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[23.128.96.18]) by mx.google.com with ESMTP id c22si6674190eds.427.2020.05.18.11.12.51; Mon, 18 May 2020 11:13:15 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387498AbgERSIY (ORCPT + 99 others); Mon, 18 May 2020 14:08:24 -0400 Received: from raptor.unsafe.ru ([5.9.43.93]:35962 "EHLO raptor.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733067AbgERSHv (ORCPT ); Mon, 18 May 2020 14:07:51 -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 9201D20479; Mon, 18 May 2020 18:07:42 +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 v4] proc: proc_pid_ns takes super_block as an argument Date: Mon, 18 May 2020 20:07:38 +0200 Message-Id: <20200518180738.2939611-1-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 Content-Transfer-Encoding: 8bit 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 18:07:45 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot found that touch /proc/testfile causes NULL pointer dereference at tomoyo_get_local_path() because inode of the dentry is NULL. 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, change the argument type of the proc_pid_ns() function. Then, 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)) { -- 2.25.4