676d23690f
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
86 lines
1.8 KiB
C
86 lines
1.8 KiB
C
/* net/atm/raw.c - Raw AAL0 and AAL5 transports */
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/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
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#include <linux/module.h>
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#include <linux/atmdev.h>
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#include <linux/capability.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include "common.h"
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#include "protocols.h"
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/*
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* SKB == NULL indicates that the link is being closed
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*/
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static void atm_push_raw(struct atm_vcc *vcc, struct sk_buff *skb)
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{
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if (skb) {
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struct sock *sk = sk_atm(vcc);
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skb_queue_tail(&sk->sk_receive_queue, skb);
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sk->sk_data_ready(sk);
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}
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}
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static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb)
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{
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struct sock *sk = sk_atm(vcc);
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pr_debug("(%d) %d -= %d\n",
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vcc->vci, sk_wmem_alloc_get(sk), skb->truesize);
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atomic_sub(skb->truesize, &sk->sk_wmem_alloc);
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dev_kfree_skb_any(skb);
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sk->sk_write_space(sk);
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}
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static int atm_send_aal0(struct atm_vcc *vcc, struct sk_buff *skb)
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{
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/*
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* Note that if vpi/vci are _ANY or _UNSPEC the below will
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* still work
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*/
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if (!capable(CAP_NET_ADMIN) &&
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(((u32 *)skb->data)[0] & (ATM_HDR_VPI_MASK | ATM_HDR_VCI_MASK)) !=
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((vcc->vpi << ATM_HDR_VPI_SHIFT) |
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(vcc->vci << ATM_HDR_VCI_SHIFT))) {
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kfree_skb(skb);
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return -EADDRNOTAVAIL;
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}
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return vcc->dev->ops->send(vcc, skb);
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}
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int atm_init_aal0(struct atm_vcc *vcc)
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{
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vcc->push = atm_push_raw;
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vcc->pop = atm_pop_raw;
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vcc->push_oam = NULL;
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vcc->send = atm_send_aal0;
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return 0;
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}
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int atm_init_aal34(struct atm_vcc *vcc)
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{
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vcc->push = atm_push_raw;
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vcc->pop = atm_pop_raw;
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vcc->push_oam = NULL;
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vcc->send = vcc->dev->ops->send;
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return 0;
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}
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int atm_init_aal5(struct atm_vcc *vcc)
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{
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vcc->push = atm_push_raw;
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vcc->pop = atm_pop_raw;
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vcc->push_oam = NULL;
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vcc->send = vcc->dev->ops->send;
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return 0;
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}
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EXPORT_SYMBOL(atm_init_aal5);
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