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Diffstat (limited to 'fs/crypto/keysetup.c')
-rw-r--r--fs/crypto/keysetup.c109
1 files changed, 79 insertions, 30 deletions
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 302375e9f719..1129adfa097d 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -46,6 +46,8 @@ struct fscrypt_mode fscrypt_modes[] = {
},
};
+static DEFINE_MUTEX(fscrypt_mode_key_setup_mutex);
+
static struct fscrypt_mode *
select_encryption_mode(const union fscrypt_policy *policy,
const struct inode *inode)
@@ -130,7 +132,7 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
const struct super_block *sb = inode->i_sb;
struct fscrypt_mode *mode = ci->ci_mode;
const u8 mode_num = mode - fscrypt_modes;
- struct crypto_skcipher *tfm, *prev_tfm;
+ struct crypto_skcipher *tfm;
u8 mode_key[FSCRYPT_MAX_KEY_SIZE];
u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];
unsigned int hkdf_infolen = 0;
@@ -139,10 +141,17 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX))
return -EINVAL;
- /* pairs with cmpxchg() below */
+ /* pairs with smp_store_release() below */
tfm = READ_ONCE(tfms[mode_num]);
- if (likely(tfm != NULL))
- goto done;
+ if (likely(tfm != NULL)) {
+ ci->ci_ctfm = tfm;
+ return 0;
+ }
+
+ mutex_lock(&fscrypt_mode_key_setup_mutex);
+
+ if (tfms[mode_num])
+ goto done_unlock;
BUILD_BUG_ON(sizeof(mode_num) != 1);
BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);
@@ -157,21 +166,21 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
hkdf_context, hkdf_info, hkdf_infolen,
mode_key, mode->keysize);
if (err)
- return err;
+ goto out_unlock;
tfm = fscrypt_allocate_skcipher(mode, mode_key, inode);
memzero_explicit(mode_key, mode->keysize);
- if (IS_ERR(tfm))
- return PTR_ERR(tfm);
-
- /* pairs with READ_ONCE() above */
- prev_tfm = cmpxchg(&tfms[mode_num], NULL, tfm);
- if (prev_tfm != NULL) {
- crypto_free_skcipher(tfm);
- tfm = prev_tfm;
+ if (IS_ERR(tfm)) {
+ err = PTR_ERR(tfm);
+ goto out_unlock;
}
-done:
+ /* pairs with READ_ONCE() above */
+ smp_store_release(&tfms[mode_num], tfm);
+done_unlock:
ci->ci_ctfm = tfm;
- return 0;
+ err = 0;
+out_unlock:
+ mutex_unlock(&fscrypt_mode_key_setup_mutex);
+ return err;
}
int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
@@ -189,6 +198,43 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
return 0;
}
+static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci,
+ struct fscrypt_master_key *mk)
+{
+ int err;
+
+ err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_32_keys,
+ HKDF_CONTEXT_IV_INO_LBLK_32_KEY, true);
+ if (err)
+ return err;
+
+ /* pairs with smp_store_release() below */
+ if (!smp_load_acquire(&mk->mk_ino_hash_key_initialized)) {
+
+ mutex_lock(&fscrypt_mode_key_setup_mutex);
+
+ if (mk->mk_ino_hash_key_initialized)
+ goto unlock;
+
+ err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
+ HKDF_CONTEXT_INODE_HASH_KEY, NULL, 0,
+ (u8 *)&mk->mk_ino_hash_key,
+ sizeof(mk->mk_ino_hash_key));
+ if (err)
+ goto unlock;
+ /* pairs with smp_load_acquire() above */
+ smp_store_release(&mk->mk_ino_hash_key_initialized, true);
+unlock:
+ mutex_unlock(&fscrypt_mode_key_setup_mutex);
+ if (err)
+ return err;
+ }
+
+ ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,
+ &mk->mk_ino_hash_key);
+ return 0;
+}
+
static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
struct fscrypt_master_key *mk)
{
@@ -203,7 +249,7 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
* encryption key. This ensures that the master key is
* consistently used only for HKDF, avoiding key reuse issues.
*/
- err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_tfms,
+ err = setup_per_mode_enc_key(ci, mk, mk->mk_direct_keys,
HKDF_CONTEXT_DIRECT_KEY, false);
} else if (ci->ci_policy.v2.flags &
FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) {
@@ -211,11 +257,14 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
* IV_INO_LBLK_64: encryption keys are derived from (master_key,
* mode_num, filesystem_uuid), and inode number is included in
* the IVs. This format is optimized for use with inline
- * encryption hardware compliant with the UFS or eMMC standards.
+ * encryption hardware compliant with the UFS standard.
*/
- err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms,
+ err = setup_per_mode_enc_key(ci, mk, mk->mk_iv_ino_lblk_64_keys,
HKDF_CONTEXT_IV_INO_LBLK_64_KEY,
true);
+ } else if (ci->ci_policy.v2.flags &
+ FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) {
+ err = fscrypt_setup_iv_ino_lblk_32_key(ci, mk);
} else {
u8 derived_key[FSCRYPT_MAX_KEY_SIZE];
@@ -395,21 +444,18 @@ int fscrypt_get_encryption_info(struct inode *inode)
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
- if (!fscrypt_dummy_context_enabled(inode) ||
- IS_ENCRYPTED(inode)) {
+ const union fscrypt_context *dummy_ctx =
+ fscrypt_get_dummy_context(inode->i_sb);
+
+ if (IS_ENCRYPTED(inode) || !dummy_ctx) {
fscrypt_warn(inode,
"Error %d getting encryption context",
res);
return res;
}
/* Fake up a context for an unencrypted directory */
- memset(&ctx, 0, sizeof(ctx));
- ctx.version = FSCRYPT_CONTEXT_V1;
- ctx.v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
- ctx.v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
- memset(ctx.v1.master_key_descriptor, 0x42,
- FSCRYPT_KEY_DESCRIPTOR_SIZE);
- res = sizeof(ctx.v1);
+ res = fscrypt_context_size(dummy_ctx);
+ memcpy(&ctx, dummy_ctx, res);
}
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
@@ -475,7 +521,8 @@ out:
EXPORT_SYMBOL(fscrypt_get_encryption_info);
/**
- * fscrypt_put_encryption_info - free most of an inode's fscrypt data
+ * fscrypt_put_encryption_info() - free most of an inode's fscrypt data
+ * @inode: an inode being evicted
*
* Free the inode's fscrypt_info. Filesystems must call this when the inode is
* being evicted. An RCU grace period need not have elapsed yet.
@@ -488,7 +535,8 @@ void fscrypt_put_encryption_info(struct inode *inode)
EXPORT_SYMBOL(fscrypt_put_encryption_info);
/**
- * fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
+ * fscrypt_free_inode() - free an inode's fscrypt data requiring RCU delay
+ * @inode: an inode being freed
*
* Free the inode's cached decrypted symlink target, if any. Filesystems must
* call this after an RCU grace period, just before they free the inode.
@@ -503,7 +551,8 @@ void fscrypt_free_inode(struct inode *inode)
EXPORT_SYMBOL(fscrypt_free_inode);
/**
- * fscrypt_drop_inode - check whether the inode's master key has been removed
+ * fscrypt_drop_inode() - check whether the inode's master key has been removed
+ * @inode: an inode being considered for eviction
*
* Filesystems supporting fscrypt must call this from their ->drop_inode()
* method so that encrypted inodes are evicted as soon as they're no longer in
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.