security/apparmor/include/file.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor file mediation function definitions.
   6  *
   7  * Copyright (C) 1998-2008 Novell/SUSE
   8  * Copyright 2009-2010 Canonical Ltd.
   9  */
  10
  11 #ifndef __AA_FILE_H
  12 #define __AA_FILE_H
  13
  14 #include <linux/spinlock.h>
  15
  16 #include "domain.h"
  17 #include "match.h"
  18 #include "perms.h"
  19
  20 struct aa_profile;
  21 struct path;
  22
  23 #define mask_mode_t(X) (X & (MAY_EXEC | MAY_WRITE | MAY_READ | MAY_APPEND))
  24
  25 #define AA_AUDIT_FILE_MASK      (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
  26                                  AA_MAY_CREATE | AA_MAY_DELETE |        \
  27                                  AA_MAY_GETATTR | AA_MAY_SETATTR | \
  28                                  AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
  29                                  AA_EXEC_MMAP | AA_MAY_LINK)
  30
  31 static inline struct aa_file_ctx *file_ctx(struct file *file)
  32 {
  33         return file->f_security + apparmor_blob_sizes.lbs_file;
  34 }
  35
  36 /* struct aa_file_ctx - the AppArmor context the file was opened in
  37  * @lock: lock to update the ctx
  38  * @label: label currently cached on the ctx
  39  * @perms: the permission the file was opened with
  40  */
  41 struct aa_file_ctx {
  42         spinlock_t lock;
  43         struct aa_label __rcu *label;
  44         u32 allow;
  45 };
  46
  47 /**
  48  * aa_alloc_file_ctx - allocate file_ctx
  49  * @label: initial label of task creating the file
  50  * @gfp: gfp flags for allocation
  51  *
  52  * Returns: file_ctx or NULL on failure
  53  */
  54 static inline struct aa_file_ctx *aa_alloc_file_ctx(struct aa_label *label,
  55                                                     gfp_t gfp)
  56 {
  57         struct aa_file_ctx *ctx;
  58
  59         ctx = kzalloc(sizeof(struct aa_file_ctx), gfp);
  60         if (ctx) {
  61                 spin_lock_init(&ctx->lock);
  62                 rcu_assign_pointer(ctx->label, aa_get_label(label));
  63         }
  64         return ctx;
  65 }
  66
  67 /**
  68  * aa_free_file_ctx - free a file_ctx
  69  * @ctx: file_ctx to free  (MAYBE_NULL)
  70  */
  71 static inline void aa_free_file_ctx(struct aa_file_ctx *ctx)
  72 {
  73         if (ctx) {
  74                 aa_put_label(rcu_access_pointer(ctx->label));
  75                 kfree_sensitive(ctx);
  76         }
  77 }
  78
  79 static inline struct aa_label *aa_get_file_label(struct aa_file_ctx *ctx)
  80 {
  81         return aa_get_label_rcu(&ctx->label);
  82 }
  83
  84 /*
  85  * The xindex is broken into 3 parts
  86  * - index - an index into either the exec name table or the variable table
  87  * - exec type - which determines how the executable name and index are used
  88  * - flags - which modify how the destination name is applied
  89  */
  90 #define AA_X_INDEX_MASK         0x03ff
  91
  92 #define AA_X_TYPE_MASK          0x0c00
  93 #define AA_X_TYPE_SHIFT         10
  94 #define AA_X_NONE               0x0000
  95 #define AA_X_NAME               0x0400  /* use executable name px */
  96 #define AA_X_TABLE              0x0800  /* use a specified name ->n# */
  97
  98 #define AA_X_UNSAFE             0x1000
  99 #define AA_X_CHILD              0x2000  /* make >AA_X_NONE apply to children */
 100 #define AA_X_INHERIT            0x4000
 101 #define AA_X_UNCONFINED         0x8000
 102
 103 /* need to make conditional which ones are being set */
 104 struct path_cond {
 105         kuid_t uid;
 106         umode_t mode;
 107 };
 108
 109 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
 110
 111 /* FIXME: split perms from dfa and match this to description
 112  *        also add delegation info.
