| Message ID | 20220128082920.591115-1-francesco.dolcini@toradex.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] PCI: imx6: Handle the abort from user-space | expand |
Am Freitag, dem 28.01.2022 um 09:29 +0100 schrieb Francesco Dolcini: > From: Jason Liu <jason.hui.liu@nxp.com> > > The driver install one hook to handle the external abort, but issue > is that if the abort introduced from user space code, the following > code unsigned long instr = *(unsigned long *)pc; which will created > another data-abort(page domain fault) if CONFIG_CPU_SW_DOMAIN_PAN. > > The patch does not intent to use copy_from_user and then do the hack > due to the security consideration. In fact, we can just return and > report the external abort to user-space. > I'm not sure how userspace would be able to trigger this abort. Maybe invalid access to a device cfg space via sysfs? However the patch seems to do the right thing in that case. Acked-by: Lucas Stach <l.stach@pengutronix.de> > Signed-off-by: Jason Liu <jason.hui.liu@nxp.com> > Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com> > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > --- > We have this patch from NXP downstream kernel [1] in our kernel branch [2] > since a long time, to me it would make sense to upstream it. Any concern? > > [1] https://source.codeaurora.org/external/imxsupport/linux-imx/commit/?id=62dfb2fb953463dd1b6710567c9e174672a98f24 > [2] https://git.toradex.com/cgit/linux-toradex.git/commit/?id=2b42547cf659f979be2defdff6a99f921b33d0f1 > --- > drivers/pci/controller/dwc/pci-imx6.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c > index 6974bd5aa116..6b178a29e253 100644 > --- a/drivers/pci/controller/dwc/pci-imx6.c > +++ b/drivers/pci/controller/dwc/pci-imx6.c > @@ -27,6 +27,7 @@ > #include <linux/resource.h> > #include <linux/signal.h> > #include <linux/types.h> > +#include <linux/uaccess.h> > #include <linux/interrupt.h> > #include <linux/reset.h> > #include <linux/phy/phy.h> > @@ -297,8 +298,15 @@ static int imx6q_pcie_abort_handler(unsigned long addr, > unsigned int fsr, struct pt_regs *regs) > { > unsigned long pc = instruction_pointer(regs); > - unsigned long instr = *(unsigned long *)pc; > - int reg = (instr >> 12) & 15; > + unsigned long instr; > + int reg; > + > + /* if the abort from user-space, just return and report it */ > + if (user_mode(regs)) > + return 1; > + > + instr = *(unsigned long *)pc; > + reg = (instr >> 12) & 15; > > /* > * If the instruction being executed was a read,
Am Freitag, 28. Januar 2022, 10:25:11 CET schrieb Hongxing Zhu: > > -----Original Message----- > > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > Sent: 2022年1月28日 16:29 > > To: Hongxing Zhu <hongxing.zhu@nxp.com>; Lucas Stach > > <l.stach@pengutronix.de>; Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>; > > Rob Herring <robh@kernel.org>; Krzysztof Wilczyński <kw@linux.com>; > > Sascha Hauer <s.hauer@pengutronix.de>; Pengutronix Kernel Team > > <kernel@pengutronix.de>; Fabio Estevam <festevam@gmail.com>; > > dl-linux-imx <linux-imx@nxp.com>; Jason Liu <jason.hui.liu@nxp.com> > > Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org; > > linux-kernel@vger.kernel.org; Bjorn Helgaas <bhelgaas@google.com>; Shawn > > Guo <shawnguo@kernel.org>; Francesco Dolcini > > <francesco.dolcini@toradex.com> > > Subject: [RFC PATCH] PCI: imx6: Handle the abort from user-space > > > > From: Jason Liu <jason.hui.liu@nxp.com> > > > > The driver install one hook to handle the external abort, but issue is > > that if the abort introduced from user space code, the following code > > unsigned long instr = *(unsigned long *)pc; which will created another > > data-abort(page domain fault) if