Commit 3ed02ada2a5e695e2fbb5e4a0008cfcb0f50feaa
Committed by
James Morris
James Morris
1 parent
9f1c1d426b
Exists in
master
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20 other branches
AppArmor: Ensure the size of the copy is < the buffer allocated to hold it
Actually I think in this case the appropriate thing to do is to BUG as there is currently a case (remove) where the alloc_size needs to be larger than the copy_size, and if copy_size is ever greater than alloc_size there is a mistake in the caller code. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Kees Cook <kees.cook@canonical.com> Signed-off-by: James Morris <jmorris@namei.org>
Showing 1 changed file with 3 additions and 1 deletions Inline Diff
security/apparmor/apparmorfs.c
| 1 | /* | 1 | /* |
| 2 | * AppArmor security module | 2 | * AppArmor security module |
| 3 | * | 3 | * |
| 4 | * This file contains AppArmor /sys/kernel/security/apparmor interface functions | 4 | * This file contains AppArmor /sys/kernel/security/apparmor interface functions |
| 5 | * | 5 | * |
| 6 | * Copyright (C) 1998-2008 Novell/SUSE | 6 | * Copyright (C) 1998-2008 Novell/SUSE |
| 7 | * Copyright 2009-2010 Canonical Ltd. | 7 | * Copyright 2009-2010 Canonical Ltd. |
| 8 | * | 8 | * |
| 9 | * This program is free software; you can redistribute it and/or | 9 | * This program is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU General Public License as | 10 | * modify it under the terms of the GNU General Public License as |
| 11 | * published by the Free Software Foundation, version 2 of the | 11 | * published by the Free Software Foundation, version 2 of the |
| 12 | * License. | 12 | * License. |
| 13 | */ | 13 | */ |
| 14 | 14 | ||
| 15 | #include <linux/security.h> | 15 | #include <linux/security.h> |
| 16 | #include <linux/vmalloc.h> | 16 | #include <linux/vmalloc.h> |
| 17 | #include <linux/module.h> | 17 | #include <linux/module.h> |
| 18 | #include <linux/seq_file.h> | 18 | #include <linux/seq_file.h> |
| 19 | #include <linux/uaccess.h> | 19 | #include <linux/uaccess.h> |
| 20 | #include <linux/namei.h> | 20 | #include <linux/namei.h> |
| 21 | 21 | ||
| 22 | #include "include/apparmor.h" | 22 | #include "include/apparmor.h" |
| 23 | #include "include/apparmorfs.h" | 23 | #include "include/apparmorfs.h" |
| 24 | #include "include/audit.h" | 24 | #include "include/audit.h" |
| 25 | #include "include/context.h" | 25 | #include "include/context.h" |
| 26 | #include "include/policy.h" | 26 | #include "include/policy.h" |
| 27 | 27 | ||
| 28 | /** | 28 | /** |
| 29 | * aa_simple_write_to_buffer - common routine for getting policy from user | 29 | * aa_simple_write_to_buffer - common routine for getting policy from user |
| 30 | * @op: operation doing the user buffer copy | 30 | * @op: operation doing the user buffer copy |
| 31 | * @userbuf: user buffer to copy data from (NOT NULL) | 31 | * @userbuf: user buffer to copy data from (NOT NULL) |
| 32 | * @alloc_size: size of user buffer | 32 | * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) |
| 33 | * @copy_size: size of data to copy from user buffer | 33 | * @copy_size: size of data to copy from user buffer |
| 34 | * @pos: position write is at in the file (NOT NULL) | 34 | * @pos: position write is at in the file (NOT NULL) |
| 35 | * | 35 | * |
| 36 | * Returns: kernel buffer containing copy of user buffer data or an | 36 | * Returns: kernel buffer containing copy of user buffer data or an |
| 37 | * ERR_PTR on failure. | 37 | * ERR_PTR on failure. |
| 38 | */ | 38 | */ |
| 39 | static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, | 39 | static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, |
| 40 | size_t alloc_size, size_t copy_size, | 40 | size_t alloc_size, size_t copy_size, |
| 41 | loff_t *pos) | 41 | loff_t *pos) |
| 42 | { | 42 | { |
