From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 79F711E22FC for ; Mon, 20 Jan 2025 13:49:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737380952; cv=none; b=cEFLV0jhUn9ArrEkMK5koHP7muX1eaj+cuETB86l/FCxM+BwSiIqLhYoQwCOFJ5izZy4dJjQBVeDcgxdAamFwEpogligrG2K3VUcUBpOwBNXXGO39n7545ZR8LofCuy8WE/5uNSLBFMyeelxEDeX7tKRFliUHRuqYPAuCAdF8hM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737380952; c=relaxed/simple; bh=SVKVeCFZ4IiFQlohbcREUsgS7z9cGGnFhFBRjQAMfJ4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tzsldL56pLorlpC4u41PtV9FDgUm/XgNY9KnpNc8YrFsqObPy/AuAWUnzyf2jDQgC9IfXikydBCz3Z0i5KownKpBVRyCzmToQrCfkKylBBLsOu7Rt/GJeyde/R4pA+ZD5cKKkNNI2I0haZeOqJE5EAwKeNsOAa7n73CXWGZRImQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iq7t7Epd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iq7t7Epd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0872C4CEDD; Mon, 20 Jan 2025 13:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1737380952; bh=SVKVeCFZ4IiFQlohbcREUsgS7z9cGGnFhFBRjQAMfJ4=; h=From:To:Cc:Subject:Date:Reply-to:From; b=iq7t7Epd3nwY1mXkE6fxcAMHP9cLOkUK5Ro1cQLeuFami465vVF2R87+xnF//L2fG A7CzjAQIlJrdfDsBEW76u18tLwzCVEaG2BdOOTPu30GuAml3IQXXaZsdpf1OTIgFME fZkYRlyFgffZsvv04ux/qA8Sa1fm64+aVhOLGEqg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2025-21655: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period Date: Mon, 20 Jan 2025 14:49:01 +0100 Message-ID: <2025012000-CVE-2025-21655-2cc8@gregkh> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=2643; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=SVKVeCFZ4IiFQlohbcREUsgS7z9cGGnFhFBRjQAMfJ4=; b=owGbwMvMwCRo6H6F97bub03G02pJDOl9IT7Va5dYdCXca3x1MufL44s9PvMai+ukVC/cP/P/K 1PV83eHOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAi3PUMC47Wf1fcUF9VcjHT /E5L9Zz1BquKmhkWHP8pdeDfvF2rd1iuX3nMVtJRLHfOMwA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period. The Linux kernel CVE team has assigned CVE-2025-21655 to this issue. Affected and fixed versions =========================== Issue introduced in 6.1 with commit 21a091b970cdbcf3e8ff829234b51be6f9192766 and fixed in 6.1.125 with commit 6b63308c28987c6010b1180c72a6db4df6c68033 Issue introduced in 6.1 with commit 21a091b970cdbcf3e8ff829234b51be6f9192766 and fixed in 6.6.72 with commit 8efff2aa2d95dc437ab67c5b4a9f1d3f367baa10 Issue introduced in 6.1 with commit 21a091b970cdbcf3e8ff829234b51be6f9192766 and fixed in 6.12.10 with commit a7085c3ae43b86d4b3d1b8275e6a67f14257e3b7 Issue introduced in 6.1 with commit 21a091b970cdbcf3e8ff829234b51be6f9192766 and fixed in 6.13 with commit c9a40292a44e78f71258b8522655bffaf5753bdb Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2025-21655 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: io_uring/eventfd.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/6b63308c28987c6010b1180c72a6db4df6c68033 https://git.kernel.org/stable/c/8efff2aa2d95dc437ab67c5b4a9f1d3f367baa10 https://git.kernel.org/stable/c/a7085c3ae43b86d4b3d1b8275e6a67f14257e3b7 https://git.kernel.org/stable/c/c9a40292a44e78f71258b8522655bffaf5753bdb