From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 0a78cf7264d29abeca098eae0b188a10aabc8a32 ]
Dae R. Jeong reported a NULL deref in raw_get_next() [0].
It seems that the repro was running these sequences in parallel so that one thread was iterating on a socket that was being freed in another netns.
unshare(0x40060200) r0 = syz_open_procfs(0x0, &(0x7f0000002080)='net/raw\x00') socket$inet_icmp_raw(0x2, 0x3, 0x1) pread64(r0, &(0x7f0000000000)=""/10, 0xa, 0x10000000007f)
After commit 0daf07e52709 ("raw: convert raw sockets to RCU"), we use RCU and hlist_nulls_for_each_entry() to iterate over SOCK_RAW sockets. However, we should use spinlock for slow paths to avoid the NULL deref.
Also, SOCK_RAW does not use SLAB_TYPESAFE_BY_RCU, and the slab object is not reused during iteration in the grace period. In fact, the lockless readers do not check the nulls marker with get_nulls_value(). So, SOCK_RAW should use hlist instead of hlist_nulls.
Instead of adding an unnecessary barrier by sk_nulls_for_each_rcu(), let's convert hlist_nulls to hlist and use sk_for_each_rcu() for fast paths and sk_for_each() and spinlock for /proc/net/raw.
[0]: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] CPU: 2 PID: 20952 Comm: syz-executor.0 Not tainted 6.2.0-g048ec869bafd-dirty #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:read_pnet include/net/net_namespace.h:383 [inline] RIP: 0010:sock_net include/net/sock.h:649 [inline] RIP: 0010:raw_get_next net/ipv4/raw.c:974 [inline] RIP: 0010:raw_get_idx net/ipv4/raw.c:986 [inline] RIP: 0010:raw_seq_start+0x431/0x800 net/ipv4/raw.c:995 Code: ef e8 33 3d 94 f7 49 8b 6d 00 4c 89 ef e8 b7 65 5f f7 49 89 ed 49 83 c5 98 0f 84 9a 00 00 00 48 83 c5 c8 48 89 e8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 ef e8 00 3d 94 f7 4c 8b 7d 00 48 89 ef RSP: 0018:ffffc9001154f9b0 EFLAGS: 00010206 RAX: 0000000000000005 RBX: 1ffff1100302c8fd RCX: 0000000000000000 RDX: 0000000000000028 RSI: ffffc9001154f988 RDI: ffffc9000f77a338 RBP: 0000000000000029 R08: ffffffff8a50ffb4 R09: fffffbfff24b6bd9 R10: fffffbfff24b6bd9 R11: 0000000000000000 R12: ffff88801db73b78 R13: fffffffffffffff9 R14: dffffc0000000000 R15: 0000000000000030 FS: 00007f843ae8e700(0000) GS:ffff888063700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055bb9614b35f CR3: 000000003c672000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> seq_read_iter+0x4c6/0x10f0 fs/seq_file.c:225 seq_read+0x224/0x320 fs/seq_file.c:162 pde_read fs/proc/inode.c:316 [inline] proc_reg_read+0x23f/0x330 fs/proc/inode.c:328 vfs_read+0x31e/0xd30 fs/read_write.c:468 ksys_pread64 fs/read_write.c:665 [inline] __do_sys_pread64 fs/read_write.c:675 [inline] __se_sys_pread64 fs/read_write.c:672 [inline] __x64_sys_pread64+0x1e9/0x280 fs/read_write.c:672 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x478d29 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f843ae8dbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000011 RAX: ffffffffffffffda RBX: 0000000000791408 RCX: 0000000000478d29 RDX: 000000000000000a RSI: 0000000020000000 RDI: 0000000000000003 RBP: 00000000f477909a R08: 0000000000000000 R09: 0000000000000000 R10: 000010000000007f R11: 0000000000000246 R12: 0000000000791740 R13: 0000000000791414 R14: 0000000000791408 R15: 00007ffc2eb48a50 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:read_pnet include/net/net_namespace.h:383 [inline] RIP: 0010:sock_net include/net/sock.h:649 [inline] RIP: 0010:raw_get_next net/ipv4/raw.c:974 [inline] RIP: 0010:raw_get_idx net/ipv4/raw.c:986 [inline] RIP: 0010:raw_seq_start+0x431/0x800 net/ipv4/raw.c:995 Code: ef e8 33 3d 94 f7 49 8b 6d 00 4c 89 ef e8 b7 65 5f f7 49 89 ed 49 83 c5 98 0f 84 9a 00 00 00 48 83 c5 c8 48 89 e8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 ef e8 00 3d 94 f7 4c 8b 7d 00 48 89 ef RSP: 0018:ffffc9001154f9b0 EFLAGS: 00010206 RAX: 0000000000000005 RBX: 1ffff1100302c8fd RCX: 0000000000000000 RDX: 0000000000000028 RSI: ffffc9001154f988 RDI: ffffc9000f77a338 RBP: 