Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> + offset = addr & PAGE_MASK;

Should be addr & ~PAGE_MASK. Had fixup for this but it ended up not be
squashed to the series :-(

/Jarkko

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> + offset = addr & PAGE_MASK;

Should be addr & ~PAGE_MASK. Had fixup for this but it ended up not be
squashed to the series :-(

/Jarkko

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sun, Nov 26, 2017 at 07:50:05AM -0800, Joe Perches wrote:
> On Sun, 2017-11-26 at 17:44 +0200, Jarkko Sakkinen wrote:
> > On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> > > + ptr = sgx_get_page(page->epc_page);
> > > + ret = __edbgrd((unsigned long)ptr + offset, data);
>   ^^
> 
> > > + sgx_put_page(ptr);
> > > + if (ret) {
> > > + sgx_dbg(encl, "EDBGRD returned %d\n", ret);
> >~~
> >EDBGWR
> 
> ?

D'oh I meant to quote this part:

ptr = sgx_get_page(page->epc_page);
ret = __edbgwr((unsigned long)ptr + offset, data);
sgx_put_page(ptr);
if (ret) {
sgx_dbg(encl, "EDBGRD returned %d\n", ret);
return -EFAULT;
}

There's a typo in sgx_dbg().

/Jarkko

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sun, Nov 26, 2017 at 07:50:05AM -0800, Joe Perches wrote:
> On Sun, 2017-11-26 at 17:44 +0200, Jarkko Sakkinen wrote:
> > On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> > > + ptr = sgx_get_page(page->epc_page);
> > > + ret = __edbgrd((unsigned long)ptr + offset, data);
>   ^^
> 
> > > + sgx_put_page(ptr);
> > > + if (ret) {
> > > + sgx_dbg(encl, "EDBGRD returned %d\n", ret);
> >~~
> >EDBGWR
> 
> ?

D'oh I meant to quote this part:

ptr = sgx_get_page(page->epc_page);
ret = __edbgwr((unsigned long)ptr + offset, data);
sgx_put_page(ptr);
if (ret) {
sgx_dbg(encl, "EDBGRD returned %d\n", ret);
return -EFAULT;
}

There's a typo in sgx_dbg().

/Jarkko

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Joe Perches]

On Sun, 2017-11-26 at 17:44 +0200, Jarkko Sakkinen wrote:
> On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> > +   ptr = sgx_get_page(page->epc_page);
> > +   ret = __edbgrd((unsigned long)ptr + offset, data);
^^

> > +   sgx_put_page(ptr);
> > +   if (ret) {
> > +   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
>~~
>  EDBGWR

?

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Joe Perches]

On Sun, 2017-11-26 at 17:44 +0200, Jarkko Sakkinen wrote:
> On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> > +   ptr = sgx_get_page(page->epc_page);
> > +   ret = __edbgrd((unsigned long)ptr + offset, data);
^^

> > +   sgx_put_page(ptr);
> > +   if (ret) {
> > +   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
>~~
>  EDBGWR

?

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> + ptr = sgx_get_page(page->epc_page);
> + ret = __edbgrd((unsigned long)ptr + offset, data);
> + sgx_put_page(ptr);
> + if (ret) {
> + sgx_dbg(encl, "EDBGRD returned %d\n", ret);
   ~~
   EDBGWR

/Jarkko

Re: [PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

On Sat, Nov 25, 2017 at 09:29:24PM +0200, Jarkko Sakkinen wrote:
> + ptr = sgx_get_page(page->epc_page);
> + ret = __edbgrd((unsigned long)ptr + offset, data);
> + sgx_put_page(ptr);
> + if (ret) {
> + sgx_dbg(encl, "EDBGRD returned %d\n", ret);
   ~~
   EDBGWR

/Jarkko

[PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

Implemented VMA callbacks in order to ptrace() debug enclaves. With
debug enclaves data can be read and write the memory word at a time by
using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.

