The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 8e05f1b4f27d07a0f93e7c6fd28525a5d082b85c
Gitweb: https://git.kernel.org/tip/8e05f1b4f27d07a0f93e7c6fd28525a5d082b85c
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Mon, 15 Jul 2019 10:08:48 -07:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 26 Nov 2019 22:00:12 +01:00
x86/ptrace: Remove set_segment_reg() implementations for current
seg_segment_reg() should be unreachable with task == current.
Rather than confusingly trying to make it work, just explicitly
disable this case.
(regset->get is used for current in the coredump code, but the ->set
interface is only used for ptrace, and you can't ptrace yourself.)
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/ptrace.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 066e5b0..3b3b169 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -182,6 +182,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
+ if (WARN_ON_ONCE(task == current))
+ return -EIO;
+
/*
* The value argument was already truncated to 16 bits.
*/
@@ -209,10 +212,7 @@ static int set_segment_reg(struct task_struct *task,
break;
case offsetof(struct user_regs_struct, gs):
- if (task == current)
- set_user_gs(task_pt_regs(task), value);
- else
- task_user_gs(task) = value;
+ task_user_gs(task) = value;
}
return 0;
@@ -272,6 +272,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
+ if (WARN_ON_ONCE(task == current))
+ return -EIO;
+
/*
* The value argument was already truncated to 16 bits.
*/
@@ -281,23 +284,15 @@ static int set_segment_reg(struct task_struct *task,
switch (offset) {
case offsetof(struct user_regs_struct,fs):
task->thread.fsindex = value;
- if (task == current)
- loadsegment(fs, task->thread.fsindex);
break;
case offsetof(struct user_regs_struct,gs):
task->thread.gsindex = value;
- if (task == current)
- load_gs_index(task->thread.gsindex);
break;
case offsetof(struct user_regs_struct,ds):
task->thread.ds = value;
- if (task == current)
- loadsegment(ds, task->thread.ds);
break;
case offsetof(struct user_regs_struct,es):
task->thread.es = value;
- if (task == current)
- loadsegment(es, task->thread.es);
break;
/*
|