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author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-11-27 10:24:11 +0900 |
---|---|---|
committer | Paolo Abeni <pabeni@redhat.com> | 2022-12-01 10:32:20 +0100 |
commit | b3abe42e94900bdd045c472f9c9be620ba5ce553 (patch) | |
tree | 8c65c8bfdcdbf0c9ea045d8504dbb8da4147a0c8 /net | |
parent | d68d7d204afdc5e8e8f3e038e2ee048b5498ded3 (diff) | |
download | linux-stable-b3abe42e94900bdd045c472f9c9be620ba5ce553.tar.gz linux-stable-b3abe42e94900bdd045c472f9c9be620ba5ce553.tar.bz2 linux-stable-b3abe42e94900bdd045c472f9c9be620ba5ce553.zip |
af_unix: Get user_ns from in_skb in unix_diag_get_exact().
Wei Chen reported a NULL deref in sk_user_ns() [0][1], and Paolo diagnosed
the root cause: in unix_diag_get_exact(), the newly allocated skb does not
have sk. [2]
We must get the user_ns from the NETLINK_CB(in_skb).sk and pass it to
sk_diag_fill().
[0]:
BUG: kernel NULL pointer dereference, address: 0000000000000270
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 12bbce067 P4D 12bbce067 PUD 12bc40067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 27942 Comm: syz-executor.0 Not tainted 6.1.0-rc5-next-20221118 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
RIP: 0010:sk_user_ns include/net/sock.h:920 [inline]
RIP: 0010:sk_diag_dump_uid net/unix/diag.c:119 [inline]
RIP: 0010:sk_diag_fill+0x77d/0x890 net/unix/diag.c:170
Code: 89 ef e8 66 d4 2d fd c7 44 24 40 00 00 00 00 49 8d 7c 24 18 e8
54 d7 2d fd 49 8b 5c 24 18 48 8d bb 70 02 00 00 e8 43 d7 2d fd <48> 8b
9b 70 02 00 00 48 8d 7b 10 e8 33 d7 2d fd 48 8b 5b 10 48 8d
RSP: 0018:ffffc90000d67968 EFLAGS: 00010246
RAX: ffff88812badaa48 RBX: 0000000000000000 RCX: ffffffff840d481d
RDX: 0000000000000465 RSI: 0000000000000000 RDI: 0000000000000270
RBP: ffffc90000d679a8 R08: 0000000000000277 R09: 0000000000000000
R10: 0001ffffffffffff R11: 0001c90000d679a8 R12: ffff88812ac03800
R13: ffff88812c87c400 R14: ffff88812ae42210 R15: ffff888103026940
FS: 00007f08b4e6f700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000270 CR3: 000000012c58b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
unix_diag_get_exact net/unix/diag.c:285 [inline]
unix_diag_handler_dump+0x3f9/0x500 net/unix/diag.c:317
__sock_diag_cmd net/core/sock_diag.c:235 [inline]
sock_diag_rcv_msg+0x237/0x250 net/core/sock_diag.c:266
netlink_rcv_skb+0x13e/0x250 net/netlink/af_netlink.c:2564
sock_diag_rcv+0x24/0x40 net/core/sock_diag.c:277
netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
netlink_unicast+0x5e9/0x6b0 net/netlink/af_netlink.c:1356
netlink_sendmsg+0x739/0x860 net/netlink/af_netlink.c:1932
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
____sys_sendmsg+0x38f/0x500 net/socket.c:2476
___sys_sendmsg net/socket.c:2530 [inline]
__sys_sendmsg+0x197/0x230 net/socket.c:2559
__do_sys_sendmsg net/socket.c:2568 [inline]
__se_sys_sendmsg net/socket.c:2566 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2566
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x4697f9
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:00007f08b4e6ec48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000077bf80 RCX: 00000000004697f9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000004d29e9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000077bf80
R13: 0000000000000000 R14: 000000000077bf80 R15: 00007ffdb36bc6c0
</TASK>
Modules linked in:
CR2: 0000000000000270
[1]: https://lore.kernel.org/netdev/CAO4mrfdvyjFpokhNsiwZiP-wpdSD0AStcJwfKcKQdAALQ9_2Qw@mail.gmail.com/
[2]: https://lore.kernel.org/netdev/e04315e7c90d9a75613f3993c2baf2d344eef7eb.camel@redhat.com/
Fixes: cae9910e7344 ("net: Add UNIX_DIAG_UID to Netlink UNIX socket diagnostics.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: Wei Chen <harperchen1110@gmail.com>
Diagnosed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
-rw-r--r-- | net/unix/diag.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/net/unix/diag.c b/net/unix/diag.c index 105f522a89fe..616b55c5b890 100644 --- a/net/unix/diag.c +++ b/net/unix/diag.c @@ -114,14 +114,16 @@ static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb) return nla_put(nlskb, UNIX_DIAG_RQLEN, sizeof(rql), &rql); } -static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb) +static int sk_diag_dump_uid(struct sock *sk, struct sk_buff *nlskb, + struct user_namespace *user_ns) { - uid_t uid = from_kuid_munged(sk_user_ns(nlskb->sk), sock_i_uid(sk)); + uid_t uid = from_kuid_munged(user_ns, sock_i_uid(sk)); return nla_put(nlskb, UNIX_DIAG_UID, sizeof(uid_t), &uid); } static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req, - u32 portid, u32 seq, u32 flags, int sk_ino) + struct user_namespace *user_ns, + u32 portid, u32 seq, u32 flags, int sk_ino) { struct nlmsghdr *nlh; struct unix_diag_msg *rep; @@ -167,7 +169,7 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_r goto out_nlmsg_trim; if ((req->udiag_show & UDIAG_SHOW_UID) && - sk_diag_dump_uid(sk, skb)) + sk_diag_dump_uid(sk, skb, user_ns)) goto out_nlmsg_trim; nlmsg_end(skb, nlh); @@ -179,7 +181,8 @@ out_nlmsg_trim: } static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req, - u32 portid, u32 seq, u32 flags) + struct user_namespace *user_ns, + u32 portid, u32 seq, u32 flags) { int sk_ino; @@ -190,7 +193,7 @@ static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_r if (!sk_ino) return 0; - return sk_diag_fill(sk, skb, req, portid, seq, flags, sk_ino); + return sk_diag_fill(sk, skb, req, user_ns, portid, seq, flags, sk_ino); } static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) @@ -214,7 +217,7 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) goto next; if (!(req->udiag_states & (1 << sk->sk_state))) goto next; - if (sk_diag_dump(sk, skb, req, + if (sk_diag_dump(sk, skb, req, sk_user_ns(skb->sk), NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0) { @@ -282,7 +285,8 @@ again: if (!rep) goto out; - err = sk_diag_fill(sk, rep, req, NETLINK_CB(in_skb).portid, + err = sk_diag_fill(sk, rep, req, sk_user_ns(NETLINK_CB(in_skb).sk), + NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, 0, req->udiag_ino); if (err < 0) { nlmsg_free(rep); |