net: fix unsafe set_memory_rw from softirq
on x86 system with net.core.bpf_jit_enable = 1 sudo tcpdump -i eth1 'tcp port 22' causes the warning: [ 56.766097] Possible unsafe locking scenario: [ 56.766097] [ 56.780146] CPU0 [ 56.786807] ---- [ 56.793188] lock(&(&vb->lock)->rlock); [ 56.799593] <Interrupt> [ 56.805889] lock(&(&vb->lock)->rlock); [ 56.812266] [ 56.812266] *** DEADLOCK *** [ 56.812266] [ 56.830670] 1 lock held by ksoftirqd/1/13: [ 56.836838] #0: (rcu_read_lock){.+.+..}, at: [<ffffffff8118f44c>] vm_unmap_aliases+0x8c/0x380 [ 56.849757] [ 56.849757] stack backtrace: [ 56.862194] CPU: 1 PID: 13 Comm: ksoftirqd/1 Not tainted 3.12.0-rc3+ #45 [ 56.868721] Hardware name: System manufacturer System Product Name/P8Z77 WS, BIOS 3007 07/26/2012 [ 56.882004] ffffffff821944c0 ffff88080bbdb8c8 ffffffff8175a145 0000000000000007 [ 56.895630] ffff88080bbd5f40 ffff88080bbdb928 ffffffff81755b14 0000000000000001 [ 56.909313] ffff880800000001 ffff880800000000 ffffffff8101178f 0000000000000001 [ 56.923006] Call Trace: [ 56.929532] [<ffffffff8175a145>] dump_stack+0x55/0x76 [ 56.936067] [<ffffffff81755b14>] print_usage_bug+0x1f7/0x208 [ 56.942445] [<ffffffff8101178f>] ? save_stack_trace+0x2f/0x50 [ 56.948932] [<ffffffff810cc0a0>] ? check_usage_backwards+0x150/0x150 [ 56.955470] [<ffffffff810ccb52>] mark_lock+0x282/0x2c0 [ 56.961945] [<ffffffff810ccfed>] __lock_acquire+0x45d/0x1d50 [ 56.968474] [<ffffffff810cce6e>] ? __lock_acquire+0x2de/0x1d50 [ 56.975140] [<ffffffff81393bf5>] ? cpumask_next_and+0x55/0x90 [ 56.981942] [<ffffffff810cef72>] lock_acquire+0x92/0x1d0 [ 56.988745] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380 [ 56.995619] [<ffffffff817628f1>] _raw_spin_lock+0x41/0x50 [ 57.002493] [<ffffffff8118f52a>] ? vm_unmap_aliases+0x16a/0x380 [ 57.009447] [<ffffffff8118f52a>] vm_unmap_aliases+0x16a/0x380 [ 57.016477] [<ffffffff8118f44c>] ? vm_unmap_aliases+0x8c/0x380 [ 57.023607] [<ffffffff810436b0>] change_page_attr_set_clr+0xc0/0x460 [ 57.030818] [<ffffffff810cfb8d>] ? trace_hardirqs_on+0xd/0x10 [ 57.037896] [<ffffffff811a8330>] ? kmem_cache_free+0xb0/0x2b0 [ 57.044789] [<ffffffff811b59c3>] ? free_object_rcu+0x93/0xa0 [ 57.051720] [<ffffffff81043d9f>] set_memory_rw+0x2f/0x40 [ 57.058727] [<ffffffff8104e17c>] bpf_jit_free+0x2c/0x40 [ 57.065577] [<ffffffff81642cba>] sk_filter_release_rcu+0x1a/0x30 [ 57.072338] [<ffffffff811108e2>] rcu_process_callbacks+0x202/0x7c0 [ 57.078962] [<ffffffff81057f17>] __do_softirq+0xf7/0x3f0 [ 57.085373] [<ffffffff81058245>] run_ksoftirqd+0x35/0x70 cannot reuse jited filter memory, since it's readonly, so use original bpf insns memory to hold work_struct defer kfree of sk_filter until jit completed freeing tested on x86_64 and i386 Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
582442d6d5
commit
d45ed4a4e3
8 changed files with 36 additions and 18 deletions
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@ -930,4 +930,5 @@ void bpf_jit_free(struct sk_filter *fp)
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{
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if (fp->bpf_func != sk_run_filter)
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module_free(NULL, fp->bpf_func);
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kfree(fp);
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}
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@ -691,4 +691,5 @@ void bpf_jit_free(struct sk_filter *fp)
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{
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if (fp->bpf_func != sk_run_filter)
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module_free(NULL, fp->bpf_func);
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kfree(fp);
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}
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@ -881,7 +881,9 @@ void bpf_jit_free(struct sk_filter *fp)
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struct bpf_binary_header *header = (void *)addr;
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if (fp->bpf_func == sk_run_filter)
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return;
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goto free_filter;
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set_memory_rw(addr, header->pages);
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module_free(NULL, header);
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free_filter:
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kfree(fp);
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}
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@ -808,4 +808,5 @@ void bpf_jit_free(struct sk_filter *fp)
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{
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if (fp->bpf_func != sk_run_filter)
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module_free(NULL, fp->bpf_func);
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kfree(fp);
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}
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@ -772,13 +772,21 @@ cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
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return;
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}
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static void bpf_jit_free_deferred(struct work_struct *work)
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{
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struct sk_filter *fp = container_of(work, struct sk_filter, work);
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unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
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struct bpf_binary_header *header = (void *)addr;
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set_memory_rw(addr, header->pages);
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module_free(NULL, header);
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kfree(fp);
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}
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void bpf_jit_free(struct sk_filter *fp)
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{
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if (fp->bpf_func != sk_run_filter) {
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unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
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struct bpf_binary_header *header = (void *)addr;
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set_memory_rw(addr, header->pages);
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module_free(NULL, header);
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INIT_WORK(&fp->work, bpf_jit_free_deferred);
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schedule_work(&fp->work);
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}
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}
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@ -6,6 +6,7 @@
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#include <linux/atomic.h>
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#include <linux/compat.h>