0000000000000029 R08: ffffffff8a50ffb4 R09: fffffbfff24b6bd9 R10: fffffbfff24b6bd9 R11: 0000000000000000 R12: ffff88801db73b78 R13: fffffffffffffff9 R14: dffffc0000000000 R15: 0000000000000030 FS: 00007f843ae8e700(0000) GS:ffff888063700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f92ff166000 CR3: 000000003c672000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: 0daf07e52709 ("raw: convert raw sockets to RCU") Reported-by: syzbot syzkaller@googlegroups.com Reported-by: Dae R. Jeong threeearcat@gmail.com Link: https://lore.kernel.org/netdev/ZCA2mGV_cmq7lIfV@dragonet/ Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/raw.h | 4 ++-- net/ipv4/raw.c | 36 +++++++++++++++++++----------------- net/ipv4/raw_diag.c | 10 ++++------ net/ipv6/raw.c | 10 ++++------ 4 files changed, 29 insertions(+), 31 deletions(-)
diff --git a/include/net/raw.h b/include/net/raw.h index 2c004c20ed996..3af5289fdead9 100644 --- a/include/net/raw.h +++ b/include/net/raw.h @@ -37,7 +37,7 @@ int raw_rcv(struct sock *, struct sk_buff *); struct raw_hashinfo { spinlock_t lock;
- struct hlist_nulls_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned; + struct hlist_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned; };
static inline u32 raw_hashfunc(const struct net *net, u32 proto) @@ -51,7 +51,7 @@ static inline void raw_hashinfo_init(struct raw_hashinfo *hashinfo)
spin_lock_init(&hashinfo->lock); for (i = 0; i < RAW_HTABLE_SIZE; i++) - INIT_HLIST_NULLS_HEAD(&hashinfo->ht[i], i); + INIT_HLIST_HEAD(&hashinfo->ht[i]); }
#ifdef CONFIG_PROC_FS diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 2a53a0bf29232..af03aa8a8e513 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -91,12 +91,12 @@ EXPORT_SYMBOL_GPL(raw_v4_hashinfo); int raw_hash_sk(struct sock *sk) { struct raw_hashinfo *h = sk->sk_prot->h.raw_hash; - struct hlist_nulls_head *hlist; + struct hlist_head *hlist;
hlist = &h->ht[raw_hashfunc(sock_net(sk), inet_sk(sk)->inet_num)];
spin_lock(&h->lock); - __sk_nulls_add_node_rcu(sk, hlist); + sk_add_node_rcu(sk, hlist); sock_set_flag(sk, SOCK_RCU_FREE); spin_unlock(&h->lock); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); @@ -110,7 +110,7 @@ void raw_unhash_sk(struct sock *sk) struct raw_hashinfo *h = sk->sk_prot->h.raw_hash;
spin_lock(&h->lock); - if (__sk_nulls_del_node_init_rcu(sk)) + if (sk_del_node_init_rcu(sk)) sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); spin_unlock(&h->lock); } @@ -163,16 +163,15 @@ static int icmp_filter(const struct sock *sk, const struct sk_buff *skb) static int raw_v4_input(struct net *net, struct sk_buff *skb, const struct iphdr *iph, int hash) { - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; int sdif = inet_sdif(skb); + struct hlist_head *hlist; int dif = inet_iif(skb); int delivered = 0; struct sock *sk;
hlist = &raw_v4_hashinfo.ht[hash]; rcu_read_lock(); - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { if (!raw_v4_match(net, sk, iph->protocol, iph->saddr, iph->daddr, dif, sdif)) continue; @@ -264,10 +263,9 @@ static void raw_err(struct sock *sk, struct sk_buff *skb, u32 info) void raw_icmp_error(struct sk_buff *skb, int protocol, u32 info) { struct net *net = dev_net(skb->dev); - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; int dif = skb->dev->ifindex; int sdif = inet_sdif(skb); + struct hlist_head *hlist; const struct iphdr *iph; struct sock *sk; int hash; @@ -276,7 +274,7 @@ void raw_icmp_error(struct sk_buff *skb, int protocol, u32 info) hlist = &raw_v4_hashinfo.ht[hash];
rcu_read_lock(); - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { iph = (const struct iphdr *)skb->data; if (!raw_v4_match(net, sk, iph->protocol, iph->daddr, iph->saddr, dif, sdif)) @@ -948,14 +946,13 @@ static struct sock *raw_get_first(struct seq_file *seq, int bucket) { struct raw_hashinfo *h = pde_data(file_inode(seq->file)); struct raw_iter_state *state = raw_seq_private(seq); - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; + struct hlist_head *hlist; struct sock *sk;
