From: Gabriel Krisman Bertazi <krisman@suse.de>
To: ebiggers@kernel.org, viro@zeniv.linux.org.uk
Cc: Gabriel Krisman Bertazi <krisman@suse.de>,
brauner@kernel.org, tytso@mit.edu, amir73il@gmail.com,
linux-f2fs-devel@lists.sourceforge.net,
linux-fsdevel@vger.kernel.org, jaegeuk@kernel.org,
linux-ext4@vger.kernel.org
Subject: [f2fs-dev] [PATCH v6 01/10] ovl: Always reject mounting over case-insensitive directories
Date: Mon, 12 Feb 2024 21:13:12 -0500 [thread overview]
Message-ID: <20240213021321.1804-2-krisman@suse.de> (raw)
In-Reply-To: <20240213021321.1804-1-krisman@suse.de>
overlayfs relies on the filesystem setting DCACHE_OP_HASH or
DCACHE_OP_COMPARE to reject mounting over case-insensitive directories.
Since commit bb9cd9106b22 ("fscrypt: Have filesystems handle their
d_ops"), we set ->d_op through a hook in ->d_lookup, which
means the root dentry won't have them, causing the mount to accidentally
succeed.
In v6.7-rc7, the following sequence will succeed to mount, but any
dentry other than the root dentry will be a "weird" dentry to ovl and
fail with EREMOTE.
mkfs.ext4 -O casefold lower.img
mount -O loop lower.img lower
mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl /mnt
Mounting on a subdirectory fails, as expected, because DCACHE_OP_HASH
and DCACHE_OP_COMPARE are properly set by ->lookup.
Fix by explicitly rejecting superblocks that allow case-insensitive
dentries. Yes, this will be solved when we move d_op configuration back
to ->s_d_op. Yet, we better have an explicit fix to avoid messing up
again.
While there, re-sort the entries to have more descriptive error messages
first.
Fixes: bb9cd9106b22 ("fscrypt: Have filesystems handle their d_ops")
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Acked-by: Amir Goldstein <amir73il@gmail.com>
---
changes since v5:
- summary line again (eric)
changes since v3:
- Case insensitive filesystem ->Case insensitive capable
filesystem (eric)
- clarify patch summary line
changes since v2:
- Re-sort checks to trigger more descriptive error messages
first (Amir)
- Add code comment (Amir)
---
fs/overlayfs/params.c | 14 +++++++++++---
include/linux/fs.h | 9 +++++++++
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 3fe2dde1598f..488f920f79d2 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -280,12 +280,20 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
{
struct ovl_fs_context *ctx = fc->fs_private;
- if (ovl_dentry_weird(path->dentry))
- return invalfc(fc, "filesystem on %s not supported", name);
-
if (!d_is_dir(path->dentry))
return invalfc(fc, "%s is not a directory", name);
+ /*
+ * Root dentries of case-insensitive capable filesystems might
+ * not have the dentry operations set, but still be incompatible
+ * with overlayfs. Check explicitly to prevent post-mount
+ * failures.
+ */
+ if (sb_has_encoding(path->mnt->mnt_sb))
+ return invalfc(fc, "case-insensitive capable filesystem on %s not supported", name);
+
+ if (ovl_dentry_weird(path->dentry))
+ return invalfc(fc, "filesystem on %s not supported", name);
/*
* Check whether upper path is read-only here to report failures
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98b7a7a8c42e..e6667ece5e64 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3203,6 +3203,15 @@ extern int generic_check_addressable(unsigned, u64);
extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
+static inline bool sb_has_encoding(const struct super_block *sb)
+{
+#if IS_ENABLED(CONFIG_UNICODE)
+ return !!sb->s_encoding;
+#else
+ return false;
+#endif
+}
+
int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
unsigned int ia_valid);
int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
--
2.43.0
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2024-02-13 2:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 2:13 [f2fs-dev] [PATCH v6 00/10] Set casefold/fscrypt dentry operations through sb->s_d_op Gabriel Krisman Bertazi
2024-02-13 2:13 ` Gabriel Krisman Bertazi [this message]
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 02/10] fscrypt: Factor out a helper to configure the lookup dentry Gabriel Krisman Bertazi
2024-02-14 23:54 ` Eric Biggers
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 03/10] fscrypt: Drop d_revalidate for valid dentries during lookup Gabriel Krisman Bertazi
2024-02-14 23:59 ` Eric Biggers
2024-02-20 23:03 ` Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 04/10] fscrypt: Drop d_revalidate once the key is added Gabriel Krisman Bertazi
2024-02-15 0:16 ` Eric Biggers
2024-02-15 0:31 ` Eric Biggers
2024-02-20 0:48 ` Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 05/10] libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 06/10] libfs: Add helper to choose dentry operations at mount-time Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 07/10] ext4: Configure dentry operations at dentry-creation time Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 08/10] f2fs: " Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 09/10] ubifs: " Gabriel Krisman Bertazi
2024-02-13 2:13 ` [f2fs-dev] [PATCH v6 10/10] libfs: Drop generic_set_encrypted_ci_d_ops Gabriel Krisman Bertazi
2024-02-15 0:24 ` [f2fs-dev] [PATCH v6 00/10] Set casefold/fscrypt dentry operations through sb->s_d_op Eric Biggers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240213021321.1804-2-krisman@suse.de \
--to=krisman@suse.de \
--cc=amir73il@gmail.com \
--cc=brauner@kernel.org \
--cc=ebiggers@kernel.org \
--cc=jaegeuk@kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-f2fs-devel@lists.sourceforge.net \
--cc=linux-fsdevel@vger.kernel.org \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).