On Thu, Nov 10, 2016 at 4:18 PM, Andreas Gruenbacher
<agruenba@xxxxxxxxxx> wrote:
> Pass the file mode of the proc inode to be created to
> proc_pid_make_inode. In proc_pid_make_inode, initialize inode->i_mode
> before calling security_task_to_inode. This allows selinux to set
> isec->sclass right away without introducing "half-initialized" inode
> security structs.
>
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> fs/proc/base.c | 23 +++++++++--------------
> fs/proc/fd.c | 6 ++----
> fs/proc/internal.h | 2 +-
> fs/proc/namespaces.c | 3 +--
> security/selinux/hooks.c | 1 +
> 5 files changed, 14 insertions(+), 21 deletions(-)
Seems reasonable, merged.
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index ca651ac..6eae4d0 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -1664,7 +1664,8 @@ const struct inode_operations proc_pid_link_inode_operations = {
>
> /* building an inode */
>
> -struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task)
> +struct inode *proc_pid_make_inode(struct super_block * sb,
> + struct task_struct *task, umode_t mode)
> {
> struct inode * inode;
> struct proc_inode *ei;
> @@ -1678,6 +1679,7 @@ struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *t
>
> /* Common stuff */
> ei = PROC_I(inode);
> + inode->i_mode = mode;
> inode->i_ino = get_next_ino();
> inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
> inode->i_op = &proc_def_inode_operations;
> @@ -2004,7 +2006,9 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
> struct proc_inode *ei;
> struct inode *inode;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK |
> + ((mode & FMODE_READ ) ? S_IRUSR : 0) |
> + ((mode & FMODE_WRITE) ? S_IWUSR : 0));
> if (!inode)
> return -ENOENT;
>
> @@ -2013,12 +2017,6 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
>
> inode->i_op = &proc_map_files_link_inode_operations;
> inode->i_size = 64;
> - inode->i_mode = S_IFLNK;
> -
> - if (mode & FMODE_READ)
> - inode->i_mode |= S_IRUSR;
> - if (mode & FMODE_WRITE)
> - inode->i_mode |= S_IWUSR;
>
> d_set_d_op(dentry, &tid_map_files_dentry_operations);
> d_add(dentry, inode);
> @@ -2372,12 +2370,11 @@ static int proc_pident_instantiate(struct inode *dir,
> struct inode *inode;
> struct proc_inode *ei;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, p->mode);
> if (!inode)
> goto out;
>
> ei = PROC_I(inode);
> - inode->i_mode = p->mode;
> if (S_ISDIR(inode->i_mode))
> set_nlink(inode, 2); /* Use getattr to fix if necessary */
> if (p->iop)
> @@ -3059,11 +3056,10 @@ static int proc_pid_instantiate(struct inode *dir,
> {
> struct inode *inode;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
> if (!inode)
> goto out;
>
> - inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
> inode->i_op = &proc_tgid_base_inode_operations;
> inode->i_fop = &proc_tgid_base_operations;
> inode->i_flags|=S_IMMUTABLE;
> @@ -3352,11 +3348,10 @@ static int proc_task_instantiate(struct inode *dir,
> struct dentry *dentry, struct task_struct *task, const void *ptr)
> {
> struct inode *inode;
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
>
> if (!inode)
> goto out;
> - inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
> inode->i_op = &proc_tid_base_inode_operations;
> inode->i_fop = &proc_tid_base_operations;
> inode->i_flags|=S_IMMUTABLE;
> diff --git a/fs/proc/fd.c b/fs/proc/fd.c
> index d21dafe..4274f83 100644
> --- a/fs/proc/fd.c
> +++ b/fs/proc/fd.c
> @@ -183,14 +183,13 @@ proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
> struct proc_inode *ei;
> struct inode *inode;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK);
> if (!inode)
> goto out;
>
> ei = PROC_I(inode);
> ei->fd = fd;
>
> - inode->i_mode = S_IFLNK;
> inode->i_op = &proc_pid_link_inode_operations;
> inode->i_size = 64;
>
> @@ -322,14 +321,13 @@ proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
> struct proc_inode *ei;
> struct inode *inode;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR);
> if (!inode)
> goto out;
>
> ei = PROC_I(inode);
> ei->fd = fd;
>
> - inode->i_mode = S_IFREG | S_IRUSR;
> inode->i_fop = &proc_fdinfo_file_operations;
>
> d_set_d_op(dentry, &tid_fd_dentry_operations);
> diff --git a/fs/proc/internal.h b/fs/proc/internal.h
> index 5378441..f4494dc 100644
> --- a/fs/proc/internal.h
> +++ b/fs/proc/internal.h
> @@ -162,7 +162,7 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
> extern const struct dentry_operations pid_dentry_operations;
> extern int pid_getattr(struct vfsmount *, struct dentry *, struct kstat *);
> extern int proc_setattr(struct dentry *, struct iattr *);
> -extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *);
> +extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
> extern int pid_revalidate(struct dentry *, unsigned int);
> extern int pid_delete_dentry(const struct dentry *);
> extern int proc_pid_readdir(struct file *, struct dir_context *);
> diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
> index 51b8b0a..766f0c6 100644
> --- a/fs/proc/namespaces.c
> +++ b/fs/proc/namespaces.c
> @@ -92,12 +92,11 @@ static int proc_ns_instantiate(struct inode *dir,
> struct inode *inode;
> struct proc_inode *ei;
>
> - inode = proc_pid_make_inode(dir->i_sb, task);
> + inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO);
> if (!inode)
> goto out;
>
> ei = PROC_I(inode);
> - inode->i_mode = S_IFLNK|S_IRWXUGO;
> inode->i_op = &proc_ns_link_inode_operations;
> ei->ns_ops = ns_ops;
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index b98ab2a..e4527d9 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -3954,6 +3954,7 @@ static void selinux_task_to_inode(struct task_struct *p,
> struct inode_security_struct *isec = inode->i_security;
> u32 sid = task_sid(p);
>
> + isec->sclass = inode_mode_to_security_class(inode->i_mode);
> isec->sid = sid;
> isec->initialized = LABEL_INITIALIZED;
> }
> --
> 2.7.4
>
--
paul moore
www.paul-moore.com
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