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* [tip: x86/iopl] x86/ptrace: Prevent truncation of bitmap size
@ 2019-11-16 11:51 tip-bot2 for Thomas Gleixner
  0 siblings, 0 replies; 2+ messages in thread
From: tip-bot2 for Thomas Gleixner @ 2019-11-16 11:51 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Thomas Gleixner, Ingo Molnar, Andy Lutomirski, Borislav Petkov,
	linux-kernel

The following commit has been merged into the x86/iopl branch of tip:

Commit-ID:     8c40397f22a4ff7996d3abdc2d9d1d90f9fc8054
Gitweb:        https://git.kernel.org/tip/8c40397f22a4ff7996d3abdc2d9d1d90f9fc8054
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Mon, 11 Nov 2019 23:03:15 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 16 Nov 2019 11:23:59 +01:00

x86/ptrace: Prevent truncation of bitmap size

The active() callback of the IO bitmap regset divides the IO bitmap size by
the word size (32/64 bit). As the I/O bitmap size is in bytes the active
check fails for bitmap sizes of 1-3 bytes on 32bit and 1-7 bytes on 64bit.

Use DIV_ROUND_UP() instead.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>


---
 arch/x86/kernel/ptrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 3c5bbe8..7c52674 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -697,7 +697,7 @@ static int ptrace_set_debugreg(struct task_struct *tsk, int n,
 static int ioperm_active(struct task_struct *target,
 			 const struct user_regset *regset)
 {
-	return target->thread.io_bitmap_max / regset->size;
+	return DIV_ROUND_UP(target->thread.io_bitmap_max, regset->size);
 }
 
 static int ioperm_get(struct task_struct *target,

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [tip: x86/iopl] x86/ptrace: Prevent truncation of bitmap size
  2019-11-13 20:42 [patch V3 01/20] " Thomas Gleixner
@ 2019-11-15 21:12 ` tip-bot2 for Thomas Gleixner
  0 siblings, 0 replies; 2+ messages in thread
From: tip-bot2 for Thomas Gleixner @ 2019-11-15 21:12 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Thomas Gleixner, Ingo Molnar, Andy Lutomirski,
	Peter Zijlstra (Intel),
	Borislav Petkov, linux-kernel

The following commit has been merged into the x86/iopl branch of tip:

Commit-ID:     c5d623b17c2424272b3355a524b094ff02cfd9aa
Gitweb:        https://git.kernel.org/tip/c5d623b17c2424272b3355a524b094ff02cfd9aa
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Wed, 13 Nov 2019 21:42:41 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 14 Nov 2019 20:14:59 +01:00

x86/ptrace: Prevent truncation of bitmap size

The active() callback of the IO bitmap regset divides the IO bitmap size by
the word size (32/64 bit). As the I/O bitmap size is in bytes the active
check fails for bitmap sizes of 1-3 bytes on 32bit and 1-7 bytes on 64bit.

Use DIV_ROUND_UP() instead.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191113210103.819769574@linutronix.de



---
 arch/x86/kernel/ptrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 3c5bbe8..7c52674 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -697,7 +697,7 @@ static int ptrace_set_debugreg(struct task_struct *tsk, int n,
 static int ioperm_active(struct task_struct *target,
 			 const struct user_regset *regset)
 {
-	return target->thread.io_bitmap_max / regset->size;
+	return DIV_ROUND_UP(target->thread.io_bitmap_max, regset->size);
 }
 
 static int ioperm_get(struct task_struct *target,

^ permalink raw reply related	[flat|nested] 2+ messages in thread

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2019-11-16 11:51 [tip: x86/iopl] x86/ptrace: Prevent truncation of bitmap size tip-bot2 for Thomas Gleixner
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2019-11-13 20:42 [patch V3 01/20] " Thomas Gleixner
2019-11-15 21:12 ` [tip: x86/iopl] " tip-bot2 for Thomas Gleixner

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