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authorHelge Deller <deller@gmx.de>2019-07-04 03:44:17 +0200
committerHelge Deller <deller@gmx.de>2019-07-17 23:11:27 +0200
commit34c32fc603311a72cb558e5e337555434f64c27b (patch)
tree2fc6df60be3a37856dec2332b73a583eca40b831 /arch
parent10835c854685393a921b68f529bf740fa7c9984d (diff)
parisc: Ensure userspace privilege for ptraced processes in regset functions
On parisc the privilege level of a process is stored in the lowest two bits of the instruction pointers (IAOQ0 and IAOQ1). On Linux we use privilege level 0 for the kernel and privilege level 3 for user-space. So userspace should not be allowed to modify IAOQ0 or IAOQ1 of a ptraced process to change it's privilege level to e.g. 0 to try to gain kernel privileges. This patch prevents such modifications in the regset support functions by always setting the two lowest bits to one (which relates to privilege level 3 for user-space) if IAOQ0 or IAOQ1 are modified via ptrace regset calls. Link: https://bugs.gentoo.org/481768 Cc: <stable@vger.kernel.org> # v4.7+ Tested-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/kernel/ptrace.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 040ff16dd5e7..9f6ff7bc06f9 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -504,7 +504,8 @@ static void set_reg(struct pt_regs *regs, int num, unsigned long val)
return;
case RI(iaoq[0]):
case RI(iaoq[1]):
- regs->iaoq[num - RI(iaoq[0])] = val;
+ /* set 2 lowest bits to ensure userspace privilege: */
+ regs->iaoq[num - RI(iaoq[0])] = val | 3;
return;
case RI(sar): regs->sar = val;
return;