From: Siddha, Suresh B <suresh.b.siddha@intel.com>
Date: Sat, 16 Jul 2005 02:17:44 +0000 (-0700)
Subject: [PATCH] x86_64: TASK_SIZE fixes for compatibility mode processes
X-Git-Tag: v3.12-rc1~43125
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9fb1759a3102c26cd8f64254a7c3e532782c2bb8;p=kernel%2Fkernel-generic.git

[PATCH] x86_64: TASK_SIZE fixes for compatibility mode processes

A malicious 32bit app can have an elf section at 0xffffe000.  During
exec of this app, we will have a memory leak as insert_vm_struct() is
not checking for return value in syscall32_setup_pages() and thus not
freeing the vma allocated for the vsyscall page.

Check the return value and free the vma incase of failure.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index 01d8db1..816a3b8 100644
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -57,6 +57,7 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
 	int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;
+	int ret;
 
 	vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 	if (!vma)
@@ -78,7 +79,11 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
 	vma->vm_mm = mm;
 
 	down_write(&mm->mmap_sem);
-	insert_vm_struct(mm, vma);
+	if ((ret = insert_vm_struct(mm, vma))) {
+		up_write(&mm->mmap_sem);
+		kmem_cache_free(vm_area_cachep, vma);
+		return ret;
+	}
 	mm->total_vm += npages;
 	up_write(&mm->mmap_sem);
 	return 0;