Signed-off-by: Jarkko Sakkinen 
---
 drivers/platform/x86/intel_sgx/sgx_vma.c | 119 +++
 1 file changed, 119 insertions(+)

diff --git a/drivers/platform/x86/intel_sgx/sgx_vma.c 
b/drivers/platform/x86/intel_sgx/sgx_vma.c
index 481f671f10ca..a8f58ea65dd5 100644
--- a/drivers/platform/x86/intel_sgx/sgx_vma.c
+++ b/drivers/platform/x86/intel_sgx/sgx_vma.c
@@ -110,8 +110,127 @@ static int sgx_vma_fault(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
 }
 
+static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+   unsigned long offset;
+   void *ptr;
+   int ret;
+
+   offset = addr & PAGE_MASK;
+
+   if ((page->flags & SGX_ENCL_PAGE_TCS) &&
+   (offset + sizeof(unsigned long)) >
+   offsetof(struct sgx_tcs, reserved))
+   return -ECANCELED;
+
+   ptr = sgx_get_page(page->epc_page);
+   ret = __edbgrd((unsigned long)ptr + offset, data);
+   sgx_put_page(ptr);
+   if (ret) {
+   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+   return -EFAULT;
+   }
+
+   return 0;
+}
+
+static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+   unsigned long offset;
+   void *ptr;
+   int ret;
+
+   offset = addr & PAGE_MASK;
+
+   /* Writing anything else than flags will cause #GP */
+   if ((page->flags & SGX_ENCL_PAGE_TCS) &&
+   offset < offsetof(struct sgx_tcs, flags) &&
+   (offset + sizeof(unsigned long)) >
+   offsetof(struct sgx_tcs, flags))
+   return -ECANCELED;
+
+   ptr = sgx_get_page(page->epc_page);
+   ret = __edbgwr((unsigned long)ptr + offset, data);
+   sgx_put_page(ptr);
+   if (ret) {
+   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+   return -EFAULT;
+   }
+
+   return 0;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+   struct sgx_encl *encl = vma->vm_private_data;
+   struct sgx_encl_page *entry = NULL;
+   unsigned long align;
+   char data[sizeof(unsigned long)];
+   int offset;
+   int cnt;
+   int ret = 0;
+   int i;
+
+   /* If process was forked, VMA is still there but vm_private_data is set
+* to NULL.
+*/
+   if (!encl)
+   return -EFAULT;
+
+   if (!(encl->flags & SGX_ENCL_DEBUG) ||
+   !(encl->flags & SGX_ENCL_INITIALIZED) ||
+   (encl->flags & SGX_ENCL_DEAD))
+   return -EFAULT;
+
+   for (i = 0; i < len; i += cnt) {
+   if (!entry || !((addr + i) & (PAGE_SIZE - 1))) {
+   if (entry)
+   entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+   entry = sgx_fault_page(vma, (addr + i) & PAGE_MASK,
+  SGX_FAULT_RESERVE);
+   if (IS_ERR(entry)) {
+   ret = PTR_ERR(entry);
+   entry = NULL;
+   break;
+   }
+   }
+
+   /* Locking is not needed because only immutable fields of the
+* page are accessed and page itself is reserved so that it
+* cannot be swapped out in the middle.
+*/
+
+   align = ALIGN_DOWN(addr + i, sizeof(unsigned long));
+   offset = (addr + i) & (sizeof(unsigned long) - 1);
+   cnt = sizeof(unsigned long) - offset;
+   cnt = min(cnt, len - i);
+
+   ret = sgx_edbgrd(encl, entry, align, data);
+   if (ret)
+   return ret;
+
+   memcpy(data + offset, buf + i, cnt);
+
+   if (write) {
+   ret = sgx_edbgwr(encl, entry, align, data);
+   if (ret)
+   return ret;
+   }
+   }
+
+   if (entry)
+   entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+   return (ret < 0 && ret != -ECANCELED) ? ret : i;
+}
+
 const struct vm_operations_struct sgx_vm_ops = {
.close = sgx_vma_close,
.open = sgx_vma_open,
.fault = sgx_vma_fault,
+   .access = sgx_vma_access,
 };
-- 
2.14.1

[PATCH v6 07/11] intel_sgx: ptrace() support

[Jarkko Sakkinen]

Implemented VMA callbacks in order to ptrace() debug enclaves. With
debug enclaves data can be read and write the memory word at a time by
using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.

