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 4977743B6E7; Mon, 17 Aug 2026 14:49:26 +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=1786978174; cv=none; b=NuGHfF708DmLuHvg5I7BZCuARSvIEP++eo/3lE08u6aHxcmYpGRuyhFpif6jflzUSQwG2tBwFacuu1mzoGFQBH07+Is32G6RBZnwtb8oqjWfrM85fmuBPn1EAxq0sl28mQO/TCnW3OmXc0EpOeH2Ix1RVYWYkUbi5ofhQWZEkHA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978174; c=relaxed/simple; bh=hmXPTqNO/B6mZYjh752XM52CK79/S+6mXbhUemfmw7c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i/il9tmN1PtsUwknPPXyxggqvFI0OAa0IZSYNU5pATiq33RunbZGcCqwwdz0FlyJ4aqrTsBVxmnJzmO6X1OVTfmAIA/EsnlystfsBQ3O25QoKU4hxP36KwRCz+glO0hJBnREALwCH/EbhBeV4gCmWkl0/QeTK5frdksuzEwtUps= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=shXflcO1; 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="shXflcO1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E93A21F00A3D; Mon, 17 Aug 2026 14:49:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786978165; bh=/CfJBX6T8D97pZ9Q7VoByexHroIIVG94BlU9qo6ojZk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=shXflcO1IqI9gJnuzboyUKJ76XnubtDXHXpiV07GzyuIDnKZQWgxOUmumv2ynUFkM xO977ujlWD2MJUpKwQPl8Qn4U/46eXJj/tp5CDnGltSgdQSNHIEKh0QeY70aiP0AzG fGEhQIHhAH0WoSOlSBFSvClYlI/Hf4X1p2EaSEPU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lincoln Wallace , Mimi Zohar Subject: [PATCH 6.12 085/181] ima: fix out-of-bounds read in xattr_verify() Date: Mon, 17 Aug 2026 15:32:59 +0200 Message-ID: <20260817132538.789181021@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132535.394764707@linuxfoundation.org> References: <20260817132535.394764707@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: Lincoln Wallace commit 5ff232d31106f45ac87c3b64e1d35a0667777797 upstream. The digest-length check in xattr_verify() mixes int and size_t: if (xattr_len - sizeof(xattr_value->type) - hash_start >= iint->ima_hash->length) sizeof() yields size_t, so the usual arithmetic conversions promote the whole left-hand side to unsigned 64-bit before the subtraction runs. For a truncated xattr this underflows instead of going negative: a 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1) turns "1 - 1 - 1" into SIZE_MAX, which is trivially >= ima_hash->length. The check then passes and the following memcmp() reads iint->ima_hash->length bytes starting past the end of the buffer vfs_getxattr_alloc() allocated for it. Nothing upstream clamps xattr_len back into a safe range first: ima_get_hash_algo() only special-cases xattr_len < 2 to pick a default algorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than failing when no HMAC key is loaded, so a truncated security.ima value reaches the length check as-is. Rewrite the comparison so every operand stays a signed int and no implicit conversion to size_t can occur. Fixes: 3ea7a56067e6 ("ima: provide hash algo info in the xattr") Cc: stable@vger.kernel.org Signed-off-by: Lincoln Wallace Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman --- security/integrity/ima/ima_appraise.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -302,8 +302,13 @@ static int xattr_verify(enum ima_hooks f } else { set_bit(IMA_DIGSIG, &iint->atomic_flags); } - if (xattr_len - sizeof(xattr_value->type) - hash_start >= - iint->ima_hash->length) + /* + * Use addition, not subtraction: sizeof() forces unsigned + * math and a short xattr_len would wrap around, bypassing + * this bounds check. + */ + if (xattr_len >= (int)sizeof(xattr_value->type) + hash_start + + (int)iint->ima_hash->length) /* * xattr length may be longer. md5 hash in previous * version occupied 20 bytes in xattr, instead of 16