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Message-ID: <20240829102320-mutt-send-email-mst@kernel.org>
Date: Thu, 29 Aug 2024 10:23:35 -0400
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Philipp Stanner <pstanner@...hat.com>
Cc: Jens Axboe <axboe@...nel.dk>, Wu Hao <hao.wu@...el.com>,
Tom Rix <trix@...hat.com>, Moritz Fischer <mdf@...nel.org>,
Xu Yilun <yilun.xu@...el.com>, Andy Shevchenko <andy@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Alvaro Karsz <alvaro.karsz@...id-run.com>,
Jason Wang <jasowang@...hat.com>,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Eugenio PĂ©rez <eperezma@...hat.com>,
Richard Cochran <richardcochran@...il.com>,
Damien Le Moal <dlemoal@...nel.org>, Hannes Reinecke <hare@...e.de>,
John Garry <john.g.garry@...cle.com>, linux-block@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-fpga@...r.kernel.org,
linux-gpio@...r.kernel.org, netdev@...r.kernel.org,
linux-pci@...r.kernel.org, virtualization@...ts.linux.dev,
stable@...r.kernel.org,
Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: Re: [PATCH v5 6/7] vdpa: solidrun: Fix UB bug with devres
On Thu, Aug 29, 2024 at 04:16:25PM +0200, Philipp Stanner wrote:
> In psnet_open_pf_bar() and snet_open_vf_bar() a string later passed to
> pcim_iomap_regions() is placed on the stack. Neither
> pcim_iomap_regions() nor the functions it calls copy that string.
>
> Should the string later ever be used, this, consequently, causes
> undefined behavior since the stack frame will by then have disappeared.
>
> Fix the bug by allocating the strings on the heap through
> devm_kasprintf().
>
> Cc: stable@...r.kernel.org # v6.3
> Fixes: 51a8f9d7f587 ("virtio: vdpa: new SolidNET DPU driver.")
> Reported-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> Closes: https://lore.kernel.org/all/74e9109a-ac59-49e2-9b1d-d825c9c9f891@wanadoo.fr/
> Suggested-by: Andy Shevchenko <andy@...nel.org>
> Signed-off-by: Philipp Stanner <pstanner@...hat.com>
Post this separately, so I can apply?
> ---
> drivers/vdpa/solidrun/snet_main.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/solidrun/snet_main.c b/drivers/vdpa/solidrun/snet_main.c
> index 99428a04068d..c8b74980dbd1 100644
> --- a/drivers/vdpa/solidrun/snet_main.c
> +++ b/drivers/vdpa/solidrun/snet_main.c
> @@ -555,7 +555,7 @@ static const struct vdpa_config_ops snet_config_ops = {
>
> static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
> {
> - char name[50];
> + char *name;
> int ret, i, mask = 0;
> /* We don't know which BAR will be used to communicate..
> * We will map every bar with len > 0.
> @@ -573,7 +573,10 @@ static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
> return -ENODEV;
> }
>
> - snprintf(name, sizeof(name), "psnet[%s]-bars", pci_name(pdev));
> + name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "psnet[%s]-bars", pci_name(pdev));
> + if (!name)
> + return -ENOMEM;
> +
> ret = pcim_iomap_regions(pdev, mask, name);
> if (ret) {
> SNET_ERR(pdev, "Failed to request and map PCI BARs\n");
> @@ -590,10 +593,13 @@ static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
>
> static int snet_open_vf_bar(struct pci_dev *pdev, struct snet *snet)
> {
> - char name[50];
> + char *name;
> int ret;
>
> - snprintf(name, sizeof(name), "snet[%s]-bar", pci_name(pdev));
> + name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "snet[%s]-bars", pci_name(pdev));
> + if (!name)
> + return -ENOMEM;
> +
> /* Request and map BAR */
> ret = pcim_iomap_regions(pdev, BIT(snet->psnet->cfg.vf_bar), name);
> if (ret) {
> --
> 2.46.0
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