Signed-off-by: Jarkko Sakkinen 
---
 drivers/platform/x86/intel_sgx/sgx_vma.c | 119 +++
 1 file changed, 119 insertions(+)

diff --git a/drivers/platform/x86/intel_sgx/sgx_vma.c 
b/drivers/platform/x86/intel_sgx/sgx_vma.c
index 481f671f10ca..a8f58ea65dd5 100644
--- a/drivers/platform/x86/intel_sgx/sgx_vma.c
+++ b/drivers/platform/x86/intel_sgx/sgx_vma.c
@@ -110,8 +110,127 @@ static int sgx_vma_fault(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
 }
 
+static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+   unsigned long offset;
+   void *ptr;
+   int ret;
+
+   offset = addr & PAGE_MASK;
+
+   if ((page->flags & SGX_ENCL_PAGE_TCS) &&
+   (offset + sizeof(unsigned long)) >
+   offsetof(struct sgx_tcs, reserved))
+   return -ECANCELED;
+
+   ptr = sgx_get_page(page->epc_page);
+   ret = __edbgrd((unsigned long)ptr + offset, data);
+   sgx_put_page(ptr);
+   if (ret) {
+   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+   return -EFAULT;
+   }
+
+   return 0;
+}
+
+static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+   unsigned long offset;
+   void *ptr;
+   int ret;
+
+   offset = addr & PAGE_MASK;
+
+   /* Writing anything else than flags will cause #GP */
+   if ((page->flags & SGX_ENCL_PAGE_TCS) &&
+   offset < offsetof(struct sgx_tcs, flags) &&
+   (offset + sizeof(unsigned long)) >
+   offsetof(struct sgx_tcs, flags))
+   return -ECANCELED;
+
+   ptr = sgx_get_page(page->epc_page);
+   ret = __edbgwr((unsigned long)ptr + offset, data);
+   sgx_put_page(ptr);
+   if (ret) {
+   sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+   return -EFAULT;
+   }
+
+   return 0;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+   struct sgx_encl *encl = vma->vm_private_data;
+   struct sgx_encl_page *entry = NULL;
+   unsigned long align;
+   char data[sizeof(unsigned long)];
+   int offset;
+   int cnt;
+   int ret = 0;
+   int i;
+
+   /* If process was forked, VMA is still there but vm_private_data is set
+* to NULL.
+*/
+   if (!encl)
+   return -EFAULT;
+
+   if (!(encl->flags & SGX_ENCL_DEBUG) ||
+   !(encl->flags & SGX_ENCL_INITIALIZED) ||
+   (encl->flags & SGX_ENCL_DEAD))
+   return -EFAULT;
+
+   for (i = 0; i < len; i += cnt) {
+   if (!entry || !((addr + i) & (PAGE_SIZE - 1))) {
+   if (entry)
+   entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+   entry = sgx_fault_page(vma, (addr + i) & PAGE_MASK,
+  SGX_FAULT_RESERVE);
+   if (IS_ERR(entry)) {
+   ret = PTR_ERR(entry);
+   entry = NULL;
+   break;
+   }
+   }
+
+   /* Locking is not needed because only immutable fields of the
+* page are accessed and page itself is reserved so that it
+* cannot be swapped out in the middle.
+*/
+
+   align = ALIGN_DOWN(addr + i, sizeof(unsigned long));
+   offset = (addr + i) & (sizeof(unsigned long) - 1);
+   cnt = sizeof(unsigned long) - offset;
+   cnt = min(cnt, len - i);
+
+   ret = sgx_edbgrd(encl, entry, align, data);
+   if (ret)
+   return ret;
+
+   memcpy(data + offset, buf + i, cnt);
+
+   if (write) {
+   ret = sgx_edbgwr(encl, entry, align, data);
+   if (ret)
+   return ret;
+   }
+   }
+
+   if (entry)
+   entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+   return (ret < 0 && ret != -ECANCELED) ? ret : i;
+}
+
 const struct vm_operations_struct sgx_vm_ops = {
.close = sgx_vma_close,
.open = sgx_vma_open,
.fault = sgx_vma_fault,
+   .access = sgx_vma_access,
 };
-- 
2.14.1