Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Matt Redfearn]

On 01/04/16 09:44, Ralf Baechle wrote:

On Thu, Mar 31, 2016 at 03:38:10PM +0300, Sergei Shtylyov wrote:


When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.

Notifier.

Fixed when merging.


Signed-off-by: Matt Redfearn 
---

Changes in v2: None

  arch/mips/kernel/setup.c | 9 +
  1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);

offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)

Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?

[...]

CPP syntax is not what most people seem to believe that is the parenthesis
around the argument of defined are not required so above line is unusual
but perfectly ok.  However following boring standards is good so I changed
this, too.

   Ralf


Great, thanks Ralf.

Matt

Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Matt Redfearn]

On 01/04/16 09:44, Ralf Baechle wrote:

On Thu, Mar 31, 2016 at 03:38:10PM +0300, Sergei Shtylyov wrote:


When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.

Notifier.

Fixed when merging.


Signed-off-by: Matt Redfearn 
---

Changes in v2: None

  arch/mips/kernel/setup.c | 9 +
  1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);

offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)

Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?

[...]

CPP syntax is not what most people seem to believe that is the parenthesis
around the argument of defined are not required so above line is unusual
but perfectly ok.  However following boring standards is good so I changed
this, too.

   Ralf


Great, thanks Ralf.

Matt

Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Ralf Baechle]

On Thu, Mar 31, 2016 at 03:38:10PM +0300, Sergei Shtylyov wrote:

> >When debugging a relocated kernel, the addresses of the relocated
> >symbols and the offset applied is essential information. If the kernel
> >is compiled with debugging information, then print this information
> >during bootup using the same function as the panic notifer.
> 
>Notifier.

Fixed when merging.

> >Signed-off-by: Matt Redfearn 
> >---
> >
> >Changes in v2: None
> >
> >  arch/mips/kernel/setup.c | 9 +
> >  1 file changed, 9 insertions(+)
> >
> >diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> >index d8376d7b3345..ae71f8d9b555 100644
> >--- a/arch/mips/kernel/setup.c
> >+++ b/arch/mips/kernel/setup.c
> >@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
> >  */
> > if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
> > unsigned long offset;
> >+extern void show_kernel_relocation(const char *level);
> >
> > offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
> > free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
> >+
> >+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)
> 
>Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?
> 
> [...]

CPP syntax is not what most people seem to believe that is the parenthesis
around the argument of defined are not required so above line is unusual
but perfectly ok.  However following boring standards is good so I changed
this, too.

  Ralf

Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Ralf Baechle]

On Thu, Mar 31, 2016 at 03:38:10PM +0300, Sergei Shtylyov wrote:

> >When debugging a relocated kernel, the addresses of the relocated
> >symbols and the offset applied is essential information. If the kernel
> >is compiled with debugging information, then print this information
> >during bootup using the same function as the panic notifer.
> 
>Notifier.

Fixed when merging.

> >Signed-off-by: Matt Redfearn 
> >---
> >
> >Changes in v2: None
> >
> >  arch/mips/kernel/setup.c | 9 +
> >  1 file changed, 9 insertions(+)
> >
> >diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> >index d8376d7b3345..ae71f8d9b555 100644
> >--- a/arch/mips/kernel/setup.c
> >+++ b/arch/mips/kernel/setup.c
> >@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
> >  */
> > if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
> > unsigned long offset;
> >+extern void show_kernel_relocation(const char *level);
> >
> > offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
> > free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
> >+
> >+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)
> 
>Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?
> 
> [...]

CPP syntax is not what most people seem to believe that is the parenthesis
around the argument of defined are not required so above line is unusual
but perfectly ok.  However following boring standards is good so I changed
this, too.

  Ralf

Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Sergei Shtylyov]

Hello.

On 3/31/2016 12:05 PM, Matt Redfearn wrote:


When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.


   Notifier.


Signed-off-by: Matt Redfearn 
---

Changes in v2: None

  arch/mips/kernel/setup.c | 9 +
  1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);

offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)


   Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?

[...]

MBR, Sergei

Re: [PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Sergei Shtylyov]

Hello.

On 3/31/2016 12:05 PM, Matt Redfearn wrote:


When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.


   Notifier.


Signed-off-by: Matt Redfearn 
---

Changes in v2: None

  arch/mips/kernel/setup.c | 9 +
  1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);

offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)


   Not #if defined(CONFIG_DEBUG_KERNEL) && defined(CONFIG_DEBUG_INFO)?

[...]

MBR, Sergei

[PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Matt Redfearn]

When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.

Signed-off-by: Matt Redfearn 
---

Changes in v2: None

 arch/mips/kernel/setup.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);
 
offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)
+   /*
+* This information is necessary when debugging the kernel
+* But is a security vulnerability otherwise!
+*/
+   show_kernel_relocation(KERN_INFO);
+#endif
}
 #endif
 
-- 
2.5.0

[PATCH v2 11/11] MIPS: KASLR: Print relocation Information on boot

[Matt Redfearn]

When debugging a relocated kernel, the addresses of the relocated
symbols and the offset applied is essential information. If the kernel
is compiled with debugging information, then print this information
during bootup using the same function as the panic notifer.

Signed-off-by: Matt Redfearn 
---

Changes in v2: None

 arch/mips/kernel/setup.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index d8376d7b3345..ae71f8d9b555 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -477,9 +477,18 @@ static void __init bootmem_init(void)
 */
if (__pa_symbol(_text) > __pa_symbol(VMLINUX_LOAD_ADDRESS)) {
unsigned long offset;
+   extern void show_kernel_relocation(const char *level);
 
offset = __pa_symbol(_text) - __pa_symbol(VMLINUX_LOAD_ADDRESS);
free_bootmem(__pa_symbol(VMLINUX_LOAD_ADDRESS), offset);
+
+#if (defined CONFIG_DEBUG_KERNEL) && (defined CONFIG_DEBUG_INFO)
+   /*
+* This information is necessary when debugging the kernel
+* But is a security vulnerability otherwise!
+*/
+   show_kernel_relocation(KERN_INFO);
+#endif
}
 #endif
 
-- 
2.5.0