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Subject[PATCH 3.19.y-ckt 36/56] parisc: Fix kernel crash with reversed copy_from_user()
Date
3.19.8-ckt19 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Helge Deller <deller@gmx.de>

commit ef72f3110d8b19f4c098a0bff7ed7d11945e70c6 upstream.

The kernel module testcase (lib/test_user_copy.c) exhibited a kernel
crash on parisc if the parameters for copy_from_user were reversed
("illegal reversed copy_to_user" testcase).

Fix this potential crash by checking the fault handler if the faulting
address is in the exception table.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
arch/parisc/kernel/traps.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 7f67c4c..bbf2265 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -798,6 +798,9 @@ void notrace handle_interruption(int code, struct pt_regs *regs)

if (fault_space == 0 && !in_atomic())
{
+ /* Clean up and return if in exception table. */
+ if (fixup_exception(regs))
+ return;
pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
parisc_terminate("Kernel Fault", regs, code, fault_address);
}
--
2.7.4
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