Patchwork [v2,1/2] pci: imx6: avoid dereferencing program counter from user mode

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Submitter Stefan Agner
Date Dec. 4, 2018, 1:27 p.m.
Message ID <20181204132733.14422-1-stefan@agner.ch>
Download mbox | patch
Permalink /patch/671883/
State New
Headers show

Comments

Stefan Agner - Dec. 4, 2018, 1:27 p.m.
The custom fault handler is currently only meant to handle kernel
mode bus faults. Exit in case the abort happened in user mode.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 69f86234f7c0..54a29e441303 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -270,8 +270,14 @@  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 (user_mode(regs))
+		return 1;
+
+	instr = *(unsigned long *)pc;
+	reg = (instr >> 12) & 15;
 
 	/*
 	 * If the instruction being executed was a read,