FAILED: patch "[PATCH] ubifs: prevent creating duplicate encrypted filenames" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Dec 23, 2020

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Stable branch UBI file system (UBIFS)

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2020-12-23 14:16 UTC #0 lore raw

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 76786a0f083473de31678bdb259a3d4167cf756d Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Tue, 17 Nov 2020 23:56:08 -0800
Subject: [PATCH] ubifs: prevent creating duplicate encrypted filenames

As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key.

Fix this bug on ubifs by rejecting no-key dentries in ubifs_create(), ubifs_mkdir(), ubifs_mknod(), and ubifs_symlink().

Note that ubifs doesn't actually report the duplicate filenames from readdir, but rather it seems to replace the original dentry with a new one (which is still wrong, just a different effect from ext4).

On ubifs, this fixes xfstest generic/595 as well as the new xfstest I wrote specifically for this bug.

Fixes f4f61d2cc6d8 ("ubifs: Implement encrypted filenames")

Cc [email protected]

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Eric Biggers <[email protected]>

fs/ubifs/dir.c +13 -4

index 155521e51ac5..08fde777c324 100644
@@ -270,6 +270,15 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 	return d_splice_alias(inode, dentry);
 }
 
+static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry,
+				struct fscrypt_name *nm)
+{
+	if (fscrypt_is_nokey_name(dentry))
+		return -ENOKEY;
+
+	return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm);
+}
+
 static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 			bool excl)
 {

@@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	if (err)
 		return err;
 
-	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	err = ubifs_prepare_create(dir, dentry, &nm);
 	if (err)
 		goto out_budg;

@@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	if (err)
 		return err;
 
-	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	err = ubifs_prepare_create(dir, dentry, &nm);
 	if (err)
 		goto out_budg;

@@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
 		return err;
 	}
 
-	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	err = ubifs_prepare_create(dir, dentry, &nm);
 	if (err) {
 		kfree(dev);
 		goto out_budg;

@@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 	if (err)
 		return err;
 
-	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	err = ubifs_prepare_create(dir, dentry, &nm);
 	if (err)
 		goto out_budg;