CONFIG_CPU_SW_DOMAIN_PAN. > > > > The patch does not intent to use copy_from_user and then do the hack due > > to the security consideration. In fact, we can just return and report > > the external abort to user-space. > > > > Signed-off-by: Jason Liu <jason.hui.liu@nxp.com> > > Reviewed-by: Richard Zhu <hongxing.zhu@nxp.com> > > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > > --- > > We have this patch from NXP downstream kernel [1] in our kernel branch > > [2] > > since a long time, to me it would make sense to upstream it. Any concern? > > > > [1] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsource. > > codeaurora.org%2Fexternal%2Fimxsupport%2Flinux-imx%2Fcommit%2F%3Fid > > %3D62dfb2fb953463dd1b6710567c9e174672a98f24&data=04%7C01%7 > > Chongxing.zhu%40nxp.com%7Ccbe193ab4c3e4ad11bcb08d9e2384a1f%7C68 > > 6ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637789553659549198%7 > > CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT > > iI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=Mwhx8DFF7EDJdpqTsHT > > %2BBAGzhQadDOqcgJnVjeoi1yk%3D&reserved=0 > > [2] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.tora > > > > dex.com%2Fcgit%2Flinux-toradex.git%2Fcommit%2F%3Fid%3D2b42547cf659f > > 979be2defdff6a99f921b33d0f1&data=04%7C01%7Chongxing.zhu%40nx > > p.com%7Ccbe193ab4c3e4ad11bcb08d9e2384a1f%7C686ea1d3bc2b4c6fa92c > > d99c5c301635%7C0%7C0%7C637789553659549198%7CUnknown%7CTWFp > > bGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI > > 6Mn0%3D%7C3000&sdata=QEW1frh8WacCzniWo4ng1cy3Z1UZ9uMRFw > > GBKuIh7zE%3D&reserved=0 > > --- > > > > drivers/pci/controller/dwc/pci-imx6.c | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > b/drivers/pci/controller/dwc/pci-imx6.c > > index 6974bd5aa116..6b178a29e253 100644 > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > @@ -27,6 +27,7 @@ > > > > #include <linux/resource.h> > > #include <linux/signal.h> > > #include <linux/types.h> > > > > +#include <linux/uaccess.h> > > > [Richard Zhu] Thanks for your kindly help. > This header include is not required actually, please remove it. It should be <linux/ptrace.h> instead, for using user_mode(). Best regards, Alexander > > #include <linux/interrupt.h> > > #include <linux/reset.h> > > #include <linux/phy/phy.h> > > > > @@ -297,8 +298,15 @@ static int imx6q_pcie_abort_handler(unsigned long > > addr, > > > > unsigned int fsr, struct pt_regs *regs) { > > > > unsigned long pc = instruction_pointer(regs); > > > > - unsigned long instr = *(unsigned long *)pc; > > - int reg = (instr >> 12) & 15; > > + unsigned long instr; > > + int reg; > > + > > + /* if the abort from user-space, just return and report it */ > > + if (user_mode(regs)) > > + return 1; > > + > > + instr = *(unsigned long *)pc; > > + reg = (instr >> 12) & 15; > > > > > > /* > > > > * If the instruction being executed was a read, > > > > -- > > 2.25.1 > >
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 6974bd5aa116..6b178a29e253 100644 --- a/drivers/pci/controller/dwc/pci-imx6.c +++ b/drivers/pci/controller/dwc/pci-imx6.c @@ -27,6 +27,7 @@ #include <linux/resource.h> #include <linux/signal.h> #include <linux/types.h> +#include <linux/uaccess.h> #include <linux/interrupt.h> #include <linux/reset.h> #include <linux/phy/phy.h> @@ -297,8 +298,15 @@ static int imx6q_pcie_abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { unsigned long pc = instruction_pointer(regs); - unsigned long instr = *(unsigned long *)pc; - int reg = (instr >> 12) & 15; + unsigned long instr; + int reg; + + /* if the abort from user-space, just return and report it */ + if (user_mode(regs)) + return 1; + + instr = *(unsigned long *)pc; + reg = (instr >> 12) & 15; /* * If the instruction being executed was a read,