* [PATCH] um: Fix PTRACE_POKEUSER on x86_64
@ 2017-03-31 22:41 Richard Weinberger
2017-04-01 12:58 ` Geert Uytterhoeven
2017-05-03 20:54 ` Richard Weinberger
0 siblings, 2 replies; 5+ messages in thread
From: Richard Weinberger @ 2017-03-31 22:41 UTC (permalink / raw)
To: linux-kernel; +Cc: user-mode-linux-devel, jdike, richard, stable
This is broken since ever but sadly nobody noticed.
Recent versions of GDB set DR_CONTROL unconditionally and
UML dies due to a heap corruption. It turns out that
the PTRACE_POKEUSER was copy&pasted from i386 and assumes
that addresses are 4 bytes long.
Fix that by using 8 as address size in the calculation.
Cc: <stable@vger.kernel.org>
Reported-by: jie cao <cj3054@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
arch/x86/um/ptrace_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
index a5c9910d234f..09a085bde0d4 100644
--- a/arch/x86/um/ptrace_64.c
+++ b/arch/x86/um/ptrace_64.c
@@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data)
else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
(addr <= offsetof(struct user, u_debugreg[7]))) {
addr -= offsetof(struct user, u_debugreg[0]);
- addr = addr >> 2;
+ addr = addr >> 3;
if ((addr == 4) || (addr == 5))
return -EIO;
child->thread.arch.debugregs[addr] = data;
--
2.10.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] um: Fix PTRACE_POKEUSER on x86_64
2017-03-31 22:41 [PATCH] um: Fix PTRACE_POKEUSER on x86_64 Richard Weinberger
@ 2017-04-01 12:58 ` Geert Uytterhoeven
2017-05-03 20:54 ` Richard Weinberger
1 sibling, 0 replies; 5+ messages in thread
From: Geert Uytterhoeven @ 2017-04-01 12:58 UTC (permalink / raw)
To: Richard Weinberger; +Cc: linux-kernel, uml-devel, Jeff Dike, stable
Hi Richard,
On Sat, Apr 1, 2017 at 12:41 AM, Richard Weinberger <richard@nod.at> wrote:
> This is broken since ever but sadly nobody noticed.
> Recent versions of GDB set DR_CONTROL unconditionally and
> UML dies due to a heap corruption. It turns out that
> the PTRACE_POKEUSER was copy&pasted from i386 and assumes
> that addresses are 4 bytes long.
>
> Fix that by using 8 as address size in the calculation.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: jie cao <cj3054@gmail.com>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> arch/x86/um/ptrace_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
> index a5c9910d234f..09a085bde0d4 100644
> --- a/arch/x86/um/ptrace_64.c
> +++ b/arch/x86/um/ptrace_64.c
> @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data)
> else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
> (addr <= offsetof(struct user, u_debugreg[7]))) {
> addr -= offsetof(struct user, u_debugreg[0]);
> - addr = addr >> 2;
> + addr = addr >> 3;
While at it:
addr >>= 3;
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [uml-devel] [PATCH] um: Fix PTRACE_POKEUSER on x86_64
2017-03-31 22:41 [PATCH] um: Fix PTRACE_POKEUSER on x86_64 Richard Weinberger
2017-04-01 12:58 ` Geert Uytterhoeven
@ 2017-05-03 20:54 ` Richard Weinberger
1 sibling, 0 replies; 5+ messages in thread
From: Richard Weinberger @ 2017-05-03 20:54 UTC (permalink / raw)
To: Richard Weinberger; +Cc: LKML, Jeff Dike, stable, user-mode-linux-devel
On Sat, Apr 1, 2017 at 12:41 AM, Richard Weinberger <richard@nod.at> wrote:
> This is broken since ever but sadly nobody noticed.
> Recent versions of GDB set DR_CONTROL unconditionally and
> UML dies due to a heap corruption. It turns out that
> the PTRACE_POKEUSER was copy&pasted from i386 and assumes
> that addresses are 4 bytes long.
