diff options
| author | Helge Deller <deller@gmx.de> | 2019-07-16 21:43:11 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 07:28:42 +0200 |
| commit | a6766bb9da3572c19b42aa9a43f0bd9b03792c03 (patch) | |
| tree | 8b2e6977839062660e7d1cfb7859560f78f6b7c6 /arch/parisc | |
| parent | 6eb5c6a472d0f7625f1cceb556032f6ba3a23798 (diff) | |
parisc: Fix kernel panic due invalid values in IAOQ0 or IAOQ1
commit 10835c854685393a921b68f529bf740fa7c9984d 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 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 calls in the native and compat ptrace paths.
Link: https://bugs.gentoo.org/481768
Reported-by: Jeroen Roovers <jer@gentoo.org>
Cc: <stable@vger.kernel.org>
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>
Diffstat (limited to 'arch/parisc')
| -rw-r--r-- | arch/parisc/kernel/ptrace.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c index f2b85d6c33cf..f468a5b44508 100644 --- a/arch/parisc/kernel/ptrace.c +++ b/arch/parisc/kernel/ptrace.c @@ -171,6 +171,9 @@ long arch_ptrace(struct task_struct *child, long request, if ((addr & (sizeof(unsigned long)-1)) || addr >= sizeof(struct pt_regs)) break; + if (addr == PT_IAOQ0 || addr == PT_IAOQ1) { + data |= 3; /* ensure userspace privilege */ + } if ((addr >= PT_GR1 && addr <= PT_GR31) || addr == PT_IAOQ0 || addr == PT_IAOQ1 || (addr >= PT_FR0 && addr <= PT_FR31 + 4) || @@ -232,16 +235,18 @@ long arch_ptrace(struct task_struct *child, long request, static compat_ulong_t translate_usr_offset(compat_ulong_t offset) { - if (offset < 0) - return sizeof(struct pt_regs); - else if (offset <= 32*4) /* gr[0..31] */ - return offset * 2 + 4; - else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */ - return offset + 32*4; - else if (offset < sizeof(struct pt_regs)/2 + 32*4) - return offset * 2 + 4 - 32*8; + compat_ulong_t pos; + + if (offset < 32*4) /* gr[0..31] */ + pos = offset * 2 + 4; + else if (offset < 32*4+32*8) /* fr[0] ... fr[31] */ + pos = (offset - 32*4) + PT_FR0; + else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */ + pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4; else - return sizeof(struct pt_regs); + pos = sizeof(struct pt_regs); + + return pos; } long compat_arch_ptrace(struct task_struct *child, compat_long_t request, @@ -285,9 +290,12 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, addr = translate_usr_offset(addr); if (addr >= sizeof(struct pt_regs)) break; + if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) { + data |= 3; /* ensure userspace privilege */ + } if (addr >= PT_FR0 && addr <= PT_FR31 + 4) { /* Special case, fp regs are 64 bits anyway */ - *(__u64 *) ((char *) task_regs(child) + addr) = data; + *(__u32 *) ((char *) task_regs(child) + addr) = data; ret = 0; } else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) || |