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| author | Helge Deller <deller@gmx.de> | 2019-07-04 04:44:17 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-26 10:11:07 +0300 |
| commit | 325d2d7eedbf0401d798780e39098001e6ddceb3 (patch) | |
| tree | 1cbb63a266ed37789c18ca15d2d0a0e42488074a | |
| parent | c40ecbe1f6ef867769590cec31a11dda60c17141 (diff) | |
| download | linux-325d2d7eedbf0401d798780e39098001e6ddceb3.tar.xz | |
parisc: Ensure userspace privilege for ptraced processes in regset functions
commit 34c32fc603311a72cb558e5e337555434f64c27b upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/parisc/kernel/ptrace.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c index a3d2fb4e6dd2..98d7f8c08df4 100644 --- a/arch/parisc/kernel/ptrace.c +++ b/arch/parisc/kernel/ptrace.c @@ -496,7 +496,8 @@ 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; |