Messages in this thread Patch in this message | | | Subject | RE: [PATCH 1/2] setup_arg_pages can insert overlapping vma | Date | Wed, 24 Nov 2004 09:04:28 +0800 | From | "Zou, Nanhai" <> |
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<<ia64-vm-overlap.tar.gz>> <<vma-overlap-fix.patch>> I think ia64 ia32 subsystem is not vulnerable to this kind of overlapping vm problem, because it does not support a.out binary format, X84_64 is vulnerable to this.
just do a perl -e'print"\x07\x01".("\x00"x10)."\x00\xe0\xff\xff".("\x00"x16)'> evilaout you will get it.
and IA64 is also vulnerable to this kind of bug in 64 bit elf support, it just insert a vma of zero page without checking overlap, so user can construct a elf with section begin from 0x0 to trigger this BUGON().I attach a testcase to trigger this bug I don't know what about s390. However, I think it's safe to check overlap before we actually insert a vma into vma list.
And I also feel check vma overlap everywhere is unnecessary, because invert_vm_struct will check it again, so the check is duplicated. It's better to have invert_vm_struct return a value then let caller check if it successes. Here is a patch against 2.6.10.rc2-mm3 I have tested it on i386, x86_64 and ia64 machines.
Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Zou Nan hai <Nanhai.zou@intel.com>
-----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Hugh Dickins Sent: Friday, November 19, 2004 1:40 AM To: Chris Wright Cc: Andrew Morton; Linus Torvalds; Luck, Tony; Martin Schwidefsky; Andi Kleen; linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] setup_arg_pages can insert overlapping vma
On Tue, 16 Nov 2004, Chris Wright wrote: > Florian Heinz built an a.out binary that could map bss from 0x0 to > 0xc0000000, and setup_arg_pages() would BUG() in insert_vma_struct > because the arg pages overlapped. This just checks before inserting, > and bails out if it would overlap.
Chris, shouldn't your patch also cover the setup_arg_pages clones for 32-bit support on 64-bit architectures, with something - uncompiled, untested - like the below? I'm not sure how necessary the additional vma->vm_start < mpnt->vm_end test is, but suspect ia64 might need it.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
--- 2.6.10-rc2-bk2/arch/ia64/ia32/binfmt_elf32.c 2004-10-18 22:57:03.000000000 +0100 +++ linux/arch/ia64/ia32/binfmt_elf32.c 2004-11-18 17:17:57.000000000 +0000 @@ -214,6 +214,8 @@ ia32_setup_arg_pages (struct linux_binpr down_write(¤t->mm->mmap_sem); { + struct vm_area_struct *vma; + mpnt->vm_mm = current->mm; mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p; mpnt->vm_end = IA32_STACK_TOP; @@ -225,6 +227,12 @@ ia32_setup_arg_pages (struct linux_binpr mpnt->vm_flags = VM_STACK_FLAGS; mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)? PAGE_COPY_EXEC: PAGE_COPY; + vma = find_vma(current->mm, mpnt->vm_start); + if (vma && vma->vm_start < mpnt->vm_end) { + up_write(¤t->mm->mmap_sem); + kmem_cache_free(vm_area_cachep, mpnt); + return -ENOMEM; + } insert_vm_struct(current->mm, mpnt); current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt); } --- 2.6.10-rc2-bk2/arch/s390/kernel/compat_exec.c 2004-10-18 22:56:50.000000000 +0100 +++ linux/arch/s390/kernel/compat_exec.c 2004-11-18 17:17:57.000000000 +0000 @@ -62,12 +62,20 @@ int setup_arg_pages32(struct linux_binpr down_write(&mm->mmap_sem); { + struct vm_area_struct *vma; + mpnt->vm_mm = mm; mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p; mpnt->vm_end = STACK_TOP; /* executable stack setting would be applied here */ mpnt->vm_page_prot = PAGE_COPY; mpnt->vm_flags = VM_STACK_FLAGS; + vma = find_vma(mm, mpnt->vm_start); + if (vma && vma->vm_start < mpnt->vm_end) { + up_write(&mm->mmap_sem); + kmem_cache_free(vm_area_cachep, mpnt); + return -ENOMEM; + } insert_vm_struct(mm, mpnt); mm->stack_vm = mm->total_vm = vma_pages(mpnt); } --- 2.6.10-rc2-bk2/arch/x86_64/ia32/ia32_binfmt.c 2004-11-15 16:20:34.000000000 +0000 +++ linux/arch/x86_64/ia32/ia32_binfmt.c 2004-11-18 17:17:57.000000000 +0000 @@ -357,6 +357,8 @@ int setup_arg_pages(struct linux_binprm down_write(&mm->mmap_sem); { + struct vm_area_struct *vma; + mpnt->vm_mm = mm; mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p; mpnt->vm_end = IA32_STACK_TOP; @@ -368,6 +370,12 @@ int setup_arg_pages(struct linux_binprm mpnt->vm_flags = VM_STACK_FLAGS; mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC) ? PAGE_COPY_EXEC : PAGE_COPY; + vma = find_vma(mm, mpnt->vm_start); + if (vma && vma->vm_start < mpnt->vm_end) { + up_write(&mm->mmap_sem); + kmem_cache_free(vm_area_cachep, mpnt); + return -ENOMEM; + } insert_vm_struct(mm, mpnt); mm->stack_vm = mm->total_vm = vma_pages(mpnt); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ [unhandled content-type:application/x-gzip][unhandled content-type:application/octet-stream] | |