linux-kernel - Re: [RFC PATCH v1 1/1] exec: seal system mappings

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241005200741.GA24353@redhat.com>
Date: Sat, 5 Oct 2024 22:08:05 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: jeffxu@...omium.org
Cc: akpm@...ux-foundation.org, keescook@...omium.org, jannh@...gle.com,
	torvalds@...ux-foundation.org, adhemerval.zanella@...aro.org,
	linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org,
	linux-mm@...ck.org, jorgelo@...omium.org, sroettger@...gle.com,
	ojeda@...nel.org, adobriyan@...il.com, anna-maria@...utronix.de,
	mark.rutland@....com, linus.walleij@...aro.org,
	mike.kravetz@...cle.com, Jason@...c4.com, deller@....de,
	rdunlap@...radead.org, davem@...emloft.net, hch@....de,
	peterx@...hat.com, hca@...ux.ibm.com, f.fainelli@...il.com,
	gerg@...nel.org, dave.hansen@...ux.intel.com, mingo@...nel.org,
	ardb@...nel.org, nathan_lynch@...tor.com, dsafonov@...tuozzo.com,
	Liam.Howlett@...cle.com, mhocko@...e.com, 42.hyeyoo@...il.com,
	peterz@...radead.org, ardb@...gle.com, enh@...gle.com,
	rientjes@...gle.com, groeck@...omium.org,
	lorenzo.stoakes@...cle.com
Subject: Re: [RFC PATCH v1 1/1] exec: seal system mappings

On 10/04, jeffxu@...omium.org wrote:
>
> It is important to note that the CHECKPOINT_RESTORE feature (CRIU) may
> alter the mapping of vdso, vvar, and sigpage during restore
> operations. Consequently, this feature cannot be universally enabled
> across all systems.

Can't review.

But as for uprobes, I'd prefer a simpler patch which doesn't need the new
CONFIG_ and/or kernel boot options, something like the patch below.

And I don't really like the fact that this patch changes the behaviour
of the "generic" _install_special_mapping() helper, but I won't argue.

Oleg.


--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -430,6 +430,8 @@ extern unsigned int kobjsize(const void *objp);
 #ifdef CONFIG_64BIT
 /* VM is sealed, in vm_flags */
 #define VM_SEALED	_BITUL(63)
+#else
+#define VM_SEALED	0
 #endif
 
 /* Bits set in the VMA until the stack is in its final location */
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 40ecab0971ff..388373c11593 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1510,7 +1510,7 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
 	}
 
 	vma = _install_special_mapping(mm, area->vaddr, PAGE_SIZE,
-				VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO,
+				VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO|VM_SEALED,
 				&xol_mapping);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);