From patchwork Mon May 18 15:08:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 11555553 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 96E9E90 for ; Mon, 18 May 2020 15:09:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76291207C4 for ; Mon, 18 May 2020 15:09:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726998AbgERPJu (ORCPT ); Mon, 18 May 2020 11:09:50 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:45912 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726918AbgERPJu (ORCPT ); Mon, 18 May 2020 11:09:50 -0400 Received: from comp-core-i7-2640m-0182e6.redhat.com (ip-89-102-33-211.net.upcbroadband.cz [89.102.33.211]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by raptor.unsafe.ru (Postfix) with ESMTPSA id 2CA0720479; Mon, 18 May 2020 15:09:44 +0000 (UTC) From: Alexey Gladkov To: "Eric W. Biederman" Cc: LKML , Tetsuo Handa , syzbot , jmorris@namei.org, linux-next@vger.kernel.org, linux-security-module@vger.kernel.org, serge@hallyn.com, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com, linux-fsdevel Subject: [PATCH v3] proc: proc_pid_ns takes super_block as an argument Date: Mon, 18 May 2020 17:08:18 +0200 Message-Id: <20200518150818.2929164-1-gladkov.alexey@gmail.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <87lfltcbc4.fsf@x220.int.ebiederm.org> References: <87lfltcbc4.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.6.1 (raptor.unsafe.ru [5.9.43.93]); Mon, 18 May 2020 15:09:47 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: syzbot writes: > general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] > CPU: 0 PID: 6698 Comm: sshd Not tainted 5.7.0-rc5-next-20200515-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:tomoyo_get_local_path+0x450/0x800 security/tomoyo/realpath.c:165 > Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b4 03 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 7f 60 49 8d 7f 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 87 03 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b > RSP: 0018:ffffc900063d7450 EFLAGS: 00010206 > RAX: dffffc0000000000 RBX: ffff88809975c000 RCX: ffffffff8363deda > RDX: 0000000000000005 RSI: ffffffff8363dee8 RDI: 0000000000000028 > RBP: 1ffff92000c7ae8b R08: ffff8880a47644c0 R09: fffffbfff155a0a2 > R10: ffffffff8aad050f R11: fffffbfff155a0a1 R12: ffff88809df3cfea > R13: ffff88809df3c000 R14: 0000000000001a2a R15: 0000000000000000 > FS: 00007efe13ce28c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055e78cf578f5 CR3: 00000000987ed000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > tomoyo_realpath_from_path+0x393/0x620 security/tomoyo/realpath.c:282 > tomoyo_get_realpath security/tomoyo/file.c:151 [inline] > tomoyo_path_number_perm+0x1c2/0x4d0 security/tomoyo/file.c:723 > tomoyo_path_mknod+0x10d/0x190 security/tomoyo/tomoyo.c:246 > security_path_mknod+0x116/0x180 security/security.c:1072 > may_o_create fs/namei.c:2905 [inline] > lookup_open+0x5ae/0x1320 fs/namei.c:3046 > open_last_lookups fs/namei.c:3155 [inline] > path_openat+0x93c/0x27f0 fs/namei.c:3343 > do_filp_open+0x192/0x260 fs/namei.c:3373 > do_sys_openat2+0x585/0x7d0 fs/open.c:1179 > do_sys_open+0xc3/0x140 fs/open.c:1195 > do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 > entry_SYSCALL_64_after_hwframe+0x49/0xb3 > RIP: 0033:0x7efe11e4b6f0 > Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 19 30 2c 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 fe 9d 01 00 48 89 04 24 > RSP: 002b:00007ffc3d0894d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 > RAX: ffffffffffffffda RBX: 000055e78f0bc110 RCX: 00007efe11e4b6f0 > RDX: 00000000000001b6 RSI: 0000000000000241 RDI: 000055e78cf578f5 > RBP: 0000000000000004 R08: 0000000000000004 R09: 0000000000000001 > R10: 0000000000000240 R11: 0000000000000246 R12: 000055e78cf2851e > R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > ---[ end trace 0a58064de06d50f4 ]--- > RIP: 0010:tomoyo_get_local_path+0x450/0x800 security/tomoyo/realpath.c:165 > Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b4 03 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 7f 60 49 8d 7f 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 87 03 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b > RSP: 0018:ffffc900063d7450 EFLAGS: 00010206 > RAX: dffffc0000000000 RBX: ffff88809975c000 RCX: ffffffff8363deda > RDX: 0000000000000005 RSI: ffffffff8363dee8 RDI: 0000000000000028 > RBP: 1ffff92000c7ae8b R08: ffff8880a47644c0 R09: fffffbfff155a0a2 > R10: ffffffff8aad050f R11: fffffbfff155a0a1 R12: ffff88809df3cfea > R13: ffff88809df3c000 R14: 0000000000001a2a R15: 0000000000000000 > FS: 00007efe13ce28c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055dfe16c15f8 CR3: 00000000987ed000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 This is happening as part of creating a file or a device node. The dentry that is passed in most likely comes from d_alloc_parallel and does not have a d_inode. Before c59f415a7cb6, Tomoyo received pid_ns from proc's s_fs_info directly. Since proc_pid_ns() can only work with inode, using it in the tomoyo_get_local_path() was wrong. To avoid creating more functions for getting proc_ns would be more correct to change the argument type of the proc_pid_ns() function. In this case, Tomoyo can use the existing super_block to get pid_ns. Reported-by: syzbot+c1af344512918c61362c@syzkaller.appspotmail.com Fixes: c59f415a7cb6 ("Use proc_pid_ns() to get pid_namespace from the proc superblock") Signed-off-by: Alexey Gladkov --- fs/locks.c | 4 ++-- fs/proc/array.c | 2 +- fs/proc/base.c | 10 +++++----- fs/proc/self.c | 2 +- fs/proc/thread_self.c | 2 +- include/linux/proc_fs.h | 4 ++-- kernel/fork.c | 2 +- net/ipv6/ip6_flowlabel.c | 2 +- security/tomoyo/realpath.c | 2 +- 9 files changed, 15 insertions(+), 15 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 399c5dbb72c4..ab702d6efb55 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2823,7 +2823,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, { struct inode *inode = NULL; unsigned int fl_pid; - struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)); + struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb); fl_pid = locks_translate_pid(fl, proc_pidns); /* @@ -2901,7 +2901,7 @@ static int locks_show(struct seq_file *f, void *v) { struct locks_iterator *iter = f->private; struct file_lock *fl, *bfl; - struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)); + struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb); fl = hlist_entry(v, struct file_lock, fl_link); diff --git a/fs/proc/array.c b/fs/proc/array.c index 8e16f14bb05a..043311014db2 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -728,7 +728,7 @@ static int children_seq_show(struct seq_file *seq, void *v) { struct inode *inode = file_inode(seq->file); - seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode))); + seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode->i_sb))); return 0; } diff --git a/fs/proc/base.c b/fs/proc/base.c index 5a307b3bb2d1..30c9fceca0b7 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -754,7 +754,7 @@ static const struct inode_operations proc_def_inode_operations = { static int proc_single_show(struct seq_file *m, void *v) { struct inode *inode = m->private; - struct pid_namespace *ns = proc_pid_ns(inode); + struct pid_namespace *ns = proc_pid_ns(inode->i_sb); struct pid *pid = proc_pid(inode); struct task_struct *task; int ret; @@ -1423,7 +1423,7 @@ static const struct file_operations proc_fail_nth_operations = { static int sched_show(struct seq_file *m, void *v) { struct inode *inode = m->private; - struct pid_namespace *ns = proc_pid_ns(inode); + struct pid_namespace *ns = proc_pid_ns(inode->i_sb); struct task_struct *p; p = get_proc_task(inode); @@ -2466,7 +2466,7 @@ static int proc_timers_open(struct inode *inode, struct file *file) return -ENOMEM; tp->pid = proc_pid(inode); - tp->ns = proc_pid_ns(inode); + tp->ns = proc_pid_ns(inode->i_sb); return 0; } @@ -3377,7 +3377,7 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) { struct tgid_iter iter; struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb); - struct pid_namespace *ns = proc_pid_ns(file_inode(file)); + struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb); loff_t pos = ctx->pos; if (pos >= PID_MAX_LIMIT + TGID_OFFSET) @@ -3730,7 +3730,7 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx) /* f_version caches the tgid value that the last readdir call couldn't * return. lseek aka telldir automagically resets f_version to 0. */ - ns = proc_pid_ns(inode); + ns = proc_pid_ns(inode->i_sb); tid = (int)file->f_version; file->f_version = 0; for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns); diff --git a/fs/proc/self.c b/fs/proc/self.c index 309301ac0136..ca5158fa561c 100644 --- a/fs/proc/self.c +++ b/fs/proc/self.c @@ -12,7 +12,7 @@ static const char *proc_self_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { - struct pid_namespace *ns = proc_pid_ns(inode); + struct pid_namespace *ns = proc_pid_ns(inode->i_sb); pid_t tgid = task_tgid_nr_ns(current, ns); char *name; diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c index 2493cbbdfa6f..ac284f409568 100644 --- a/fs/proc/thread_self.c +++ b/fs/proc/thread_self.c @@ -12,7 +12,7 @@ static const char *proc_thread_self_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { - struct pid_namespace *ns = proc_pid_ns(inode); + struct pid_namespace *ns = proc_pid_ns(inode->i_sb); pid_t tgid = task_tgid_nr_ns(current, ns); pid_t pid = task_pid_nr_ns(current, ns); char *name; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 2cb424e6f36a..6ec524d8842c 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -202,9 +202,9 @@ int open_related_ns(struct ns_common *ns, struct ns_common *(*get_ns)(struct ns_common *ns)); /* get the associated pid namespace for a file in procfs */ -static inline struct pid_namespace *proc_pid_ns(const struct inode *inode) +static inline struct pid_namespace *proc_pid_ns(struct super_block *sb) { - return proc_sb_info(inode->i_sb)->pid_ns; + return proc_sb_info(sb)->pid_ns; } #endif /* _LINUX_PROC_FS_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 4385f3d639f2..e7bdaccad942 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1745,7 +1745,7 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f) pid_t nr = -1; if (likely(pid_has_task(pid, PIDTYPE_PID))) { - ns = proc_pid_ns(file_inode(m->file)); + ns = proc_pid_ns(file_inode(m->file)->i_sb); nr = pid_nr_ns(pid, ns); } diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c index d64b83e85642..ce4fbba4acce 100644 --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -779,7 +779,7 @@ static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos) { struct ip6fl_iter_state *state = ip6fl_seq_private(seq); - state->pid_ns = proc_pid_ns(file_inode(seq->file)); + state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb); rcu_read_lock_bh(); return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c index 08b096e2f7e3..df4798980416 100644 --- a/security/tomoyo/realpath.c +++ b/security/tomoyo/realpath.c @@ -162,7 +162,7 @@ static char *tomoyo_get_local_path(struct dentry *dentry, char * const buffer, if (sb->s_magic == PROC_SUPER_MAGIC && *pos == '/') { char *ep; const pid_t pid = (pid_t) simple_strtoul(pos + 1, &ep, 10); - struct pid_namespace *proc_pidns = proc_pid_ns(d_inode(dentry)); + struct pid_namespace *proc_pidns = proc_pid_ns(sb); if (*ep == '/' && pid && pid == task_tgid_nr_ns(current, proc_pidns)) {