| 43 | char *data; | 43 | char *data; |
| 44 | |||
| 45 | BUG_ON(copy_size > alloc_size); | ||
| 44 | 46 | ||
| 45 | if (*pos != 0) | 47 | if (*pos != 0) |
| 46 | /* only writes from pos 0, that is complete writes */ | 48 | /* only writes from pos 0, that is complete writes */ |
| 47 | return ERR_PTR(-ESPIPE); | 49 | return ERR_PTR(-ESPIPE); |
| 48 | 50 | ||
| 49 | /* | 51 | /* |
| 50 | * Don't allow profile load/replace/remove from profiles that don't | 52 | * Don't allow profile load/replace/remove from profiles that don't |
| 51 | * have CAP_MAC_ADMIN | 53 | * have CAP_MAC_ADMIN |
| 52 | */ | 54 | */ |
| 53 | if (!aa_may_manage_policy(op)) | 55 | if (!aa_may_manage_policy(op)) |
| 54 | return ERR_PTR(-EACCES); | 56 | return ERR_PTR(-EACCES); |
| 55 | 57 | ||
| 56 | /* freed by caller to simple_write_to_buffer */ | 58 | /* freed by caller to simple_write_to_buffer */ |
| 57 | data = kvmalloc(alloc_size); | 59 | data = kvmalloc(alloc_size); |
| 58 | if (data == NULL) | 60 | if (data == NULL) |
| 59 | return ERR_PTR(-ENOMEM); | 61 | return ERR_PTR(-ENOMEM); |
| 60 | 62 | ||
| 61 | if (copy_from_user(data, userbuf, copy_size)) { | 63 | if (copy_from_user(data, userbuf, copy_size)) { |
| 62 | kvfree(data); | 64 | kvfree(data); |
| 63 | return ERR_PTR(-EFAULT); | 65 | return ERR_PTR(-EFAULT); |
| 64 | } | 66 | } |
| 65 | 67 | ||
| 66 | return data; | 68 | return data; |
| 67 | } | 69 | } |
| 68 | 70 | ||
| 69 | 71 | ||
| 70 | /* .load file hook fn to load policy */ | 72 | /* .load file hook fn to load policy */ |
| 71 | static ssize_t profile_load(struct file *f, const char __user *buf, size_t size, | 73 | static ssize_t profile_load(struct file *f, const char __user *buf, size_t size, |
| 72 | loff_t *pos) | 74 | loff_t *pos) |
| 73 | { | 75 | { |
| 74 | char *data; | 76 | char *data; |
| 75 | ssize_t error; | 77 | ssize_t error; |
| 76 | 78 | ||
| 77 | data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos); | 79 | data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos); |
| 78 | 80 | ||
| 79 | error = PTR_ERR(data); | 81 | error = PTR_ERR(data); |
| 80 | if (!IS_ERR(data)) { | 82 | if (!IS_ERR(data)) { |
| 81 | error = aa_replace_profiles(data, size, PROF_ADD); | 83 | error = aa_replace_profiles(data, size, PROF_ADD); |
| 82 | kvfree(data); | 84 | kvfree(data); |
| 83 | } | 85 | } |
| 84 | 86 | ||
| 85 | return error; | 87 | return error; |
| 86 | } | 88 | } |
| 87 | 89 | ||
| 88 | static const struct file_operations aa_fs_profile_load = { | 90 | static const struct file_operations aa_fs_profile_load = { |
| 89 | .write = profile_load | 91 | .write = profile_load |
| 90 | }; | 92 | }; |
| 91 | 93 | ||
| 92 | /* .replace file hook fn to load and/or replace policy */ | 94 | /* .replace file hook fn to load and/or replace policy */ |
| 93 | static ssize_t profile_replace(struct file *f, const char __user *buf, | 95 | static ssize_t profile_replace(struct file *f, const char __user *buf, |
| 94 | size_t size, loff_t *pos) | 96 | size_t size, loff_t *pos) |
| 95 | { | 97 | { |
| 96 | char *data; | 98 | char *data; |
| 97 | ssize_t error; | 99 | ssize_t error; |
| 98 | 100 | ||
| 99 | data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); | 101 | data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); |
| 100 | error = PTR_ERR(data); | 102 | error = PTR_ERR(data); |
| 101 | if (!IS_ERR(data)) { | 103 | if (!IS_ERR(data)) { |
| 102 | error = aa_replace_profiles(data, size, PROF_REPLACE); | 104 | error = aa_replace_profiles(data, size, PROF_REPLACE); |
| 103 | kvfree(data); | 105 | kvfree(data); |
| 104 | } | 106 | } |
| 105 | 107 | ||
| 106 | return error; | 108 | return error; |
| 107 | } | 109 | } |
| 108 | 110 | ||
| 109 | static const struct file_operations aa_fs_profile_replace = { | 111 | static const struct file_operations aa_fs_profile_replace = { |
