsigned int)k < len) {
|
A = data[k];
|
A = data[k];
|
continue;
|
continue;
|
}
|
}
|
if (k<0) {
|
if (k<0) {
|
u8 *ptr;
|
u8 *ptr;
|
|
|
if (k>=SKF_AD_OFF)
|
if (k>=SKF_AD_OFF)
|
break;
|
break;
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
if ((ptr = load_pointer(skb, k)) != NULL) {
|
A = *ptr;
|
A = *ptr;
|
continue;
|
continue;
|
}
|
}
|
} else {
|
} else {
|
u8 tmp;
|
u8 tmp;
|
if (!skb_copy_bits(skb, k, &tmp, 1)) {
|
if (!skb_copy_bits(skb, k, &tmp, 1)) {
|
A = tmp;
|
A = tmp;
|
continue;
|
continue;
|
}
|
}
|
}
|
}
|
return 0;
|
return 0;
|
|
|
case BPF_LD|BPF_W|BPF_LEN:
|
case BPF_LD|BPF_W|BPF_LEN:
|
A = len;
|
A = len;
|
continue;
|
continue;
|
|
|
case BPF_LDX|BPF_W|BPF_LEN:
|
case BPF_LDX|BPF_W|BPF_LEN:
|
X = len;
|
X = len;
|
continue;
|
continue;
|
|
|
case BPF_LD|BPF_W|BPF_IND:
|
case BPF_LD|BPF_W|BPF_IND:
|
k = X + fentry->k;
|
k = X + fentry->k;
|
goto load_w;
|
goto load_w;
|
|
|
case BPF_LD|BPF_H|BPF_IND:
|
case BPF_LD|BPF_H|BPF_IND:
|
k = X + fentry->k;
|
k = X + fentry->k;
|
goto load_h;
|
goto load_h;
|
|
|
case BPF_LD|BPF_B|BPF_IND:
|
case BPF_LD|BPF_B|BPF_IND:
|
k = X + fentry->k;
|
k = X + fentry->k;
|
goto load_b;
|
goto load_b;
|
|
|
case BPF_LDX|BPF_B|BPF_MSH:
|
case BPF_LDX|BPF_B|BPF_MSH:
|
if(fentry->k >= len)
|
if(fentry->k >= len)
|
return (0);
|
return (0);
|
X = (data[fentry->k] & 0xf) << 2;
|
X = (data[fentry->k] & 0xf) << 2;
|
continue;
|
continue;
|
|
|
case BPF_LD|BPF_IMM:
|
case BPF_LD|BPF_IMM:
|
A = fentry->k;
|
A = fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_LDX|BPF_IMM:
|
case BPF_LDX|BPF_IMM:
|
X = fentry->k;
|
X = fentry->k;
|
continue;
|
continue;
|
|
|
case BPF_LD|BPF_MEM:
|
case BPF_LD|BPF_MEM:
|
A = mem[fentry->k];
|
A = mem[fentry->k];
|
continue;
|
continue;
|
|
|
case BPF_LDX|BPF_MEM:
|
case BPF_LDX|BPF_MEM:
|
X = mem[fentry->k];
|
X = mem[fentry->k];
|
continue;
|
continue;
|
|
|
case BPF_MISC|BPF_TAX:
|
case BPF_MISC|BPF_TAX:
|
X = A;
|
X = A;
|
continue;
|
continue;
|
|
|
case BPF_MISC|BPF_TXA:
|
case BPF_MISC|BPF_TXA:
|
A = X;
|
A = X;
|
continue;
|
continue;
|
|
|
case BPF_RET|BPF_K:
|
case BPF_RET|BPF_K:
|
return ((unsigned int)fentry->k);
|
return ((unsigned int)fentry->k);
|
|
|
case BPF_RET|BPF_A:
|
case BPF_RET|BPF_A:
|
return ((unsigned int)A);
|
return ((unsigned int)A);
|
|
|
case BPF_ST:
|
case BPF_ST:
|
mem[fentry->k] = A;
|
mem[fentry->k] = A;
|
continue;
|
continue;
|
|
|
case BPF_STX:
|
case BPF_STX:
|
mem[fentry->k] = X;
|
mem[fentry->k] = X;
|
continue;
|
continue;
|
|
|
default:
|
default:
|
/* Invalid instruction counts as RET */
|
/* Invalid instruction counts as RET */
|
return (0);
|
return (0);
|
}
|
}
|
|
|
/* Handle ancillary data, which are impossible
|
/* Handle ancillary data, which are impossible
|
(or very difficult) to get parsing packet contents.
