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 12FFE3A8724; Thu, 2 Jul 2026 16:28:43 +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=1783009725; cv=none; b=aF1f+8BSIa7OByy2rtDCgwFQSgurFOIclB98FHd1y7g+eR+rxjU+VBryRZ4BnPvQ//emMxJgCJavlkdUXpyVj1KyBgkHwh56cZpBK6VmgkD5DrfVsNrqMHl4M8lI2h1l7RubmHBqv0tAUiEUnEAeDU/xgegX15DgoSBmwBcCad8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783009725; c=relaxed/simple; bh=Sm3bJJp4ynCYbo4Aj8incrzcWZDAKXBBr6GqZB5RQzM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=edM3MWq2NQird2UfyFarnqGmK7178UZCgD9RgF54GXUSHCAS1VAUKwfxw19h7wDOb8frjkaCmd8LdVh8gJwUE5KDt2OKye+ufqEogz381/zhpBKF2rQvTuUfCqbAqeG5dAsxRT7LzGO8k9AnX4zEV4OaKPsuObYqnyL7vHn4WPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FDbZIb26; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FDbZIb26" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FB8D1F00A3A; Thu, 2 Jul 2026 16:28:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783009722; bh=nhneldcc9YWqLoFq4WwZ/WH1q5itqSjO5MuuVOsNe/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FDbZIb26SHa4lt1BZRibFZ848bmpd1lKXl7tbt3Y7ffP3U87eMhZ2wMeFX5Az4zyM DT+oBryujluY3uDWLAyBtgJxHZRvOLumBwQ+QFeHH9Iw4GTMGpMaTyfbPKaXdU6M5O JKZVI3D2Wdhzr40b5kNfEpa8rMJnVzAWrLADAaFo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Zhang Cen , Chao Yu , Jaegeuk Kim Subject: [PATCH 5.15 63/95] f2fs: validate ACL entry sizes in f2fs_acl_from_disk() Date: Thu, 2 Jul 2026 18:20:06 +0200 Message-ID: <20260702155110.537692786@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155109.196223802@linuxfoundation.org> References: <20260702155109.196223802@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Cen commit c4810ada31e80cbe4011467c4f3b1e93f94134f3 upstream. 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 from these new truncated-entry checks, while keeping the pre-existing -EINVAL paths unchanged. 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 (?:?) Cc: stable@kernel.org Fixes: af48b85b8cd3 ("f2fs: add xattr and acl functionalities") Assisted-by: Codex:gpt-5.5 Signed-off-by: Zhang Cen Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/acl.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -46,6 +46,7 @@ static inline int f2fs_acl_count(size_t static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) { int i, count; + int err = -EINVAL; struct posix_acl *acl; struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value; struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1); @@ -69,8 +70,11 @@ static struct posix_acl *f2fs_acl_from_d for (i = 0; i < count; i++) { - if ((char *)entry > end) + if (unlikely((char *)entry + + sizeof(struct f2fs_acl_entry_short) > end)) { + err = -EFSCORRUPTED; goto fail; + } acl->a_entries[i].e_tag = le16_to_cpu(entry->e_tag); acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm); @@ -85,6 +89,11 @@ static struct posix_acl *f2fs_acl_from_d break; case ACL_USER: + if (unlikely((char *)entry + + sizeof(struct f2fs_acl_entry) > end)) { + err = -EFSCORRUPTED; + goto fail; + } acl->a_entries[i].e_uid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); @@ -92,6 +101,11 @@ static struct posix_acl *f2fs_acl_from_d sizeof(struct f2fs_acl_entry)); break; case ACL_GROUP: + if (unlikely((char *)entry + + sizeof(struct f2fs_acl_entry) > end)) { + err = -EFSCORRUPTED; + goto fail; + } acl->a_entries[i].e_gid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); @@ -107,7 +121,7 @@ static struct posix_acl *f2fs_acl_from_d return acl; fail: posix_acl_release(acl); - return ERR_PTR(-EINVAL); + return ERR_PTR(err); } static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,