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 5D9AB6BB5B; Mon, 22 Sep 2025 04:11:16 +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=1758514277; cv=none; b=nDwolKWcl6/Ra4F26KCGzsJklQEHj96eOkqr5a0+2NvgEK9wmZyEX0AWvOvCLG4Eydr52aON8O7nGQpVFnN3CzyLl7wWAnDXwMeiOM2mAvExeH0M0gJXvOufr5iBg2SA22hWzgQsp64E0Du2rnIuVILpj6QMbw5euCWSOvoQ5TE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758514277; c=relaxed/simple; bh=qLe5+D3p/KCHuEXmJDeqOmQHa8PWtS/4MQOlxPYDX7E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iUsbag6F18MUgMQsaVindSnbweC9ylZF+r+LpsGrHLDe+ytOBJ2eZ2YQIgg7ORDEpOC5bUamSnuwBzhHpcTtQiuPQREtRPXMu2oTqgyF/NYGVfg2qxBLQshecnqn4mq0awDVz08HjAn0xQpxcRfPa1Ilm0oTcLyAhztYgvG7kb4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LA1B5JnG; 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="LA1B5JnG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EED2C4CEF5; Mon, 22 Sep 2025 04:11:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758514276; bh=qLe5+D3p/KCHuEXmJDeqOmQHa8PWtS/4MQOlxPYDX7E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LA1B5JnGwrN9VzNVeM/dbIS00PgdcxFS4733F2v2T9YlH3M5yujhhvRNDpVcR4vtz yKbWstSh5+BAbFl2n4jD2hTE8bmJaYVdU7LRWUOnrgfFEmaIpsE1e6RI4gfTjGaEsc 85VFdX7B2MIYH4SYEs0Ivqwo+TO7+n+dR3Vl5kHTlMLcTGnaJ2EbbWAj5rw2NLFKpu 6r9EQIChNAGv1G7HYfGXHB53zhT6apKxF1sdDqWm0sWwBTQ3uqGB2up4ntxnaBcWDi kA2g7nHKA4D5oBZSNt1ROCBEnJc5QVbhuoT5Xre+fv8cuA34uaqpAS6L1SwCv3vMae WT9ve0Qz92AYg== Date: Mon, 22 Sep 2025 09:41:10 +0530 From: Sumit Garg To: Jens Wiklander Cc: linux-kernel@vger.kernel.org, op-tee@lists.trustedfirmware.org, Jerome Forissier , stable@vger.kernel.org, Masami Ichikawa Subject: Re: [PATCH] tee: fix register_shm_helper() Message-ID: References: <20250919124217.2934718-1-jens.wiklander@linaro.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250919124217.2934718-1-jens.wiklander@linaro.org> On Fri, Sep 19, 2025 at 02:40:16PM +0200, Jens Wiklander wrote: > In register_shm_helper(), fix incorrect error handling for a call to > iov_iter_extract_pages(). A case is missing for when > iov_iter_extract_pages() only got some pages and return a number larger > than 0, but not the requested amount. > > This fixes a possible NULL pointer dereference following a bad input from > ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped. > > Cc: stable@vger.kernel.org > Reported-by: Masami Ichikawa > Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=u9W+-g@mail.gmail.com/ > Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration") > Signed-off-by: Jens Wiklander > --- > drivers/tee/tee_shm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index daf6e5cfd59a..6ed7d030f4ed 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, > > len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0, > &off); > - if (unlikely(len <= 0)) { > + if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { > + if (len > 0) { > + /* > + * If we only got a few pages, update to release > + * the correct amount below. > + */ > + shm->num_pages = len / PAGE_SIZE; > + ret = ERR_PTR(-ENOMEM); > + goto err_put_shm_pages; > + } > ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); > goto err_free_shm_pages; > } Rather than operating directly on "len" without checking for error code first doesn't seems appropriate to me. How about following diff instead? diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index daf6e5cfd59a..cb52bc51943e 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -319,6 +319,14 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, if (unlikely(len <= 0)) { ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); goto err_free_shm_pages; + } else if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { + /* + * If we only got a few pages, update to release the correct + * amount below. + */ + shm->num_pages = len / PAGE_SIZE; + ret = ERR_PTR(-ENOMEM); + goto err_put_shm_pages; } /* -Sumit > -- > 2.43.0 >