From nobody Thu Apr 2 17:24:23 2026 Received: from mail-oo1-f72.google.com (mail-oo1-f72.google.com [209.85.161.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25EF233065B for ; Sat, 21 Feb 2026 04:59:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.72 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771649974; cv=none; b=Abb9jQz5HlHV02ACj2TD1/IayclNi96+ANKpQ1EPM2spgESWfq4H8YhbcZf8IaOMIHwxPMEYTGzsfKYa1xKj51w9Tubn8YbrKiy5879YdRir40b5ZiGkpzrYDQ1f8umJAttEtElEhCHeCoJBzEVdz6zbcyrQOpgsT1RWlBSCt7U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771649974; c=relaxed/simple; bh=B2cXLhFpgRDJcUmF0bF0N6tSybZycgLKrjD5nR8WGMk=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=kqHTTL6TttgyoCoq3hW8ImBBKVKhp24slzLlS+m80CwF97wBkztrEwerXfw+l5ivekfpHKe37Omqgxoat/z/sHHd55J7yIdi8wxGHXA8KBc/RJQVRgti/vnt7tIAQA+dUJLTmH7pmUOy1yNSguE+mGmY1Jmd2PdavBz8V9iho1A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f72.google.com with SMTP id 006d021491bc7-6798747187eso43718933eaf.1 for ; Fri, 20 Feb 2026 20:59:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771649972; x=1772254772; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+fJ94H73MBDRemtwMn50UgdOy84zZMBOKR4UG4hi5fI=; b=wK+R6TXAdeVr71vFec1mc95B01CnuQBKRsxotn4UQPMLqR11bTwkRP1kDB0YPMWf7f buGbP3PaCjO9nlH2CzXNnn0s6zeJtXoHQ1CJmjJa0JZ/zVwkckDj8bCPOkSE4q5x2iKC C8NgUq99CCNxVvSNg3012ficHMAFUaPkVSnwL8Q0B1qj7OMCBzUgtZfz38uqtYntWqvj rUgYvxuJapmk1TF8mtb/kz+Ry3iuayZbqbgE20vsICwQxhkDBhS8y3wLvcaTRtODVg3H kaLldiRq25NFp3V4WN30Ti/nEx1SsRQ6oLmD4zSpMrg534i9ZUxT0FLNA0LzgK6Jr1W3 lRYg== X-Gm-Message-State: AOJu0YyBeM8E1yZ1nF6/kRipmEEGi9busppxsmIUag9cEyyxU6odNv3v pXM6Owe4TuWoBmyxULygJ3KkC9O81B+7R37UowvCr+f4kn7sGnhcRKa3BQsDXPiXCM1vEknoVFt SP3myC6IhULYlx5WfhmxpGM6pXhAuLdVz5ytuXM8I7x1FG7LyMqMQDT8HOoU= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4512:b0:663:13e9:d237 with SMTP id 006d021491bc7-679c4242287mr933816eaf.13.1771649971862; Fri, 20 Feb 2026 20:59:31 -0800 (PST) Date: Fri, 20 Feb 2026 20:59:31 -0800 In-Reply-To: <696ea368.a70a0220.34546f.04b7.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69993bb3.a70a0220.2c38d7.0151.GAE@google.com> Subject: Forwarded: [PATCH] hfsplus: fix uninit-value by validating catalog record size From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] hfsplus: fix uninit-value by validating catalog record size Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git= master Syzbot reported a KMSAN uninit-value issue in hfsplus_strcasecmp(). The root cause is that hfs_brec_read() doesn't validate that the on-disk record size matches the expected size for the record type being read. When mounting a corrupted filesystem, hfs_brec_read() may read less data than expected. For example, when reading a catalog thread record, the debug output showed: HFSPLUS_BREC_READ: rec_len=3D520, fd->entrylength=3D26 HFSPLUS_BREC_READ: WARNING - entrylength (26) < rec_len (520) - PARTIAL R= EAD! hfs_brec_read() only validates that entrylength is not greater than the buffer size, but doesn't check if it's less than expected. It successfully reads 26 bytes into a 520-byte structure and returns success, leaving 494 bytes uninitialized. This uninitialized data in tmp.thread.nodeName then gets copied by hfsplus_cat_build_key_uni() and used by hfsplus_strcasecmp(), triggering