Re: [PATCH 1/3] mmap: protect from stack expantion into low vm addresses
On Mon, 26 Nov 2007, Eric Paris wrote:
> Add security checks to make sure we are not attempting to expand the
> stack into memory protected by mmap_min_addr
>
> Signed-off-by: Eric Paris <[EMAIL PROTECTED]>
Please include the LSMs list in the CC line (added again) for posts
relating to security.
Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6.git#for-akpm
> ---
>
> ** Be very careful applying/rediffing this patch. Standard 3 lines of
> context from git diff will misapply the first hunk to expand_upwards
> instead of properly in expand_downwards. This patch was generated using
> -U 4 to make sure it applies in the correct place. **
Seems to have applied correctly for me.
>
> mm/mmap.c |8 ++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> --- kernel-1/mm/mmap.c
> +++ kernel-2/mm/mmap.c
> @@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
>* so that the anon_vma locking is not a noop.
>*/
> if (unlikely(anon_vma_prepare(vma)))
> return -ENOMEM;
> +
> + address &= PAGE_MASK;
> + error = security_file_mmap(0, 0, 0, 0, address, 1);
> + if (error)
> + return error;
> +
> anon_vma_lock(vma);
>
> /*
>* vma->vm_start/vm_end cannot change under us because the caller
>* is required to hold the mmap_sem in read mode. We need the
>* anon_vma lock to serialize against concurrent expand_stacks.
>*/
> - address &= PAGE_MASK;
> - error = 0;
>
> /* Somebody else might have raced and expanded it already */
> if (address < vma->vm_start) {
> unsigned long size, grow;
>
>
--
James Morris
<[EMAIL PROTECTED]>
-
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[PATCH 1/3] mmap: protect from stack expantion into low vm addresses
Add security checks to make sure we are not attempting to expand the
stack into memory protected by mmap_min_addr
Signed-off-by: Eric Paris <[EMAIL PROTECTED]>
---
** Be very careful applying/rediffing this patch. Standard 3 lines of
context from git diff will misapply the first hunk to expand_upwards
instead of properly in expand_downwards. This patch was generated using
-U 4 to make sure it applies in the correct place. **
mm/mmap.c |8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c
+++ kernel-2/mm/mmap.c
@@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
* so that the anon_vma locking is not a noop.
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address &= PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address &= PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address < vma->vm_start) {
unsigned long size, grow;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/3] mmap: protect from stack expantion into low vm addresses
Add security checks to make sure we are not attempting to expand the
stack into memory protected by mmap_min_addr
Signed-off-by: Eric Paris [EMAIL PROTECTED]
---
** Be very careful applying/rediffing this patch. Standard 3 lines of
context from git diff will misapply the first hunk to expand_upwards
instead of properly in expand_downwards. This patch was generated using
-U 4 to make sure it applies in the correct place. **
mm/mmap.c |8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c
+++ kernel-2/mm/mmap.c
@@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
* so that the anon_vma locking is not a noop.
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address = PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
* vma-vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address = PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address vma-vm_start) {
unsigned long size, grow;
-
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the body of a message to [EMAIL PROTECTED]
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/3] mmap: protect from stack expantion into low vm addresses
On Mon, 26 Nov 2007, Eric Paris wrote:
Add security checks to make sure we are not attempting to expand the
stack into memory protected by mmap_min_addr
Signed-off-by: Eric Paris [EMAIL PROTECTED]
Please include the LSMs list in the CC line (added again) for posts
relating to security.
Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6.git#for-akpm
---
** Be very careful applying/rediffing this patch. Standard 3 lines of
context from git diff will misapply the first hunk to expand_upwards
instead of properly in expand_downwards. This patch was generated using
-U 4 to make sure it applies in the correct place. **
Seems to have applied correctly for me.
mm/mmap.c |8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c
+++ kernel-2/mm/mmap.c
@@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
* so that the anon_vma locking is not a noop.
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address = PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
* vma-vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address = PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address vma-vm_start) {
unsigned long size, grow;
--
James Morris
[EMAIL PROTECTED]
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/3] mmap: protect from stack expantion into low vm addresses
When adding the new security hooks into mmap to enhance protection
against NULL pointers in the kernel I overlooked that a user may be able
to expand the stack all the way down to low addresses. This flaw was
pointed out by a PaX/grsecurity developer and this patch should provide
protection against this missed code path.
Signed-off-by: Eric Paris <[EMAIL PROTECTED]>
---
** Be very careful applying/rediffing this patch. Standard 3 lines of
context from git diff will misapply the first hunk to expand_upwards
instead of properly in expand_downwards. This patch was generated using
-U 4 to make sure it applies in the correct place. **
mm/mmap.c |8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c
+++ kernel-2/mm/mmap.c
@@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
* so that the anon_vma locking is not a noop.
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address &= PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
* vma->vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address &= PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address < vma->vm_start) {
unsigned long size, grow;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/3] mmap: protect from stack expantion into low vm addresses
When adding the new security hooks into mmap to enhance protection
against NULL pointers in the kernel I overlooked that a user may be able
to expand the stack all the way down to low addresses. This flaw was
pointed out by a PaX/grsecurity developer and this patch should provide
protection against this missed code path.
Signed-off-by: Eric Paris [EMAIL PROTECTED]
---
** Be very careful applying/rediffing this patch. Standard 3 lines of
context from git diff will misapply the first hunk to expand_upwards
instead of properly in expand_downwards. This patch was generated using
-U 4 to make sure it applies in the correct place. **
mm/mmap.c |8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- kernel-1/mm/mmap.c
+++ kernel-2/mm/mmap.c
@@ -1614,17 +1614,21 @@ static inline int expand_downwards(struc
* so that the anon_vma locking is not a noop.
*/
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
+
+ address = PAGE_MASK;
+ error = security_file_mmap(0, 0, 0, 0, address, 1);
+ if (error)
+ return error;
+
anon_vma_lock(vma);
/*
* vma-vm_start/vm_end cannot change under us because the caller
* is required to hold the mmap_sem in read mode. We need the
* anon_vma lock to serialize against concurrent expand_stacks.
*/
- address = PAGE_MASK;
- error = 0;
/* Somebody else might have raced and expanded it already */
if (address vma-vm_start) {
unsigned long size, grow;
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
