Re: Patch "ubifs: report correct st_size for encrypted symlinks" has been added to the 5.4-stable tree

Re: Patch "ubifs: report correct st_size for encrypted symlinks" has been added to the 5.4-stable tree

[Greg KH]

On Wed, Sep 01, 2021 at 12:52:47PM +0200, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     ubifs: report correct st_size for encrypted symlinks
> 
> to the 5.4-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

Breaks the build, now dropping.

Patch "ubifs: report correct st_size for encrypted symlinks" has been added to the 5.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ubifs: report correct st_size for encrypted symlinks

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ubifs-report-correct-st_size-for-encrypted-symlinks.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From foo@baz Fri Sep  3 03:56:23 PM CEST 2021
From: Eric Biggers <ebiggers@kernel.org>
Date: Wed,  1 Sep 2021 09:40:41 -0700
Subject: ubifs: report correct st_size for encrypted symlinks
To: stable@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org
Message-ID: <20210901164041.176238-5-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

commit 064c734986011390b4d111f1a99372b7f26c3850 upstream.

The stat() family of syscalls report the wrong size for encrypted
symlinks, which has caused breakage in several userspace programs.

Fix this by calling fscrypt_symlink_getattr() after ubifs_getattr() for
encrypted symlinks.  This function computes the correct size by reading
and decrypting the symlink target (if it's not already cached).

For more details, see the commit which added fscrypt_symlink_getattr().

Fixes: ca7f85be8d6c ("ubifs: Add support for encrypted symlinks")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210702065350.209646-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/ubifs/file.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1629,6 +1629,16 @@ static const char *ubifs_get_link(struct
 	return fscrypt_get_symlink(inode, ui->data, ui->data_len, done);
 }
 
+static int ubifs_symlink_getattr(const struct path *path, struct kstat *stat,
+				 u32 request_mask, unsigned int query_flags)
+{
+	ubifs_getattr(path, stat, request_mask, query_flags);
+
+	if (IS_ENCRYPTED(d_inode(path->dentry)))
+		return fscrypt_symlink_getattr(path, stat);
+	return 0;
+}
+
 const struct address_space_operations ubifs_file_address_operations = {
 	.readpage       = ubifs_readpage,
 	.writepage      = ubifs_writepage,
@@ -1654,7 +1664,7 @@ const struct inode_operations ubifs_file
 const struct inode_operations ubifs_symlink_inode_operations = {
 	.get_link    = ubifs_get_link,
 	.setattr     = ubifs_setattr,
-	.getattr     = ubifs_getattr,
+	.getattr     = ubifs_symlink_getattr,
 #ifdef CONFIG_UBIFS_FS_XATTR
 	.listxattr   = ubifs_listxattr,
 #endif


Patches currently in stable-queue which might be from ebiggers@kernel.org are

queue-5.4/ubifs-report-correct-st_size-for-encrypted-symlinks.patch
queue-5.4/ext4-report-correct-st_size-for-encrypted-symlinks.patch
queue-5.4/fscrypt-add-fscrypt_symlink_getattr-for-computing-st_size.patch
queue-5.4/f2fs-report-correct-st_size-for-encrypted-symlinks.patch

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