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 4C6932D0C75; Sat, 12 Sep 2026 12:24:18 +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=1789215859; cv=none; b=YvhcHg6Sz+N8WoUdLbdAl74F24c/f+8DQovnRtP0WppNuwmq43TAARxf7rSilitOk+rd9aIxQkR58RcI9/hMj64Fx/qH0/a8/OZ/8SGlsFN08+qWQp9Pj9I3+/7ie3d79q3gkzTU+nLsmRCoVty63niJHQeCDrRvBrKtnoHQibA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789215859; c=relaxed/simple; bh=CYSwGSAJ8OE80Og8/1RUv/pcN682lR8U4RAl1IXSDHw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XfvSzVWwv1AQgnRLLaK48pRDReObOx3zjK4H3Zm0axLOMkXJ/9g5RMhaJleoB8x38VJTkwIWwoPh0P17ouec7/xbzF8fcIg06yBv+CW4Vsu0ygKL31OuX3NburFSMKWmi/+GWpp/bJNO4vLzk6rPZR5Ch1Rr2uzvuun8zU4djf4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=W3w5MSO5; 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="W3w5MSO5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 058741F000FF; Sat, 12 Sep 2026 12:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789215858; bh=XOekfUJ6T+6VBDT/8JSMFkuxR7y7HyEftBRvLOcqdxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=W3w5MSO5P1GDDn1aQX9c3arhe3dMxjcH0xWQ/ZPuvVyI0+fC5jyJEanwXHdxyhi3O hX2wfAKXubnL8+bY9zmOC9SeUY335ZKCczEFxH9cbQ21o6H3NgX6Ul4vPQqprF2YTT s2QefURSuyWU7ppgHuavCpSujK2PQxTcXwZYmXNg= 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 6.12 0619/1376] ext4: fix out-of-bounds read in ext4_read_inline_dir() Date: Sat, 12 Sep 2026 08:50:45 +0200 Message-ID: <20260912065621.338123481@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@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 6.12-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 b55bf19c82f26..54eb10c376379 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -1554,6 +1554,8 @@ 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 @@ -1588,10 +1590,17 @@ 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