>
> Fix that by using 8 as address size in the calculation.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: jie cao <cj3054@gmail.com>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> arch/x86/um/ptrace_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
> index a5c9910d234f..09a085bde0d4 100644
> --- a/arch/x86/um/ptrace_64.c
> +++ b/arch/x86/um/ptrace_64.c
> @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data)
> else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
> (addr <= offsetof(struct user, u_debugreg[7]))) {
> addr -= offsetof(struct user, u_debugreg[0]);
> - addr = addr >> 2;
> + addr = addr >> 3;
> if ((addr == 4) || (addr == 5))
> return -EIO;
> child->thread.arch.debugregs[addr] = data;
Applied.
--
Thanks,
//richard
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [uml-devel] [PATCH] um: Fix PTRACE_POKEUSER on x86_64
@ 2017-05-03 20:54 ` Richard Weinberger
0 siblings, 0 replies; 5+ messages in thread
From: Richard Weinberger @ 2017-05-03 20:54 UTC (permalink / raw)
To: Richard Weinberger; +Cc: LKML, Jeff Dike, stable, user-mode-linux-devel
On Sat, Apr 1, 2017 at 12:41 AM, Richard Weinberger <richard@nod.at> wrote:
> This is broken since ever but sadly nobody noticed.
> Recent versions of GDB set DR_CONTROL unconditionally and
> UML dies due to a heap corruption. It turns out that
> the PTRACE_POKEUSER was copy&pasted from i386 and assumes
> that addresses are 4 bytes long.
>
> Fix that by using 8 as address size in the calculation.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: jie cao <cj3054@gmail.com>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> arch/x86/um/ptrace_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
> index a5c9910d234f..09a085bde0d4 100644
> --- a/arch/x86/um/ptrace_64.c
> +++ b/arch/x86/um/ptrace_64.c
> @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data)
> else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
> (addr <= offsetof(struct user, u_debugreg[7]))) {
> addr -= offsetof(struct user, u_debugreg[0]);
> - addr = addr >> 2;
> + addr = addr >> 3;
> if ((addr == 4) || (addr == 5))
> return -EIO;
> child->thread.arch.debugregs[addr] = data;
Applied.
--
Thanks,
//richard
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [uml-devel] [PATCH] um: Fix PTRACE_POKEUSER on x86_64
@ 2017-05-03 20:54 ` Richard Weinberger
0 siblings, 0 replies; 5+ messages in thread
From: Richard Weinberger @ 2017-05-03 20:54 UTC (permalink / raw)
To: Richard Weinberger; +Cc: user-mode-linux-devel, Jeff Dike, LKML, stable
On Sat, Apr 1, 2017 at 12:41 AM, Richard Weinberger <richard@nod.at> wrote:
> This is broken since ever but sadly nobody noticed.
> Recent versions of GDB set DR_CONTROL unconditionally and
> UML dies due to a heap corruption. It turns out that
> the PTRACE_POKEUSER was copy&pasted from i386 and assumes
> that addresses are 4 bytes long.
>
> Fix that by using 8 as address size in the calculation.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: jie cao <cj3054@gmail.com>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> arch/x86/um/ptrace_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
> index a5c9910d234f..09a085bde0d4 100644
> --- a/arch/x86/um/ptrace_64.c
> +++ b/arch/x86/um/ptrace_64.c
> @@ -125,7 +125,7 @@ int poke_user(struct task_struct *child, long addr, long data)
> else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
> (addr <= offsetof(struct user, u_debugreg[7]))) {
> addr -= offsetof(struct user, u_debugreg[0]);
> - addr = addr >> 2;
> + addr = addr >> 3;
> if ((addr == 4) || (addr == 5))
> return -EIO;
> child->thread.arch.debugregs[addr] = data;
Applied.
--
Thanks,
//richard
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2017-03-31 22:41 [PATCH] um: Fix PTRACE_POKEUSER on x86_64 Richard Weinberger
2017-04-01 12:58 ` Geert Uytterhoeven
2017-05-03 20:54 ` [uml-devel] " Richard Weinberger
2017-05-03 20:54 ` Richard Weinberger
2017-05-03 20:54 ` Richard Weinberger
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