| From ba0e3427b03c3d1550239779eca5c1c5a53a2152 Mon Sep 17 00:00:00 2001 |
| From: "Eric W. Biederman" <ebiederm@xmission.com> |
| Date: Sat, 2 Mar 2013 19:14:03 -0800 |
| Subject: userns: Stop oopsing in key_change_session_keyring |
| |
| From: "Eric W. Biederman" <ebiederm@xmission.com> |
| |
| commit ba0e3427b03c3d1550239779eca5c1c5a53a2152 upstream. |
| |
| Dave Jones <davej@redhat.com> writes: |
| > Just hit this on Linus' current tree. |
| > |
| > [ 89.621770] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 |
| > [ 89.623111] IP: [<ffffffff810784b0>] commit_creds+0x250/0x2f0 |
| > [ 89.624062] PGD 122bfd067 PUD 122bfe067 PMD 0 |
| > [ 89.624901] Oops: 0000 [#1] PREEMPT SMP |
| > [ 89.625678] Modules linked in: caif_socket caif netrom bridge hidp 8021q garp stp mrp rose llc2 af_rxrpc phonet af_key binfmt_misc bnep l2tp_ppp can_bcm l2tp_core pppoe pppox can_raw scsi_transport_iscsi ppp_generic slhc nfnetlink can ipt_ULOG ax25 decnet irda nfc rds x25 crc_ccitt appletalk atm ipx p8023 psnap p8022 llc lockd sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack nf_conntrack ip6table_filter ip6_tables btusb bluetooth snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_pcm vhost_net snd_page_alloc snd_timer tun macvtap usb_debug snd rfkill microcode macvlan edac_core pcspkr serio_raw kvm_amd soundcore kvm r8169 mii |
| > [ 89.637846] CPU 2 |
| > [ 89.638175] Pid: 782, comm: trinity-main Not tainted 3.8.0+ #63 Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H |
| > [ 89.639850] RIP: 0010:[<ffffffff810784b0>] [<ffffffff810784b0>] commit_creds+0x250/0x2f0 |
| > [ 89.641161] RSP: 0018:ffff880115657eb8 EFLAGS: 00010207 |
| > [ 89.641984] RAX: 00000000000003e8 RBX: ffff88012688b000 RCX: 0000000000000000 |
| > [ 89.643069] RDX: 0000000000000000 RSI: ffffffff81c32960 RDI: ffff880105839600 |
| > [ 89.644167] RBP: ffff880115657ed8 R08: 0000000000000000 R09: 0000000000000000 |
| > [ 89.645254] R10: 0000000000000001 R11: 0000000000000246 R12: ffff880105839600 |
| > [ 89.646340] R13: ffff88011beea490 R14: ffff88011beea490 R15: 0000000000000000 |
| > [ 89.647431] FS: 00007f3ac063b740(0000) GS:ffff88012b200000(0000) knlGS:0000000000000000 |
| > [ 89.648660] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b |
| > [ 89.649548] CR2: 00000000000000c8 CR3: 0000000122bfc000 CR4: 00000000000007e0 |
| > [ 89.650635] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| > [ 89.651723] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 |
| > [ 89.652812] Process trinity-main (pid: 782, threadinfo ffff880115656000, task ffff88011beea490) |
| > [ 89.654128] Stack: |
| > [ 89.654433] 0000000000000000 ffff8801058396a0 ffff880105839600 ffff88011beeaa78 |
| > [ 89.655769] ffff880115657ef8 ffffffff812c7d9b ffffffff82079be0 0000000000000000 |
| > [ 89.657073] ffff880115657f28 ffffffff8106c665 0000000000000002 ffff880115657f58 |
| > [ 89.658399] Call Trace: |
| > [ 89.658822] [<ffffffff812c7d9b>] key_change_session_keyring+0xfb/0x140 |
| > [ 89.659845] [<ffffffff8106c665>] task_work_run+0xa5/0xd0 |
| > [ 89.660698] [<ffffffff81002911>] do_notify_resume+0x71/0xb0 |
| > [ 89.661581] [<ffffffff816c9a4a>] int_signal+0x12/0x17 |
| > [ 89.662385] Code: 24 90 00 00 00 48 8b b3 90 00 00 00 49 8b 4c 24 40 48 39 f2 75 08 e9 83 00 00 00 48 89 ca 48 81 fa 60 29 c3 81 0f 84 41 fe ff ff <48> 8b 8a c8 00 00 00 48 39 ce 75 e4 3b 82 d0 00 00 00 0f 84 4b |
| > [ 89.667778] RIP [<ffffffff810784b0>] commit_creds+0x250/0x2f0 |
| > [ 89.668733] RSP <ffff880115657eb8> |
| > [ 89.669301] CR2: 00000000000000c8 |
| > |
| > My fastest trinity induced oops yet! |
| > |
| > |
| > Appears to be.. |
| > |
| > if ((set_ns == subset_ns->parent) && |
| > 850: 48 8b 8a c8 00 00 00 mov 0xc8(%rdx),%rcx |
| > |
| > from the inlined cred_cap_issubset |
| |
| By historical accident we have been reading trying to set new->user_ns |
| from new->user_ns. Which is totally silly as new->user_ns is NULL (as |
| is every other field in new except session_keyring at that point). |
| |
| The intent is clearly to copy all of the fields from old to new so copy |
| old->user_ns into into new->user_ns. |
| |
| Reported-by: Dave Jones <davej@redhat.com> |
| Tested-by: Dave Jones <davej@redhat.com> |
| Acked-by: Serge Hallyn <serge.hallyn@canonical.com> |
| Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| security/keys/process_keys.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/security/keys/process_keys.c |
| +++ b/security/keys/process_keys.c |
| @@ -839,7 +839,7 @@ void key_change_session_keyring(struct c |
| new-> sgid = old-> sgid; |
| new->fsgid = old->fsgid; |
| new->user = get_uid(old->user); |
| - new->user_ns = get_user_ns(new->user_ns); |
| + new->user_ns = get_user_ns(old->user_ns); |
| new->group_info = get_group_info(old->group_info); |
| |
| new->securebits = old->securebits; |