the KMSAN warning when the uninitialized bytes are used as array indices in case_fold(). Fix by introducing hfsplus_brec_read_cat() wrapper that: 1. Calls hfs_brec_read() to read the data 2. Validates the record size based on the type field: - Fixed size for folder and file records - Variable size for thread records (depends on string length) 3. Returns -EIO if size doesn't match expected For thread records, check minimum size before reading nodeName.length to avoid reading uninitialized data at call sites that don't zero-initialize the entry structure. Also initialize the tmp variable in hfsplus_find_cat() as defensive programming to ensure no uninitialized data even if validation is bypassed. Reported-by: syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3Dd80abb5b890d39261e72 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Tested-by: syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com Reviewed-by: Viacheslav Dubeyko Tested-by: Viacheslav Dubeyko Link: https://lore.kernel.org/all/20260120051114.1281285-1-kartikey406@gmai= l.com/ [v1] Link: https://lore.kernel.org/all/20260121063109.1830263-1-kartikey406@gmai= l.com/ [v2] Link: https://lore.kernel.org/all/20260212014233.2422046-1-kartikey406@gmai= l.com/ [v3] Link: https://lore.kernel.org/all/20260214002100.436125-1-kartikey406@gmail= .com/T/ [v4] Signed-off-by: Deepanshu Kartikey --- Changes in v5: - Add minimum size check for thread records before reading nodeName.length to avoid reading uninitialized data, as suggested by Charalampos Mitrodim= as Changes in v4: - Move hfsplus_cat_thread_size() as static inline to header file Changes in v3: - Introduced hfsplus_brec_read_cat() wrapper function for catalog-specific validation instead of modifying generic hfs_brec_read() - Added hfsplus_cat_thread_size() helper to calculate variable-size thread record sizes - Use exact size match (!=3D) instead of minimum size check (<) - Use sizeof(hfsplus_unichr) instead of hardcoded value 2 - Updated all catalog record read sites to use new wrapper function Changes in v2: - Use structure initialization (=3D {0}) instead of memset() - Improved commit message to clarify how uninitialized data is used --- fs/hfsplus/bfind.c | 52 +++++++++++++++++++++++++++++++++++++++++ fs/hfsplus/catalog.c | 4 ++-- fs/hfsplus/dir.c | 2 +- fs/hfsplus/hfsplus_fs.h | 9 +++++++ fs/hfsplus/super.c | 2 +- 5 files changed, 65 insertions(+), 4 deletions(-) diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c index 336d654861c5..2b9152c3107b 100644 --- a/fs/hfsplus/bfind.c +++ b/fs/hfsplus/bfind.c @@ -287,3 +287,55 @@ int hfs_brec_goto(struct hfs_find_data *fd, int cnt) fd->bnode =3D bnode; return res; } + +/** + * hfsplus_brec_read_cat - read and validate a catalog record + * @fd: find data structure + * @entry: pointer to catalog entry to read into + * + * Reads a catalog record and validates its size matches the expected + * size based on the record type. + * + * Returns 0 on success, or negative error code on failure. + */ +int hfsplus_brec_read_cat(struct hfs_find_data *fd, hfsplus_cat_entry *ent= ry) +{ + int res; + u32 expected_size; + + res =3D hfs_brec_read(fd, entry, sizeof(hfsplus_cat_entry)); + if (res) + return res; + + /* Validate catalog record size based on type */ + switch (be16_to_cpu(entry->type)) { + case HFSPLUS_FOLDER: + expected_size =3D sizeof(struct hfsplus_cat_folder); + break; + case HFSPLUS_FILE: + expected_size =3D sizeof(struct hfsplus_cat_file); + break; + case HFSPLUS_FOLDER_THREAD: + case HFSPLUS_FILE_THREAD: + /* Ensure we have at least the fixed fields before reading nodeName.leng= th */ + if (fd->entrylength < offsetof(struct hfsplus_cat_thread, nodeName) + + offsetof(struct hfsplus_unistr, unicode)) { + pr_err("thread record too short (got %u)\n", fd->entrylength); + return -EIO; + } + expected_size =3D hfsplus_cat_thread_size(&entry->thread); + break; + default: + pr_err("unknown catalog record type %d\n", + be16_to_cpu(entry->type)); + return -EIO; + } + + if (fd->entrylength !=3D expected_size) { + pr_err("catalog record size mismatch (type %d, got %u, expected %u)\n", + be16_to_cpu(entry->type), fd->entrylength, expected_size); + return -EIO; + } + + return 0; +} diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c index 02c1eee4a4b8..6c8380f7208d 100644 --- a/fs/hfsplus/catalog.c +++ b/fs/hfsplus/catalog.c @@ -194,12 +194,12 @@ static int hfsplus_fill_cat_thread(struct super_block= *sb, int hfsplus_find_cat(struct super_block *sb, u32 cnid, struct hfs_find_data *fd) { - hfsplus_cat_entry tmp; + hfsplus_cat_entry tmp =3D {0}; int err; u16 type; =20 hfsplus_cat_build_key_with_cnid(sb, fd->search_key, cnid); - err =3D hfs_brec_read(fd, &tmp, sizeof(hfsplus_cat_entry)); + err =3D hfsplus_brec_read_cat(fd, &tmp); if (err) return err; =20 diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c index ca5f74a140ec..8aeb861969d3 100644 --- a/fs/hfsplus/dir.c +++ b/fs/hfsplus/dir.c @@ -49,7 +49,7 @@ static struct dentry *hfsplus_lookup(struct inode *dir, s= truct dentry *dentry, if (unlikely(err < 0)) goto fail; again: - err =3D hfs_brec_read(&fd, &entry, sizeof(entry)); + err =3D hfsplus_brec_read_cat(&fd, &entry); if (err) { if (err =3D=3D -ENOENT) { hfs_find_exit(&fd); diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h index 5f891b73a646..61d52091dd28 100644 --- a/fs/hfsplus/hfsplus_fs.h +++ b/fs/hfsplus/hfsplus_fs.h @@ -509,6 +509,15 @@ int hfsplus_submit_bio(struct super_block *sb, sector_= t sector, void *buf, void **data, blk_opf_t opf); int hfsplus_read_wrapper(struct super_block *sb); =20 +static inline u32 hfsplus_cat_thread_size(const struct hfsplus_cat_thread = *thread) +{ + return offsetof(struct hfsplus_cat_thread, nodeName) + + offsetof(struct hfsplus_unistr, unicode) + + be16_to_cpu(thread->nodeName.length) * sizeof(hfsplus_unichr); +} + +int hfsplus_brec_read_cat(struct hfs_find_data *fd, hfsplus_cat_entry *ent= ry); + /* * time helpers: convert between 1904-base and 1970-base timestamps * diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c index 592d8fbb748c..dcb4357aae3e 100644 --- a/fs/hfsplus/super.c +++ b/fs/hfsplus/super.c @@ -571,7 +571,7 @@ static int hfsplus_fill_super(struct super_block *sb, s= truct fs_context *fc) err =3D hfsplus_cat_build_key(sb, fd.search_key, HFSPLUS_ROOT_CNID, &str); if (unlikely(err < 0)) goto out_put_root; - if (!hfs_brec_read(&fd, &entry, sizeof(entry))) { + if (!hfsplus_brec_read_cat(&fd, &entry)) { hfs_find_exit(&fd); if (entry.type !=3D cpu_to_be16(HFSPLUS_FOLDER)) { err =3D -EIO; --=20 2.43.0