for (state->bucket = bucket; state->bucket < RAW_HTABLE_SIZE; ++state->bucket) { hlist = &h->ht[state->bucket]; - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each(sk, hlist) { if (sock_net(sk) == seq_file_net(seq)) return sk; } @@ -968,7 +965,7 @@ static struct sock *raw_get_next(struct seq_file *seq, struct sock *sk) struct raw_iter_state *state = raw_seq_private(seq);
do { - sk = sk_nulls_next(sk); + sk = sk_next(sk); } while (sk && sock_net(sk) != seq_file_net(seq));
if (!sk) @@ -987,9 +984,12 @@ static struct sock *raw_get_idx(struct seq_file *seq, loff_t pos) }
void *raw_seq_start(struct seq_file *seq, loff_t *pos) - __acquires(RCU) + __acquires(&h->lock) { - rcu_read_lock(); + struct raw_hashinfo *h = pde_data(file_inode(seq->file)); + + spin_lock(&h->lock); + return *pos ? raw_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; } EXPORT_SYMBOL_GPL(raw_seq_start); @@ -1008,9 +1008,11 @@ void *raw_seq_next(struct seq_file *seq, void *v, loff_t *pos) EXPORT_SYMBOL_GPL(raw_seq_next);
void raw_seq_stop(struct seq_file *seq, void *v) - __releases(RCU) + __releases(&h->lock) { - rcu_read_unlock(); + struct raw_hashinfo *h = pde_data(file_inode(seq->file)); + + spin_unlock(&h->lock); } EXPORT_SYMBOL_GPL(raw_seq_stop);
diff --git a/net/ipv4/raw_diag.c b/net/ipv4/raw_diag.c index 999321834b94a..da3591a66a169 100644 --- a/net/ipv4/raw_diag.c +++ b/net/ipv4/raw_diag.c @@ -57,8 +57,7 @@ static bool raw_lookup(struct net *net, struct sock *sk, static struct sock *raw_sock_get(struct net *net, const struct inet_diag_req_v2 *r) { struct raw_hashinfo *hashinfo = raw_get_hashinfo(r); - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; + struct hlist_head *hlist; struct sock *sk; int slot;
@@ -68,7 +67,7 @@ static struct sock *raw_sock_get(struct net *net, const struct inet_diag_req_v2 rcu_read_lock(); for (slot = 0; slot < RAW_HTABLE_SIZE; slot++) { hlist = &hashinfo->ht[slot]; - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { if (raw_lookup(net, sk, r)) { /* * Grab it and keep until we fill @@ -142,9 +141,8 @@ static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, struct raw_hashinfo *hashinfo = raw_get_hashinfo(r); struct net *net = sock_net(skb->sk); struct inet_diag_dump_data *cb_data; - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; int num, s_num, slot, s_slot; + struct hlist_head *hlist; struct sock *sk = NULL; struct nlattr *bc;
@@ -161,7 +159,7 @@ static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, num = 0;
hlist = &hashinfo->ht[slot]; - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { struct inet_sock *inet = inet_sk(sk);
if (!net_eq(sock_net(sk), net)) diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 45b35b5f893c5..4fc511bdf176c 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -141,10 +141,9 @@ EXPORT_SYMBOL(rawv6_mh_filter_unregister); static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr) { struct net *net = dev_net(skb->dev); - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; const struct in6_addr *saddr; const struct in6_addr *daddr; + struct hlist_head *hlist; struct sock *sk; bool delivered = false; __u8 hash; @@ -155,7 +154,7 @@ static bool ipv6_raw_deliver(struct sk_buff *skb, int nexthdr) hash = raw_hashfunc(net, nexthdr); hlist = &raw_v6_hashinfo.ht[hash]; rcu_read_lock(); - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { int filtered;
if (!raw_v6_match(net, sk, nexthdr, daddr, saddr, @@ -333,15 +332,14 @@ void raw6_icmp_error(struct sk_buff *skb, int nexthdr, u8 type, u8 code, int inner_offset, __be32 info) { struct net *net = dev_net(skb->dev); - struct hlist_nulls_head *hlist; - struct hlist_nulls_node *hnode; + struct hlist_head *hlist; struct sock *sk; int hash;
hash = raw_hashfunc(net, nexthdr); hlist = &raw_v6_hashinfo.ht[hash]; rcu_read_lock(); - sk_nulls_for_each(sk, hnode, hlist) { + sk_for_each_rcu(sk, hlist) { /* Note: ipv6_hdr(skb) != skb->data */ const struct ipv6hdr *ip6h = (const struct ipv6hdr *)skb->data;