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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223// SPDX-License-Identifier: GPL-2.0-only/* * AppArmor security module * * This file contains AppArmor function for pathnames * * Copyright (C) 1998-2008 Novell/SUSE * Copyright 2009-2010 Canonical Ltd. */
#include <linux/magic.h>#include <linux/mount.h>#include <linux/namei.h>#include <linux/nsproxy.h>#include <linux/path.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/fs_struct.h>
#include "include/apparmor.h"#include "include/path.h"#include "include/policy.h"
/* modified from dcache.c */static int prepend(char **buffer, int buflen, const char *str, int namelen){ buflen -= namelen; if (buflen < 0) return -ENAMETOOLONG; *buffer -= namelen; memcpy(*buffer, str, namelen); return 0;}
#define CHROOT_NSCONNECT (PATH_CHROOT_REL | PATH_CHROOT_NSCONNECT)
/* If the path is not connected to the expected root, * check if it is a sysctl and handle specially else remove any * leading / that __d_path may have returned. * Unless * specifically directed to connect the path, * OR * if in a chroot and doing chroot relative paths and the path * resolves to the namespace root (would be connected outside * of chroot) and specifically directed to connect paths to * namespace root. */static int disconnect(const struct path *path, char *buf, char **name, int flags, const char *disconnected){ int error = 0;
if (!(flags & PATH_CONNECT_PATH) && !(((flags & CHROOT_NSCONNECT) == CHROOT_NSCONNECT) && our_mnt(path->mnt))) { /* disconnected path, don't return pathname starting * with '/' */ error = -EACCES; if (**name == '/') *name = *name + 1; } else { if (**name != '/') /* CONNECT_PATH with missing root */ error = prepend(name, *name - buf, "/", 1); if (!error && disconnected) error = prepend(name, *name - buf, disconnected, strlen(disconnected)); }
return error;}
/** * d_namespace_path - lookup a name associated with a given path * @path: path to lookup (NOT NULL) * @buf: buffer to store path to (NOT NULL) * @name: Returns - pointer for start of path name with in @buf (NOT NULL) * @flags: flags controlling path lookup * @disconnected: string to prefix to disconnected paths * * Handle path name lookup. * * Returns: %0 else error code if path lookup fails * When no error the path name is returned in @name which points to * a position in @buf */static int d_namespace_path(const struct path *path, char *buf, char **name, int flags, const char *disconnected){ char *res; int error = 0; int connected = 1; int isdir = (flags & PATH_IS_DIR) ? 1 : 0; int buflen = aa_g_path_max - isdir;
if (path->mnt->mnt_flags & MNT_INTERNAL) { /* it's not mounted anywhere */ res = dentry_path(path->dentry, buf, buflen); *name = res; if (IS_ERR(res)) { *name = buf; return PTR_ERR(res); } if (path->dentry->d_sb->s_magic == PROC_SUPER_MAGIC && strncmp(*name, "/sys/", 5) == 0) { /* TODO: convert over to using a per namespace * control instead of hard coded /proc */ error = prepend(name, *name - buf, "/proc", 5); goto out; } else error = disconnect(path, buf, name, flags, disconnected); goto out; }
/* resolve paths relative to chroot?*/ if (flags & PATH_CHROOT_REL) { struct path root; get_fs_root(current->fs, &root); res = __d_path(path, &root, buf, buflen); path_put(&root); } else { res = d_absolute_path(path, buf, buflen); if (!our_mnt(path->mnt)) connected = 0; }
/* handle error conditions - and still allow a partial path to * be returned. */ if (IS_ERR_OR_NULL(res)) { if (PTR_ERR(res) == -ENAMETOOLONG) { error = -ENAMETOOLONG; *name = buf; goto out; } connected = 0; res = dentry_path_raw(path->dentry, buf, buflen); if (IS_ERR(res)) { error = PTR_ERR(res); *name = buf; goto out; } } else if (!our_mnt(path->mnt)) connected = 0;
*name = res;
if (!connected) error = disconnect(path, buf, name, flags, disconnected);
/* Handle two cases: * 1. A deleted dentry && profile is not allowing mediation of deleted * 2. On some filesystems, newly allocated dentries appear to the * security_path hooks as a deleted dentry except without an inode * allocated. */ if (d_unlinked(path->dentry) && d_is_positive(path->dentry) && !(flags & (PATH_MEDIATE_DELETED | PATH_DELEGATE_DELETED))) { error = -ENOENT; goto out; }
out: /* Append "/" to directory paths and reterminate string, except for * root "/" which already ends in a slash. */ if (!error && isdir) { bool is_root = (*name)[0] == '/' && (*name)[1] == '\0';
if (!is_root) { buf[aa_g_path_max - 2] = '/'; buf[aa_g_path_max - 1] = '\0'; } }
return error;}
/** * aa_path_name - get the pathname to a buffer ensure dir / is appended * @path: path the file (NOT NULL) * @flags: flags controlling path name generation * @buffer: buffer to put name in (NOT NULL) * @name: Returns - the generated path name if !error (NOT NULL) * @info: Returns - information on why the path lookup failed (MAYBE NULL) * @disconnected: string to prepend to disconnected paths * * @name is a pointer to the beginning of the pathname (which usually differs * from the beginning of the buffer), or NULL. If there is an error @name * may contain a partial or invalid name that can be used for audit purposes, * but it can not be used for mediation. * * We need PATH_IS_DIR to indicate whether the file is a directory or not * because the file may not yet exist, and so we cannot check the inode's * file type. * * Returns: %0 else error code if could retrieve name */int aa_path_name(const struct path *path, int flags, char *buffer, const char **name, const char **info, const char *disconnected){ char *str = NULL; int error = d_namespace_path(path, buffer, &str, flags, disconnected);
if (info && error) { if (error == -ENOENT) *info = "Failed name lookup - deleted entry"; else if (error == -EACCES) *info = "Failed name lookup - disconnected path"; else if (error == -ENAMETOOLONG) *info = "Failed name lookup - name too long"; else *info = "Failed name lookup"; }
*name = str;
return error;}