|
(or very difficult) to get parsing packet contents.
|
*/
|
*/
|
switch (k-SKF_AD_OFF) {
|
switch (k-SKF_AD_OFF) {
|
case SKF_AD_PROTOCOL:
|
case SKF_AD_PROTOCOL:
|
A = htons(skb->protocol);
|
A = htons(skb->protocol);
|
continue;
|
continue;
|
case SKF_AD_PKTTYPE:
|
case SKF_AD_PKTTYPE:
|
A = skb->pkt_type;
|
A = skb->pkt_type;
|
continue;
|
continue;
|
case SKF_AD_IFINDEX:
|
case SKF_AD_IFINDEX:
|
A = skb->dev->ifindex;
|
A = skb->dev->ifindex;
|
continue;
|
continue;
|
default:
|
default:
|
return 0;
|
return 0;
|
}
|
}
|
}
|
}
|
|
|
return (0);
|
return (0);
|
}
|
}
|
|
|
/**
|
/**
|
* sk_chk_filter - verify socket filter code
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* sk_chk_filter - verify socket filter code
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* @filter: filter to verify
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* @filter: filter to verify
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* @flen: length of filter
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* @flen: length of filter
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*
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*
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* Check the user's filter code. If we let some ugly
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* Check the user's filter code. If we let some ugly
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* filter code slip through kaboom! The filter must contain
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* filter code slip through kaboom! The filter must contain
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* no references or jumps that are out of range, no illegal instructions
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* no references or jumps that are out of range, no illegal instructions
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* and no backward jumps. It must end with a RET instruction
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* and no backward jumps. It must end with a RET instruction
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*
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*
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* Returns 0 if the rule set is legal or a negative errno code if not.
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* Returns 0 if the rule set is legal or a negative errno code if not.
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*/
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*/
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int sk_chk_filter(struct sock_filter *filter, int flen)
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int sk_chk_filter(struct sock_filter *filter, int flen)
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{
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{
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struct sock_filter *ftest;
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struct sock_filter *ftest;
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int pc;
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int pc;
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|
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if ((unsigned int) flen >= (~0U / sizeof(struct sock_filter)))
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if ((unsigned int) flen >= (~0U / sizeof(struct sock_filter)))
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return -EINVAL;
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return -EINVAL;
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|
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/*
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/*
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* Check the filter code now.
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* Check the filter code now.
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*/
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*/
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for(pc = 0; pc < flen; pc++)
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for(pc = 0; pc < flen; pc++)
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{
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{
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/*
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/*
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* All jumps are forward as they are not signed
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* All jumps are forward as they are not signed
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*/
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*/
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|
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ftest = &filter[pc];
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ftest = &filter[pc];
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if(BPF_CLASS(ftest->code) == BPF_JMP)
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if(BPF_CLASS(ftest->code) == BPF_JMP)
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{
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{
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/*
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/*
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* But they mustn't jump off the end.
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* But they mustn't jump off the end.
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*/
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*/
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if(BPF_OP(ftest->code) == BPF_JA)
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if(BPF_OP(ftest->code) == BPF_JA)
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{
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{
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/* Note, the large ftest->k might cause
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/* Note, the large ftest->k might cause
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loops. Compare this with conditional
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loops. Compare this with conditional
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jumps below, where offsets are limited. --ANK (981016)
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jumps below, where offsets are limited. --ANK (981016)
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*/
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*/
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if (ftest->k >= (unsigned)(flen-pc-1))
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if (ftest->k >= (unsigned)(flen-pc-1))
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return -EINVAL;
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return -EINVAL;
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}
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}
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else
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else
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{
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{
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/*
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/*
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* For conditionals both must be safe
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* For conditionals both must be safe
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*/
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*/
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if(pc + ftest->jt +1 >= flen || pc + ftest->jf +1 >= flen)
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if(pc + ftest->jt +1 >= flen || pc + ftest->jf +1 >= flen)
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return -EINVAL;
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return -EINVAL;
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}
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}
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}
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}
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/*
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/*
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* Check that memory operations use valid addresses.
