From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	stable@kernel.org,
	Wenjie Qi <qiwenjie@xiaomi.com>,
	Chao Yu <chao@kernel.org>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18 1174/1250] f2fs: limit recovery filename logging to stored length
Date: Thu, 17 Sep 2026 16:16:09 +0100
Message-ID: <20260917151624.107217142@linuxfoundation.org>
In-Reply-To: <20260917151551.901433442@linuxfoundation.org>
References: <20260917151551.901433442@linuxfoundation.org>
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6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wenjie Qi <qwjhust@gmail.com>

[ Upstream commit 01027b2fcb74dade59fb833b51023f6593b6a9a2 ]

F2FS stores recovery filenames as a length plus a fixed-size i_name
buffer.  The buffer is not NUL-terminated, but recover_inode() and
recover_dentry() print it with %s.

For a 255-byte filename, recovery logging can read past i_name into the
following raw inode fields.

Print the name with a precision bounded by i_namelen and F2FS_NAME_LEN.

Fixes: f356fe0cba0e ("f2fs: add debug msgs in the recovery routine")
Cc: stable@kernel.org
Assisted-by: Codex:gpt-5.5
Signed-off-by: Wenjie Qi <qiwenjie@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
[ Retained %lx instead of %llu for the branch’s unsigned long directory inode numbers. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/f2fs/recovery.c |   33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -169,7 +169,8 @@ static int recover_dentry(struct inode *
 	struct inode *dir, *einode;
 	struct fsync_inode_entry *entry;
 	int err = 0;
-	char *name;
+	const char *name;
+	int name_len;
 
 	entry = get_fsync_inode(dir_list, pino);
 	if (!entry) {
@@ -228,12 +229,16 @@ retry:
 out_put:
 	f2fs_folio_put(folio, false);
 out:
-	if (file_enc_name(inode))
+	if (file_enc_name(inode)) {
 		name = "<encrypted>";
-	else
+		name_len = sizeof("<encrypted>") - 1;
+	} else {
 		name = raw_inode->i_name;
-	f2fs_notice(F2FS_I_SB(inode), "%s: ino = %x, name = %s, dir = %lx, err = %d",
-		    __func__, ino_of_node(ifolio), name,
+		name_len = min_t(unsigned int, le32_to_cpu(raw_inode->i_namelen),
+				 F2FS_NAME_LEN);
+	}
+	f2fs_notice(F2FS_I_SB(inode), "%s: ino = %x, name = %.*s, dir = %lx, err = %d",
+		    __func__, ino_of_node(ifolio), name_len, name,
 		    IS_ERR(dir) ? 0 : dir->i_ino, err);
 	return err;
 }
@@ -281,7 +286,8 @@ static int recover_inode(struct inode *i
 {
 	struct f2fs_inode *raw = F2FS_INODE(folio);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
-	char *name;
+	const char *name;
+	int name_len;
 	int err;
 
 	inode->i_mode = le16_to_cpu(raw->i_mode);
@@ -330,13 +336,18 @@ static int recover_inode(struct inode *i
 
 	f2fs_mark_inode_dirty_sync(inode, true);
 
-	if (file_enc_name(inode))
+	if (file_enc_name(inode)) {
 		name = "<encrypted>";
-	else
-		name = F2FS_INODE(folio)->i_name;
+		name_len = sizeof("<encrypted>") - 1;
+	} else {
+		name = raw->i_name;
+		name_len = min_t(unsigned int, le32_to_cpu(raw->i_namelen),
+				 F2FS_NAME_LEN);
+	}
 
-	f2fs_notice(F2FS_I_SB(inode), "recover_inode: ino = %x, name = %s, inline = %x",
-		    ino_of_node(folio), name, raw->i_inline);
+	f2fs_notice(F2FS_I_SB(inode), "%s: ino = %x, name = %.*s, inline = %x",
+		    __func__, ino_of_node(folio), name_len, name,
+		    raw->i_inline);
 	return 0;
 }