 113  */
 114 static inline u16 dfa_map_xindex(u16 mask)
 115 {
 116         u16 old_index = (mask >> 10) & 0xf;
 117         u16 index = 0;
 118
 119         if (mask & 0x100)
 120                 index |= AA_X_UNSAFE;
 121         if (mask & 0x200)
 122                 index |= AA_X_INHERIT;
 123         if (mask & 0x80)
 124                 index |= AA_X_UNCONFINED;
 125
 126         if (old_index == 1) {
 127                 index |= AA_X_UNCONFINED;
 128         } else if (old_index == 2) {
 129                 index |= AA_X_NAME;
 130         } else if (old_index == 3) {
 131                 index |= AA_X_NAME | AA_X_CHILD;
 132         } else if (old_index) {
 133                 index |= AA_X_TABLE;
 134                 index |= old_index - 4;
 135         }
 136
 137         return index;
 138 }
 139
 140 /*
 141  * map old dfa inline permissions to new format
 142  */
 143 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
 144                                     ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 145 #define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
 146 #define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
 147 #define dfa_user_xindex(dfa, state) \
 148         (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
 149
 150 #define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
 151                                       0x7f) |                           \
 152                                      ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
 153 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
 154 #define dfa_other_quiet(dfa, state) \
 155         ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
 156 #define dfa_other_xindex(dfa, state) \
 157         dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
 158
 159 int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
 160                   const char *op, u32 request, const char *name,
 161                   const char *target, struct aa_label *tlabel, kuid_t ouid,
 162                   const char *info, int error);
 163
 164 /**
 165  * struct aa_file_rules - components used for file rule permissions
 166  * @dfa: dfa to match path names and conditionals against
 167  * @perms: permission table indexed by the matched state accept entry of @dfa
 168  * @trans: transition table for indexed by named x transitions
 169  *
 170  * File permission are determined by matching a path against @dfa and then
 171  * then using the value of the accept entry for the matching state as
 172  * an index into @perms.  If a named exec transition is required it is
 173  * looked up in the transition table.
 174  */
 175 struct aa_file_rules {
 176         unsigned int start;
 177         struct aa_dfa *dfa;
 178         /* struct perms perms; */
 179         struct aa_domain trans;
 180         /* TODO: add delegate table */
 181 };
 182
 183 struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
 184                                     struct path_cond *cond);
 185 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
 186                           const char *name, struct path_cond *cond,
 187                           struct aa_perms *perms);
 188
 189 int __aa_path_perm(const char *op, struct aa_profile *profile,
 190                    const char *name, u32 request, struct path_cond *cond,
 191                    int flags, struct aa_perms *perms);
 192 int aa_path_perm(const char *op, struct aa_label *label,
 193                  const struct path *path, int flags, u32 request,
 194                  struct path_cond *cond);
 195
 196 int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
 197                  const struct path *new_dir, struct dentry *new_dentry);
 198
 199 int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
 200                  u32 request, bool in_atomic);
 201
 202 void aa_inherit_files(const struct cred *cred, struct files_struct *files);
 203
 204 static inline void aa_free_file_rules(struct aa_file_rules *rules)
 205 {
 206         aa_put_dfa(rules->dfa);
 207         aa_free_domain_entries(&rules->trans);
 208 }
 209
 210 /**
 211  * aa_map_file_perms - map file flags to AppArmor permissions
 212  * @file: open file to map flags to AppArmor permissions
 213  *
 214  * Returns: apparmor permission set for the file
 215  */
 216 static inline u32 aa_map_file_to_perms(struct file *file)
 217 {
 218         int flags = file->f_flags;
 219         u32 perms = 0;
 220
 221         if (file->f_mode & FMODE_WRITE)
 222                 perms |= MAY_WRITE;
 223         if (file->f_mode & FMODE_READ)
 224                 perms |= MAY_READ;
 225
 226         if ((flags & O_APPEND) && (perms & MAY_WRITE))
 227                 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
 228         /* trunc implies write permission */
 229         if (flags & O_TRUNC)
 230                 perms |= MAY_WRITE;
 231         if (flags & O_CREAT)
 232                 perms |= AA_MAY_CREATE;
 233
 234         return perms;
 235 }
 236
 237 #endif /* __AA_FILE_H */