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authorHelge Deller <deller@gmx.de>2019-07-16 21:43:11 +0200
committerHelge Deller <deller@gmx.de>2019-07-17 23:11:27 +0200
commit10835c854685393a921b68f529bf740fa7c9984d (patch)
tree06bff8910b1370c736c4e189f775f6e2b8191e60 /arch
parentc309b6f24222246c18a8b65d3950e6e755440865 (diff)
parisc: Fix kernel panic due invalid values in IAOQ0 or IAOQ1
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/kernel/ptrace.c28
1 files changed, 18 insertions, 10 deletions
diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index f642ba378ffa..040ff16dd5e7 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -167,6 +167,9 @@ 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) ||
@@ -228,16 +231,18 @@ 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,
@@ -281,9 +286,12 @@ 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) ||