* [PATCH][RFC] [powerpc] arch_ptrace() uses of access_ok() are pointless
@ 2018-05-27 22:34 Al Viro
2018-05-28 19:25 ` Mathieu Malaterre
0 siblings, 1 reply; 3+ messages in thread
From: Al Viro @ 2018-05-27 22:34 UTC (permalink / raw)
To: linuxppc-dev; +Cc: linux-kernel, Michael Ellerman
make it use copy_{from,to}_user(), rather than access_ok() +
__copy_...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/powerpc/kernel/ptrace.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index d23cf632edf0..d8b0fd2fa3aa 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -3081,27 +3081,19 @@ long arch_ptrace(struct task_struct *child, long request,
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
- if (!access_ok(VERIFY_WRITE, datavp,
- sizeof(struct ppc_debug_info)))
+ if (unlikely(copy_to_user(datavp, &dbginfo,
+ sizeof(struct ppc_debug_info)))
return -EFAULT;
- ret = __copy_to_user(datavp, &dbginfo,
- sizeof(struct ppc_debug_info)) ?
- -EFAULT : 0;
- break;
+ return 0;
}
case PPC_PTRACE_SETHWDEBUG: {
struct ppc_hw_breakpoint bp_info;
- if (!access_ok(VERIFY_READ, datavp,
- sizeof(struct ppc_hw_breakpoint)))
- return -EFAULT;
- ret = __copy_from_user(&bp_info, datavp,
- sizeof(struct ppc_hw_breakpoint)) ?
- -EFAULT : 0;
- if (!ret)
- ret = ppc_set_hwdebug(child, &bp_info);
- break;
+ if (unlikely(copy_from_user(&bp_info, datavp,
+ sizeof(struct ppc_hw_breakpoint)))
+ return -EFAULT;
+ return ppc_set_hwdebug(child, &bp_info);
}
case PPC_PTRACE_DELHWDEBUG: {
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH][RFC] [powerpc] arch_ptrace() uses of access_ok() are pointless
2018-05-27 22:34 [PATCH][RFC] [powerpc] arch_ptrace() uses of access_ok() are pointless Al Viro
@ 2018-05-28 19:25 ` Mathieu Malaterre
2018-05-28 20:30 ` Al Viro
0 siblings, 1 reply; 3+ messages in thread
From: Mathieu Malaterre @ 2018-05-28 19:25 UTC (permalink / raw)
To: Al Viro; +Cc: linuxppc-dev, LKML
On Mon, May 28, 2018 at 12:34 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> make it use copy_{from,to}_user(), rather than access_ok() +
> __copy_...
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
> arch/powerpc/kernel/ptrace.c | 22 +++++++---------------
> 1 file changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> index d23cf632edf0..d8b0fd2fa3aa 100644
> --- a/arch/powerpc/kernel/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace.c
> @@ -3081,27 +3081,19 @@ long arch_ptrace(struct task_struct *child, long =
request,
> #endif /* CONFIG_HAVE_HW_BREAKPOINT */
> #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
>
> - if (!access_ok(VERIFY_WRITE, datavp,
> - sizeof(struct ppc_debug_info)))
> + if (unlikely(copy_to_user(datavp, &dbginfo,
> + sizeof(struct ppc_debug_info)))
Maybe this is just an RFC, but:
CALL ../arch/powerpc/kernel/systbl_chk.sh
../arch/powerpc/kernel/ptrace.c: In function =E2=80=98arch_ptrace=E2=80=99:
../arch/powerpc/kernel/ptrace.c:3086:4: error: expected =E2=80=98)=E2=80=99=
before =E2=80=98return=E2=80=99
return -EFAULT;
^~~~~~
Missing closing parenthesis.
> return -EFAULT;
> - ret =3D __copy_to_user(datavp, &dbginfo,
> - sizeof(struct ppc_debug_info)) ?
> - -EFAULT : 0;
> - break;
> + return 0;
> }
>
> case PPC_PTRACE_SETHWDEBUG: {
> struct ppc_hw_breakpoint bp_info;
>
> - if (!access_ok(VERIFY_READ, datavp,
> - sizeof(struct ppc_hw_breakpoint)))
> - return -EFAULT;
> - ret =3D __copy_from_user(&bp_info, datavp,
> - sizeof(struct ppc_hw_breakpoint)) =
?
> - -EFAULT : 0;
> - if (!ret)
> - ret =3D ppc_set_hwdebug(child, &bp_info);
> - break;
> + if (unlikely(copy_from_user(&bp_info, datavp,
> + sizeof(struct ppc_hw_breakpoint)))
> + return -EFAULT;
> + return ppc_set_hwdebug(child, &bp_info);
> }
>
> case PPC_PTRACE_DELHWDEBUG: {
> --
> 2.11.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][RFC] [powerpc] arch_ptrace() uses of access_ok() are pointless
2018-05-28 19:25 ` Mathieu Malaterre
@ 2018-05-28 20:30 ` Al Viro
0 siblings, 0 replies; 3+ messages in thread
From: Al Viro @ 2018-05-28 20:30 UTC (permalink / raw)
To: Mathieu Malaterre; +Cc: linuxppc-dev, LKML
> Maybe this is just an RFC, but:
>
> CALL ../arch/powerpc/kernel/systbl_chk.sh
> ../arch/powerpc/kernel/ptrace.c: In function ‘arch_ptrace’:
> ../arch/powerpc/kernel/ptrace.c:3086:4: error: expected ‘)’ before ‘return’
> return -EFAULT;
> ^~~~~~
and the same a few lines later. What's more, those 'unlikely' are pointless
there. Fixed variant follows; only build-tested, though.
make it use copy_{from,to}_user(), rather than access_ok() +
__copy_...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/powerpc/kernel/ptrace.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index d23cf632edf0..f557322621e0 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -3081,27 +3081,19 @@ long arch_ptrace(struct task_struct *child, long request,
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
- if (!access_ok(VERIFY_WRITE, datavp,
- sizeof(struct ppc_debug_info)))
+ if (copy_to_user(datavp, &dbginfo,
+ sizeof(struct ppc_debug_info)))
return -EFAULT;
- ret = __copy_to_user(datavp, &dbginfo,
- sizeof(struct ppc_debug_info)) ?
- -EFAULT : 0;
- break;
+ return 0;
}
case PPC_PTRACE_SETHWDEBUG: {
struct ppc_hw_breakpoint bp_info;
- if (!access_ok(VERIFY_READ, datavp,
- sizeof(struct ppc_hw_breakpoint)))
- return -EFAULT;
- ret = __copy_from_user(&bp_info, datavp,
- sizeof(struct ppc_hw_breakpoint)) ?
- -EFAULT : 0;
- if (!ret)
- ret = ppc_set_hwdebug(child, &bp_info);
- break;
+ if (copy_from_user(&bp_info, datavp,
+ sizeof(struct ppc_hw_breakpoint)))
+ return -EFAULT;
+ return ppc_set_hwdebug(child, &bp_info);
}
case PPC_PTRACE_DELHWDEBUG: {
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2018-05-27 22:34 [PATCH][RFC] [powerpc] arch_ptrace() uses of access_ok() are pointless Al Viro
2018-05-28 19:25 ` Mathieu Malaterre
2018-05-28 20:30 ` Al Viro
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