13fb0e1ecf
commit 0d4370cfe36b7f1719123b621a4ec4d9c7a25f89 upstream.
If this is attempted by an io-wq kthread, then return -EOPNOTSUPP as we
don't currently support that. Once we can get task_pid_ptr() doing the
right thing, then this can go away again.
Use PF_IO_WORKER for this to speciically target the io_uring workers.
Modify the /proc/self/ check to use PF_IO_WORKER as well.
Cc: stable@vger.kernel.org
Fixes: 8d4c3e76e3 ("proc: don't allow async path resolution of /proc/self components")
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
81 lines
1.9 KiB
C
81 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/cache.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/pid_namespace.h>
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#include "internal.h"
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/*
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* /proc/self:
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*/
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static const char *proc_self_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
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pid_t tgid = task_tgid_nr_ns(current, ns);
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char *name;
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/*
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* Not currently supported. Once we can inherit all of struct pid,
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* we can allow this.
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*/
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if (current->flags & PF_IO_WORKER)
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return ERR_PTR(-EOPNOTSUPP);
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if (!tgid)
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return ERR_PTR(-ENOENT);
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/* max length of unsigned int in decimal + NULL term */
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name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
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if (unlikely(!name))
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return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
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sprintf(name, "%u", tgid);
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set_delayed_call(done, kfree_link, name);
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return name;
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}
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static const struct inode_operations proc_self_inode_operations = {
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.get_link = proc_self_get_link,
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};
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static unsigned self_inum __ro_after_init;
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int proc_setup_self(struct super_block *s)
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{
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struct inode *root_inode = d_inode(s->s_root);
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struct proc_fs_info *fs_info = proc_sb_info(s);
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struct dentry *self;
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int ret = -ENOMEM;
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inode_lock(root_inode);
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self = d_alloc_name(s->s_root, "self");
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if (self) {
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struct inode *inode = new_inode(s);
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if (inode) {
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inode->i_ino = self_inum;
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
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inode->i_mode = S_IFLNK | S_IRWXUGO;
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_op = &proc_self_inode_operations;
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d_add(self, inode);
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ret = 0;
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} else {
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dput(self);
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}
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}
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inode_unlock(root_inode);
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if (ret)
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pr_err("proc_fill_super: can't allocate /proc/self\n");
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else
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fs_info->proc_self = self;
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return ret;
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}
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void __init proc_self_init(void)
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{
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proc_alloc_inum(&self_inum);
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}
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