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* Check that memory operations use valid addresses.
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*/
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*/
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if (ftest->k >= BPF_MEMWORDS)
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if (ftest->k >= BPF_MEMWORDS)
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{
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{
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/*
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/*
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* But it might not be a memory operation...
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* But it might not be a memory operation...
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*/
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*/
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switch (ftest->code) {
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switch (ftest->code) {
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case BPF_ST:
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case BPF_ST:
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case BPF_STX:
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case BPF_STX:
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case BPF_LD|BPF_MEM:
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case BPF_LD|BPF_MEM:
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case BPF_LDX|BPF_MEM:
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case BPF_LDX|BPF_MEM:
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return -EINVAL;
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return -EINVAL;
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}
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}
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}
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}
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}
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}
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|
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/*
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/*
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* The program must end with a return. We don't care where they
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* The program must end with a return. We don't care where they
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* jumped within the script (its always forwards) but in the
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* jumped within the script (its always forwards) but in the
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* end they _will_ hit this.
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* end they _will_ hit this.
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*/
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*/
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|
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return (BPF_CLASS(filter[flen - 1].code) == BPF_RET)?0:-EINVAL;
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return (BPF_CLASS(filter[flen - 1].code) == BPF_RET)?0:-EINVAL;
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}
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}
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/**
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/**
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* sk_attach_filter - attach a socket filter
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* sk_attach_filter - attach a socket filter
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* @fprog: the filter program
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* @fprog: the filter program
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* @sk: the socket to use
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* @sk: the socket to use
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*
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*
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* Attach the user's filter code. We first run some sanity checks on
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* Attach the user's filter code. We first run some sanity checks on
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* it to make sure it does not explode on us later. If an error
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* it to make sure it does not explode on us later. If an error
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* occurs or there is insufficient memory for the filter a negative
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* occurs or there is insufficient memory for the filter a negative
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* errno code is returned. On success the return is zero.
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* errno code is returned. On success the return is zero.
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*/
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*/
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|
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int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
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int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
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{
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{
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struct sk_filter *fp;
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struct sk_filter *fp;
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unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
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unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
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int err;
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int err;
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|
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/* Make sure new filter is there and in the right amounts. */
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/* Make sure new filter is there and in the right amounts. */
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if (fprog->filter == NULL || fprog->len > BPF_MAXINSNS)
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if (fprog->filter == NULL || fprog->len > BPF_MAXINSNS)
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return (-EINVAL);
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return (-EINVAL);
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|
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fp = (struct sk_filter *)sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
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fp = (struct sk_filter *)sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
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if(fp == NULL)
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if(fp == NULL)
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return (-ENOMEM);
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return (-ENOMEM);
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|
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if (copy_from_user(fp->insns, fprog->filter, fsize)) {
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if (copy_from_user(fp->insns, fprog->filter, fsize)) {
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sock_kfree_s(sk, fp, fsize+sizeof(*fp));
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sock_kfree_s(sk, fp, fsize+sizeof(*fp));
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return -EFAULT;
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return -EFAULT;
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}
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}
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|
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atomic_set(&fp->refcnt, 1);
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atomic_set(&fp->refcnt, 1);
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fp->len = fprog->len;
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fp->len = fprog->len;
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|
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if ((err = sk_chk_filter(fp->insns, fp->len))==0) {
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if ((err = sk_chk_filter(fp->insns, fp->len))==0) {
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struct sk_filter *old_fp;
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struct sk_filter *old_fp;
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|
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spin_lock_bh(&sk->lock.slock);
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spin_lock_bh(&sk->lock.slock);
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old_fp = sk->filter;
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old_fp = sk->filter;
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sk->filter = fp;
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sk->filter = fp;
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spin_unlock_bh(&sk->lock.slock);
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spin_unlock_bh(&sk->lock.slock);
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fp = old_fp;
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fp = old_fp;
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}
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}
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|
|
if (fp)
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if (fp)
|
sk_filter_release(sk, fp);
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sk_filter_release(sk, fp);
|
|
|
return (err);
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return (err);
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}
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}
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#endif /* CONFIG_FILTER */
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#endif /* CONFIG_FILTER */
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