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 1620937E5C4; Sat, 12 Sep 2026 10:10:44 +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=1789207845; cv=none; b=I40twFlzuJ8Fiz0GVSnrjzy+idHmb0V/gRkAkA/gREaY6gQceQ1YQGZ06+36jwun6cv/AjbhSF8v1TXRej34RJOTiQpI2ccvovPxiRnbTyHG9j+VW9JW3XPWXRHz4NVEDGe9n873BIqvydvnONGfYD8dd2A1Z78GDLJzejpFKj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789207845; c=relaxed/simple; bh=IMbnV24tgcoHUIQa1Y/B+9Kr6yCHv0LPRz1IzbtsNnk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OahXu9APV+0+41VRaaYfb17IbKbhQBLLUuT87O1DM1hg0mhBZNPAoLlY8tavV+v3lpak84aTokQy/IiF3YgB6x4JLEjfamz6+BusL8zNiRJhaRE0rVRl76hPN5h33BoBb4LrwuTUM8+qnMQiLSvaD0JZdSabJjkCiAM6vkKKJhA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kIsZaq+2; 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="kIsZaq+2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E93171F00893; Sat, 12 Sep 2026 10:10:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789207843; bh=sib8YWYvmftdaDKmlXl5ELL2KMWCONHphhMrMRHVkR4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kIsZaq+2wTwcY2q3Fi+D1rVNuYTFCvKsrDNHL8YzbxSIY01dL/OwtF8DdIeCrTiOz Amn2q3cfdQt8FFfB1dDj3QAE06kVC/WkFz/se7fgpStq6wdyDjWoscaT9sTD0iWlPZ N1EcRa0WWG/rAr56TAliIFKqeckb9zur3JObQ8+M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Jan Kara , Theodore Tso , Sasha Levin Subject: [PATCH 6.18 0495/1518] ext4: fix out-of-bounds read in ext4_read_inline_dir() Date: Sat, 12 Sep 2026 08:44:24 +0200 Message-ID: <20260912065634.643979006@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 9333cc809f0a89e001b814155a6cb8903a6274df ] ext4_read_inline_dir() can read a dirent header past the end of its inline buffer, triggering a slab-out-of-bounds read during getdents64(): BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry Read of size 2 at addr ffff88800f3dd23c by task exploit/148 ... __ext4_check_dir_entry ext4_read_inline_dir iterate_dir The dirent payload lives in a buffer of exactly inline_size bytes: dir_buf = kmalloc(inline_size, GFP_NOFS); but iteration runs in a position space extra_offset bytes larger (extra_size = extra_offset + inline_size) so the synthetic "." and ".." land at their block-dir offsets. A dirent is formed at "dir_buf + pos - extra_offset", yet the ext4_check_dir_entry() length argument uses the larger extra_size. A position whose dirent header would extend past extra_size is therefore accepted, and the rescan loop's rec_len probe and ext4_check_dir_entry() dereference de->rec_len before the entry is rejected. Reject a position whose minimum-size dirent header would not fit within extra_size before forming de, in both the rescan and main loops, and pass inline_size rather than extra_size to ext4_check_dir_entry() so the length check matches the physical buffer. Fixes: c4d8b0235aa9 ("ext4: fix readdir error in case inline_data+^dir_index.") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260615190519.946736-1-xmei5@asu.edu Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/inline.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index 408677fa81967..1a48ccaa364dc 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -1454,6 +1454,8 @@ int ext4_read_inline_dir(struct file *file, /* for other entry, the real offset in * the buf has to be tuned accordingly. */ + if (i + ext4_dir_rec_len(1, NULL) > extra_size) + break; de = (struct ext4_dir_entry_2 *) (dir_buf + i - extra_offset); /* It's too expensive to do a full @@ -1488,10 +1490,17 @@ int ext4_read_inline_dir(struct file *file, continue; } + /* + * de lives at dir_buf + ctx->pos - extra_offset, within the + * kmalloc(inline_size) buffer. Make sure its header fits before + * ext4_check_dir_entry() dereferences de->rec_len. + */ + if (ctx->pos + ext4_dir_rec_len(1, NULL) > extra_size) + goto out; de = (struct ext4_dir_entry_2 *) (dir_buf + ctx->pos - extra_offset); if (ext4_check_dir_entry(inode, file, de, iloc.bh, dir_buf, - extra_size, ctx->pos)) + inline_size, ctx->pos)) goto out; if (le32_to_cpu(de->inode)) { if (!dir_emit(ctx, de->name, de->name_len, -- 2.53.0