Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 3da3707..891328f 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -273,13 +273,8 @@
 					   oname->name);
 		return 0;
 	}
-	if (hash) {
-		digested_name.hash = hash;
-		digested_name.minor_hash = minor_hash;
-	} else {
-		digested_name.hash = 0;
-		digested_name.minor_hash = 0;
-	}
+	digested_name.hash = hash;
+	digested_name.minor_hash = minor_hash;
 	memcpy(digested_name.digest,
 	       FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
 	       FSCRYPT_FNAME_DIGEST_SIZE);
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index e84efc0..ec73872 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -23,6 +23,9 @@
 #define FSCRYPT_CONTEXT_V1	1
 #define FSCRYPT_CONTEXT_V2	2
 
+/* Keep this in sync with include/uapi/linux/fscrypt.h */
+#define FSCRYPT_MODE_MAX	FSCRYPT_MODE_ADIANTUM
+
 struct fscrypt_context_v1 {
 	u8 version; /* FSCRYPT_CONTEXT_V1 */
 	u8 contents_encryption_mode;
@@ -387,7 +390,7 @@
 	spinlock_t		mk_decrypted_inodes_lock;
 
 	/* Per-mode tfms for DIRECT_KEY policies, allocated on-demand */
-	struct crypto_skcipher	*mk_mode_keys[__FSCRYPT_MODE_MAX + 1];
+	struct crypto_skcipher	*mk_mode_keys[FSCRYPT_MODE_MAX + 1];
 
 } __randomize_layout;
 
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
index bb3b7fc..82575cf 100644
--- a/fs/crypto/hooks.c
+++ b/fs/crypto/hooks.c
@@ -58,8 +58,8 @@
 	if (err)
 		return err;
 
-	/* ... in case we looked up ciphertext name before key was added */
-	if (dentry->d_flags & DCACHE_ENCRYPTED_NAME)
+	/* ... in case we looked up no-key name before key was added */
+	if (fscrypt_is_nokey_name(dentry))
 		return -ENOKEY;
 
 	if (!fscrypt_has_permitted_context(dir, inode))
@@ -83,9 +83,9 @@
 	if (err)
 		return err;
 
-	/* ... in case we looked up ciphertext name(s) before key was added */
-	if ((old_dentry->d_flags | new_dentry->d_flags) &
-	    DCACHE_ENCRYPTED_NAME)
+	/* ... in case we looked up no-key name(s) before key was added */
+	if (fscrypt_is_nokey_name(old_dentry) ||
+	    fscrypt_is_nokey_name(new_dentry))
 		return -ENOKEY;
 
 	if (old_dir != new_dir) {
@@ -305,3 +305,47 @@
 	return ERR_PTR(err);
 }
 EXPORT_SYMBOL_GPL(fscrypt_get_symlink);
+
+/**
+ * fscrypt_symlink_getattr() - set the correct st_size for encrypted symlinks
+ * @path: the path for the encrypted symlink being queried
+ * @stat: the struct being filled with the symlink's attributes
+ *
+ * Override st_size of encrypted symlinks to be the length of the decrypted
+ * symlink target (or the no-key encoded symlink target, if the key is
+ * unavailable) rather than the length of the encrypted symlink target.  This is
+ * necessary for st_size to match the symlink target that userspace actually
+ * sees.  POSIX requires this, and some userspace programs depend on it.
+ *
+ * This requires reading the symlink target from disk if needed, setting up the
+ * inode's encryption key if possible, and then decrypting or encoding the
+ * symlink target.  This makes lstat() more heavyweight than is normally the
+ * case.  However, decrypted symlink targets will be cached in ->i_link, so
+ * usually the symlink won't have to be read and decrypted again later if/when
+ * it is actually followed, readlink() is called, or lstat() is called again.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat)
+{
+	struct dentry *dentry = path->dentry;
+	struct inode *inode = d_inode(dentry);
+	const char *link;
+	DEFINE_DELAYED_CALL(done);
+
+	/*
+	 * To get the symlink target that userspace will see (whether it's the
+	 * decrypted target or the no-key encoded target), we can just get it in
+	 * the same way the VFS does during path resolution and readlink().
+	 */
+	link = READ_ONCE(inode->i_link);
+	if (!link) {
+		link = inode->i_op->get_link(dentry, inode, &done);
+		if (IS_ERR(link))
+			return PTR_ERR(link);
+	}
+	stat->size = strlen(link);
+	do_delayed_call(&done);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fscrypt_symlink_getattr);
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index c34fa7c..4ee65b2 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -664,9 +664,6 @@
 	struct list_head *pos;
 	size_t busy_count = 0;
 	unsigned long ino;
-	struct dentry *dentry;
-	char _path[256];
-	char *path = NULL;
 
 	spin_lock(&mk->mk_decrypted_inodes_lock);
 
@@ -685,22 +682,14 @@
 					 struct fscrypt_info,
 					 ci_master_key_link)->ci_inode;
 		ino = inode->i_ino;
-		dentry = d_find_alias(inode);
 	}
 	spin_unlock(&mk->mk_decrypted_inodes_lock);
 
-	if (dentry) {
-		path = dentry_path(dentry, _path, sizeof(_path));
-		dput(dentry);
-	}
-	if (IS_ERR_OR_NULL(path))
-		path = "(unknown)";
-
 	fscrypt_warn(NULL,
-		     "%s: %zu inode(s) still busy after removing key with %s %*phN, including ino %lu (%s)",
+		     "%s: %zu inode(s) still busy after removing key with %s %*phN, including ino %lu",
 		     sb->s_id, busy_count, master_key_spec_type(&mk->mk_spec),
 		     master_key_spec_len(&mk->mk_spec), (u8 *)&mk->mk_spec.u,
-		     ino, path);
+		     ino);
 	return -EBUSY;
 }
 
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index d71c2d6..3e86f75 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -55,6 +55,8 @@
 select_encryption_mode(const union fscrypt_policy *policy,
 		       const struct inode *inode)
 {
+	BUILD_BUG_ON(ARRAY_SIZE(available_modes) != FSCRYPT_MODE_MAX + 1);
+
 	if (S_ISREG(inode->i_mode))
 		return &available_modes[fscrypt_policy_contents_mode(policy)];
 
@@ -579,6 +581,15 @@
 	mk = ci->ci_master_key->payload.data[0];
 
 	/*
+	 * With proper, non-racy use of FS_IOC_REMOVE_ENCRYPTION_KEY, all inodes
+	 * protected by the key were cleaned by sync_filesystem().  But if
+	 * userspace is still using the files, inodes can be dirtied between
+	 * then and now.  We mustn't lose any writes, so skip dirty inodes here.
+	 */
+	if (inode->i_state & I_DIRTY_ALL)
+		return 0;
+
+	/*
 	 * Note: since we aren't holding ->mk_secret_sem, the result here can
 	 * immediately become outdated.  But there's no correctness problem with
 	 * unnecessarily evicting.  Nor is there a correctness problem with not
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 4072ba6..8e1b108 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -55,7 +55,8 @@
 			return false;
 		}
 
-		if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+		if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
+				      FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
 			fscrypt_warn(inode,
 				     "Unsupported encryption flags (0x%02x)",
 				     policy->flags);
@@ -76,7 +77,8 @@
 			return false;
 		}
 
-		if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
+		if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
+				      FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
 			fscrypt_warn(inode,
 				     "Unsupported encryption flags (0x%02x)",
 				     policy->flags);