summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/ptrace/ptrace-view.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/ptrace/ptrace-view.c')
-rw-r--r--arch/powerpc/kernel/ptrace/ptrace-view.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c
index 13208a9a02ca..19823a250aa0 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -470,13 +470,15 @@ static int pkey_active(struct task_struct *target, const struct user_regset *reg
static int pkey_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
+ int ret;
+
BUILD_BUG_ON(TSO(amr) + sizeof(unsigned long) != TSO(iamr));
- BUILD_BUG_ON(TSO(iamr) + sizeof(unsigned long) != TSO(uamor));
if (!arch_pkeys_enabled())
return -ENODEV;
- return membuf_write(&to, &target->thread.amr, ELF_NPKEY * sizeof(unsigned long));
+ membuf_write(&to, &target->thread.amr, 2 * sizeof(unsigned long));
+ return membuf_store(&to, default_uamor);
}
static int pkey_set(struct task_struct *target, const struct user_regset *regset,
@@ -498,9 +500,17 @@ static int pkey_set(struct task_struct *target, const struct user_regset *regset
if (ret)
return ret;
- /* UAMOR determines which bits of the AMR can be set from userspace. */
- target->thread.amr = (new_amr & target->thread.uamor) |
- (target->thread.amr & ~target->thread.uamor);
+ /*
+ * UAMOR determines which bits of the AMR can be set from userspace.
+ * UAMOR value 0b11 indicates that the AMR value can be modified
+ * from userspace. If the kernel is using a specific key, we avoid
+ * userspace modifying the AMR value for that key by masking them
+ * via UAMOR 0b00.
+ *
+ * Pick the AMR values for the keys that kernel is using. This
+ * will be indicated by the ~default_uamor bits.
+ */
+ target->thread.amr = (new_amr & default_uamor) | (target->thread.amr & ~default_uamor);
return 0;
}