| 110 | .write = profile_replace | 112 | .write = profile_replace |
| 111 | }; | 113 | }; |
| 112 | 114 | ||
| 113 | /* .remove file hook fn to remove loaded policy */ | 115 | /* .remove file hook fn to remove loaded policy */ |
| 114 | static ssize_t profile_remove(struct file *f, const char __user *buf, | 116 | static ssize_t profile_remove(struct file *f, const char __user *buf, |
| 115 | size_t size, loff_t *pos) | 117 | size_t size, loff_t *pos) |
| 116 | { | 118 | { |
| 117 | char *data; | 119 | char *data; |
| 118 | ssize_t error; | 120 | ssize_t error; |
| 119 | 121 | ||
| 120 | /* | 122 | /* |
| 121 | * aa_remove_profile needs a null terminated string so 1 extra | 123 | * aa_remove_profile needs a null terminated string so 1 extra |
| 122 | * byte is allocated and the copied data is null terminated. | 124 | * byte is allocated and the copied data is null terminated. |
| 123 | */ | 125 | */ |
| 124 | data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); | 126 | data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); |
| 125 | 127 | ||
| 126 | error = PTR_ERR(data); | 128 | error = PTR_ERR(data); |
| 127 | if (!IS_ERR(data)) { | 129 | if (!IS_ERR(data)) { |
| 128 | data[size] = 0; | 130 | data[size] = 0; |
| 129 | error = aa_remove_profiles(data, size); | 131 | error = aa_remove_profiles(data, size); |
| 130 | kvfree(data); | 132 | kvfree(data); |
| 131 | } | 133 | } |
| 132 | 134 | ||
| 133 | return error; | 135 | return error; |
| 134 | } | 136 | } |
| 135 | 137 | ||
| 136 | static const struct file_operations aa_fs_profile_remove = { | 138 | static const struct file_operations aa_fs_profile_remove = { |
| 137 | .write = profile_remove | 139 | .write = profile_remove |
| 138 | }; | 140 | }; |
| 139 | 141 | ||
| 140 | /** Base file system setup **/ | 142 | /** Base file system setup **/ |
| 141 | 143 | ||
| 142 | static struct dentry *aa_fs_dentry __initdata; | 144 | static struct dentry *aa_fs_dentry __initdata; |
| 143 | 145 | ||
| 144 | static void __init aafs_remove(const char *name) | 146 | static void __init aafs_remove(const char *name) |
| 145 | { | 147 | { |
| 146 | struct dentry *dentry; | 148 | struct dentry *dentry; |
| 147 | 149 | ||
| 148 | dentry = lookup_one_len(name, aa_fs_dentry, strlen(name)); | 150 | dentry = lookup_one_len(name, aa_fs_dentry, strlen(name)); |
| 149 | if (!IS_ERR(dentry)) { | 151 | if (!IS_ERR(dentry)) { |
| 150 | securityfs_remove(dentry); | 152 | securityfs_remove(dentry); |
| 151 | dput(dentry); | 153 | dput(dentry); |
| 152 | } | 154 | } |
| 153 | } | 155 | } |
| 154 | 156 | ||
| 155 | /** | 157 | /** |
| 156 | * aafs_create - create an entry in the apparmor filesystem | 158 | * aafs_create - create an entry in the apparmor filesystem |
| 157 | * @name: name of the entry (NOT NULL) | 159 | * @name: name of the entry (NOT NULL) |
| 158 | * @mask: file permission mask of the file | 160 | * @mask: file permission mask of the file |
| 159 | * @fops: file operations for the file (NOT NULL) | 161 | * @fops: file operations for the file (NOT NULL) |
| 160 | * | 162 | * |
| 161 | * Used aafs_remove to remove entries created with this fn. | 163 | * Used aafs_remove to remove entries created with this fn. |
| 162 | */ | 164 | */ |
| 163 | static int __init aafs_create(const char *name, int mask, | 165 | static int __init aafs_create(const char *name, int mask, |
| 164 | const struct file_operations *fops) | 166 | const struct file_operations *fops) |
| 165 | { | 167 | { |
| 166 | struct dentry *dentry; | 168 | struct dentry *dentry; |
| 167 | 169 | ||
| 168 | dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry, | 170 | dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry, |
| 169 | NULL, fops); | 171 | NULL, fops); |
| 170 | 172 | ||
| 171 | return IS_ERR(dentry) ? PTR_ERR(dentry) : 0; | 173 | return IS_ERR(dentry) ? PTR_ERR(dentry) : 0; |
