From patchwork Tue Jul 30 05:15:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 13746590 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 BC4BA2114; Tue, 30 Jul 2024 05:14:47 +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=1722316487; cv=none; b=KhRfTDU6DUnDtaQQfW5MGZHFWPgHgRBobAm7+AKL9XTeQevWGIp9VZO91dBr80fi+rKbSl00SGDKHRwB7lhlIE0j5+Ttvl2FWaGEgryqA/XqSKiaf/TWO5gtAyLP60hjCPJaxrwA/smPtbMZT+i+PIyC+1mlG6yBCHDeKAIqvj8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722316487; c=relaxed/simple; bh=9+GUEXuBx9YsLhq/QX8kwA5yzV3pP+uMxTKcxPU/ZEo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=qUK5H1xOYatCAKHFePaLmqlHawJ19DljFHIHeIzedtERIK/pReYq0ekdkwLRYpJeUyP73ci0DjNFrfpCNF0sSyJ/6AAeNbADjJx/CrAxOKG2vRmrj1kcZzBvzNJO6QRCIHcU/I/I20tOB/g53qZor3JleoSb+zxw+7uDkpEIqR4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rWIbF0Kx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rWIbF0Kx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 797EAC32782; Tue, 30 Jul 2024 05:14:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722316487; bh=9+GUEXuBx9YsLhq/QX8kwA5yzV3pP+uMxTKcxPU/ZEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rWIbF0KxXlh8S1V1TVLXnVofeyJl19QhXkLhUf3Nprmx89CCp69kbYXq8yjhLmqlF //2hXU2TlRPNnsmDMEsWDFTNV6eYrytNiPWRVAmV7lBXcsagpXSZU6wu4qvsGdH57X zkMIhH3mPFI7F2ZRqnD7oZnkjUp9Ig9Wi8N4y3pLf/QS8CATTYMy5FTeXaidnaeyfl i8Q5bXEiLJYOtWSW71HyNpGkhYqKAvTzFdGvKNs3Xc4KNzGV19SLk7dsNmySbjhP5w I0BWNsAmQyVmzOTWzibAxgKO6WYR964QQxvLNEJVHcs9CIUBft0ic9Q1blR+B6X7KK I9QwqL2uE0iRw== From: viro@kernel.org To: linux-fsdevel@vger.kernel.org Cc: amir73il@gmail.com, bpf@vger.kernel.org, brauner@kernel.org, cgroups@vger.kernel.org, kvm@vger.kernel.org, netdev@vger.kernel.org, torvalds@linux-foundation.org Subject: [PATCH 01/39] memcg_write_event_control(): fix a user-triggerable oops Date: Tue, 30 Jul 2024 01:15:47 -0400 Message-Id: <20240730051625.14349-1-viro@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240730050927.GC5334@ZenIV> References: <20240730050927.GC5334@ZenIV> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Al Viro we are *not* guaranteed that anything past the terminating NUL is mapped (let alone initialized with anything sane). [the sucker got moved in mainline] Signed-off-by: Al Viro Acked-by: Michal Hocko --- mm/memcontrol-v1.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 2aeea4d8bf8e..417c96f2da28 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1842,9 +1842,12 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, buf = endp + 1; cfd = simple_strtoul(buf, &endp, 10); - if ((*endp != ' ') && (*endp != '\0')) + if (*endp == '\0') + buf = endp; + else if (*endp == ' ') + buf = endp + 1; + else return -EINVAL; - buf = endp + 1; event = kzalloc(sizeof(*event), GFP_KERNEL); if (!event)