[tip:x86/ptrace] x86, ptrace: Prepare regset get/set routines for user specified lengths

tip-bot for Suresh Siddha
2010-02-09T22:55:32Z

Commit-ID: a6bf9383255e088f5a78d93e2f8cd871aa028060
Gitweb: http://git.kernel.org/tip/a6bf9383255e088f5a78d93e2f8cd871aa028060
Author: Suresh Siddha <suresh.b.siddha@intel.com>
AuthorDate: Tue, 9 Feb 2010 12:13:12 -0800
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Tue, 9 Feb 2010 14:09:58 -0800

x86, ptrace: Prepare regset get/set routines for user specified lengths

Prepare the x86 regset routines for the upcoming generic
PTRACE_GETREGSET/PTRACE_SETREGSET commands. These commands allow the user
to specify how much to read and hence the kernel needs to ensure that
the get/set routines of the regset don't allow the user to access more kernel
buffers than needed.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100209202502.310242237@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/x86/kernel/i387.c | 15 ++++++++++-----
1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 4719bf9..23efdef 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -184,6 +184,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
void *kbuf, void __user *ubuf)
{
int ret;
+ int size = regset->n * regset->size;

if (!cpu_has_fxsr)
return -ENODEV;
@@ -193,7 +194,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
return ret;

return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->fxsave, 0, -1);
+ &target->thread.xstate->fxsave, 0, size);
}

int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
@@ -201,6 +202,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
const void *kbuf, const void __user *ubuf)
{
int ret;
+ int size = regset->n * regset->size;

if (!cpu_has_fxsr)
return -ENODEV;
@@ -210,7 +212,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
return ret;

ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->fxsave, 0, -1);
+ &target->thread.xstate->fxsave, 0, size);

/*
* mxcsr reserved bits must be masked to zero for security reasons.
@@ -452,6 +454,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
void *kbuf, void __user *ubuf)
{
struct user_i387_ia32_struct env;
+ int size = regset->n * regset->size;
int ret;

ret = init_fpu(target);
@@ -464,7 +467,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_fxsr) {
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->fsave, 0,
- -1);
+ size);
}

if (kbuf && pos == 0 && count == sizeof(env)) {
@@ -482,6 +485,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
const void *kbuf, const void __user *ubuf)
{
struct user_i387_ia32_struct env;
+ int size = regset->n * regset->size;
int ret;

ret = init_fpu(target);
@@ -495,13 +499,14 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,

if (!cpu_has_fxsr) {
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
- &target->thread.xstate->fsave, 0, -1);
+ &target->thread.xstate->fsave, 0,
+ size);
}

if (pos > 0 || count < sizeof(env))
convert_from_fxsr(&env, target);

- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, size);
if (!ret)
convert_to_fxsr(target, &env);