From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B13F1A0B0E for ; Mon, 15 Jun 2026 03:22:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781493778; cv=none; b=I0eiRdOWIKY1QpphQ0lSFyL/1exvFGjuAlll+IUNCGMZhTWp8+HwJ+6Hmtj00VX4/+qbSOSb+ILXBTInH261tzNCItwYzDbkbc46IqtgJOod/+nUWZBjW8V7Obm3rnjO5WkCIESQFZ5ujhVJZGDU7J5ZpxQ6/ql/7zKZr8JA6kk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781493778; c=relaxed/simple; bh=PBELlYhzxOCPEd8pDtj++NcC2mWphz3wDmXKjJm1w0o=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=hiTUNyXATCgz8l1CBm98tusjQdTjMgyYjakNgd5JmfHK0jiYMPRRRzT5NP7ZTeO6B/ifxoyxEHwv0d1myz8oNyXptPtFELN/LWOSJyyNCU/CQucqXGZI3/9fPRWCgDIBu4bn25zmPTk38OY6mLfrB5ycdGMfhSPpeTsUdqERmz4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NaDH5e4F; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NaDH5e4F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BF2D1F000E9; Mon, 15 Jun 2026 03:22:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781493776; bh=SfPVj0aEgdaDeOEHqtnKRb087JFANu3x7EzZ4cr9AKk=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=NaDH5e4FHQlddFsxZi8k0Pgwu6CzFFH/eLFX4sMPEzlcWEUFpuVkkk5VPWgzVL6Kx aqYzx28JWTrLOImRZuycjP05hKlnC8DY9nUa38+WL/Ux1f5i5jv4qF847U1LsbgkX4 hoBFAv6UZUwUuZkiCzIw+LCdHWfVEKAsPJntMf4dwlX0ezEd4Gy7MMLEXjKpQdY5mI 5s59IVAfr+P3S64kqqzPyHoqvJzTXyWNeq+4ErVehBUMnomJLTFCI+s9HXuQ3t48Vj FY4mE1ROUp0kyPGUvTshvUPeBePml9KurjfaRcCVBxaYIbI33VAtU1No4d+JPoe0nR UD2hYUTdeG3FA== Message-ID: Date: Mon, 15 Jun 2026 11:22:53 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, zerocling0077@gmail.com, 2045gemini@gmail.com Subject: Re: [PATCH v2] f2fs: validate ACL entry sizes in f2fs_acl_from_disk() To: Zhang Cen , Jaegeuk Kim References: <20260613110526.1347194-1-rollkingzzc@gmail.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260613110526.1347194-1-rollkingzzc@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/13/26 19:05, Zhang Cen wrote: > f2fs_acl_count() only validates the aggregate ACL xattr length. A > malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only > contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk() > then reads entry->e_id before verifying that a full entry fits. > > Require a short entry before reading e_tag and e_perm, and require a > full entry before reading e_id for ACL_USER and ACL_GROUP. Return > -EFSCORRUPTED for malformed on-disk ACL blobs so corrupted ACL xattrs > are reported as filesystem corruption instead of generic invalid > arguments. > > Validation reproduced this kernel report: > KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0 > RIP: 0033:0x7f4b835ea7aa > The buggy address belongs to the object at ffff888114589960 which belongs > to the cache kmalloc-8 of size 8 > The buggy address is located 0 bytes to the right of allocated 8-byte > region [ffff888114589960, ffff888114589968) > Read of size 4 > Call trace: > dump_stack_lvl+0x66/0xa0 (?:?) > print_report+0xce/0x630 (?:?) > __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169) > srso_alias_return_thunk+0x5/0xfbef5 (?:?) > __virt_addr_valid+0x224/0x430 (?:?) > kasan_report+0xe0/0x110 (?:?) > __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169) > __get_acl+0x281/0x380 (?:?) > vfs_get_acl+0x10b/0x190 (?:?) > do_get_acl+0x2a/0x410 (?:?) > do_get_acl+0x9/0x410 (?:?) > do_getxattr+0xe8/0x260 (?:?) > filename_getxattr+0xd1/0x140 (?:?) > do_getname+0x2d/0x2d0 (?:?) > path_getxattrat+0x16c/0x200 (?:?) > lock_release+0xc8/0x290 (?:?) > cgroup_update_frozen+0x9d/0x320 (?:?) > lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?) > trace_hardirqs_on+0x1a/0x170 (?:?) > _raw_spin_unlock_irq+0x28/0x50 (?:?) > do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87) > entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) > > Fixes: af48b85b8cd3 ("f2fs: add xattr and acl functionalities") > > Assisted-by: Codex:gpt-5.5 > Signed-off-by: Zhang Cen > --- > Changes in v2: > - Wrap the new ACL entry-size checks in unlikely(). > - Return -EFSCORRUPTED for malformed on-disk ACL blobs. > > fs/f2fs/acl.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c > index fa8d81a30fb91..e62ce979be0b7 100644 > --- a/fs/f2fs/acl.c > +++ b/fs/f2fs/acl.c > @@ -53,14 +53,14 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) > const char *end = value + size; > > if (size < sizeof(struct f2fs_acl_header)) > - return ERR_PTR(-EINVAL); > + return ERR_PTR(-EFSCORRUPTED); The change is not related to this patch, right? I suspect you only give the hint to let LLM to replace EINVAL w/ EFSCORRUPTED in f2fs_acl_from_disk(), rather than replacing in newly added lines. > > if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION)) > - return ERR_PTR(-EINVAL); > + return ERR_PTR(-EFSCORRUPTED); Ditto, > > count = f2fs_acl_count(size); > if (count < 0) > - return ERR_PTR(-EINVAL); > + return ERR_PTR(-EFSCORRUPTED); Ditto, > if (count == 0) > return NULL; > > @@ -70,7 +70,8 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) > > for (i = 0; i < count; i++) { > > - if ((char *)entry > end) > + if (unlikely((char *)entry + > + sizeof(struct f2fs_acl_entry_short) > end)) > goto fail; > > acl->a_entries[i].e_tag = le16_to_cpu(entry->e_tag); > @@ -86,6 +87,9 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) > break; > > case ACL_USER: > + if (unlikely((char *)entry + > + sizeof(struct f2fs_acl_entry) > end)) > + goto fail; > acl->a_entries[i].e_uid = > make_kuid(&init_user_ns, > le32_to_cpu(entry->e_id)); > @@ -93,6 +97,9 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) > sizeof(struct f2fs_acl_entry)); > break; > case ACL_GROUP: > + if (unlikely((char *)entry + > + sizeof(struct f2fs_acl_entry) > end)) > + goto fail; > acl->a_entries[i].e_gid = > make_kgid(&init_user_ns, > le32_to_cpu(entry->e_id)); > @@ -108,7 +115,7 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) > return acl; > fail: > posix_acl_release(acl); > - return ERR_PTR(-EINVAL); > + return ERR_PTR(-EFSCORRUPTED); Ditto, Thanks, > } > > static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,