| 172 | } | 174 | } |
| 173 | 175 | ||
| 174 | /** | 176 | /** |
| 175 | * aa_destroy_aafs - cleanup and free aafs | 177 | * aa_destroy_aafs - cleanup and free aafs |
| 176 | * | 178 | * |
| 177 | * releases dentries allocated by aa_create_aafs | 179 | * releases dentries allocated by aa_create_aafs |
| 178 | */ | 180 | */ |
| 179 | void __init aa_destroy_aafs(void) | 181 | void __init aa_destroy_aafs(void) |
| 180 | { | 182 | { |
| 181 | if (aa_fs_dentry) { | 183 | if (aa_fs_dentry) { |
| 182 | aafs_remove(".remove"); | 184 | aafs_remove(".remove"); |
| 183 | aafs_remove(".replace"); | 185 | aafs_remove(".replace"); |
| 184 | aafs_remove(".load"); | 186 | aafs_remove(".load"); |
| 185 | 187 | ||
| 186 | securityfs_remove(aa_fs_dentry); | 188 | securityfs_remove(aa_fs_dentry); |
| 187 | aa_fs_dentry = NULL; | 189 | aa_fs_dentry = NULL; |
| 188 | } | 190 | } |
| 189 | } | 191 | } |
| 190 | 192 | ||
| 191 | /** | 193 | /** |
| 192 | * aa_create_aafs - create the apparmor security filesystem | 194 | * aa_create_aafs - create the apparmor security filesystem |
| 193 | * | 195 | * |
| 194 | * dentries created here are released by aa_destroy_aafs | 196 | * dentries created here are released by aa_destroy_aafs |
| 195 | * | 197 | * |
| 196 | * Returns: error on failure | 198 | * Returns: error on failure |
| 197 | */ | 199 | */ |
| 198 | int __init aa_create_aafs(void) | 200 | int __init aa_create_aafs(void) |
| 199 | { | 201 | { |
| 200 | int error; | 202 | int error; |
| 201 | 203 | ||
| 202 | if (!apparmor_initialized) | 204 | if (!apparmor_initialized) |
| 203 | return 0; | 205 | return 0; |
| 204 | 206 | ||
| 205 | if (aa_fs_dentry) { | 207 | if (aa_fs_dentry) { |
| 206 | AA_ERROR("%s: AppArmor securityfs already exists\n", __func__); | 208 | AA_ERROR("%s: AppArmor securityfs already exists\n", __func__); |
| 207 | return -EEXIST; | 209 | return -EEXIST; |
| 208 | } | 210 | } |
| 209 | 211 | ||
| 210 | aa_fs_dentry = securityfs_create_dir("apparmor", NULL); | 212 | aa_fs_dentry = securityfs_create_dir("apparmor", NULL); |
| 211 | if (IS_ERR(aa_fs_dentry)) { | 213 | if (IS_ERR(aa_fs_dentry)) { |
| 212 | error = PTR_ERR(aa_fs_dentry); | 214 | error = PTR_ERR(aa_fs_dentry); |
| 213 | aa_fs_dentry = NULL; | 215 | aa_fs_dentry = NULL; |
| 214 | goto error; | 216 | goto error; |
| 215 | } | 217 | } |
| 216 | 218 | ||
| 217 | error = aafs_create(".load", 0640, &aa_fs_profile_load); | 219 | error = aafs_create(".load", 0640, &aa_fs_profile_load); |
| 218 | if (error) | 220 | if (error) |
| 219 | goto error; | 221 | goto error; |
| 220 | error = aafs_create(".replace", 0640, &aa_fs_profile_replace); | 222 | error = aafs_create(".replace", 0640, &aa_fs_profile_replace); |
| 221 | if (error) | 223 | if (error) |
| 222 | goto error; | 224 | goto error; |
| 223 | error = aafs_create(".remove", 0640, &aa_fs_profile_remove); | 225 | error = aafs_create(".remove", 0640, &aa_fs_profile_remove); |
| 224 | if (error) | 226 | if (error) |
| 225 | goto error; | 227 | goto error; |
| 226 | 228 | ||
| 227 | /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ | 229 | /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ |
| 228 | 230 | ||
| 229 | /* Report that AppArmor fs is enabled */ | 231 | /* Report that AppArmor fs is enabled */ |
| 230 | aa_info_message("AppArmor Filesystem Enabled"); | 232 | aa_info_message("AppArmor Filesystem Enabled"); |
| 231 | return 0; | 233 | return 0; |
| 232 | 234 | ||
| 233 | error: | 235 | error: |
| 234 | aa_destroy_aafs(); | 236 | aa_destroy_aafs(); |
| 235 | AA_ERROR("Error creating AppArmor securityfs\n"); | 237 | AA_ERROR("Error creating AppArmor securityfs\n"); |
| 236 | return error; | 238 | return error; |
| 237 | } | 239 | } |
| 238 | 240 | ||
| 239 | fs_initcall(aa_create_aafs); | 241 | fs_initcall(aa_create_aafs); |
| 240 | 242 |