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#include <linux/workqueue.h>
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#include <uapi/linux/filter.h>
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#ifdef CONFIG_COMPAT
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@ -25,15 +26,19 @@ struct sk_filter
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{
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atomic_t refcnt;
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unsigned int len; /* Number of filter blocks */
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struct rcu_head rcu;
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unsigned int (*bpf_func)(const struct sk_buff *skb,
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const struct sock_filter *filter);
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struct rcu_head rcu;
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struct sock_filter insns[0];
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union {
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struct sock_filter insns[0];
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struct work_struct work;
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};
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};
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static inline unsigned int sk_filter_len(const struct sk_filter *fp)
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static inline unsigned int sk_filter_size(unsigned int proglen)
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{
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return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
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return max(sizeof(struct sk_filter),
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offsetof(struct sk_filter, insns[proglen]));
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}
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extern int sk_filter(struct sock *sk, struct sk_buff *skb);
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@ -67,11 +72,13 @@ static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
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}
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#define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
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#else
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#include <linux/slab.h>
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static inline void bpf_jit_compile(struct sk_filter *fp)
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{
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}
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static inline void bpf_jit_free(struct sk_filter *fp)
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{
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kfree(fp);
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}
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#define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
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#endif
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@ -1630,16 +1630,14 @@ static inline void sk_filter_release(struct sk_filter *fp)
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static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
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{
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unsigned int size = sk_filter_len(fp);
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atomic_sub(size, &sk->sk_omem_alloc);
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atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc);
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sk_filter_release(fp);
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}
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static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
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{
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atomic_inc(&fp->refcnt);
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atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
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atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc);
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}
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/*
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@ -644,7 +644,6 @@ void sk_filter_release_rcu(struct rcu_head *rcu)
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struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
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bpf_jit_free(fp);
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kfree(fp);
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}
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EXPORT_SYMBOL(sk_filter_release_rcu);
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@ -683,7 +682,7 @@ int sk_unattached_filter_create(struct sk_filter **pfp,
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if (fprog->filter == NULL)
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return -EINVAL;
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fp = kmalloc(fsize + sizeof(*fp), GFP_KERNEL);
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fp = kmalloc(sk_filter_size(fprog->len), GFP_KERNEL);
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if (!fp)
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return -ENOMEM;
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memcpy(fp->insns, fprog->filter, fsize);
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@ -723,6 +722,7 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
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{
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struct sk_filter *fp, *old_fp;
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unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
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unsigned int sk_fsize = sk_filter_size(fprog->len);
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int err;
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if (sock_flag(sk, SOCK_FILTER_LOCKED))
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@ -732,11 +732,11 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
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if (fprog->filter == NULL)
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return -EINVAL;
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fp = sock_kmalloc(sk, fsize+sizeof(*fp), GFP_KERNEL);
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fp = sock_kmalloc(sk, sk_fsize, GFP_KERNEL);
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if (!fp)
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return -ENOMEM;
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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, sk_fsize);
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return -EFAULT;
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}
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