linux-kernel - [BUGFIX] kvm, Fix a race condition for usage of is_hwpoison

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 for Android: free password hash cracker in your pocket

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

Message-ID: <1277187791.3004.149.camel@yhuang-dev.sh.intel.com>
Date:	Tue, 22 Jun 2010 14:23:11 +0800
From:	Huang Ying <ying.huang@...el.com>
To:	Avi Kivity <avi@...hat.com>
Cc:	Andi Kleen <ak@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: [BUGFIX] kvm, Fix a race condition for usage of is_hwpoison_address

is_hwpoison_address accesses the page table, so the caller must hold
current->mm->mmap_sem in read mode. So fix its usage in hav_to_pfn of
kvm accordingly.

Comments on is_hwpoison_address are added to remind other users.

Reported-by: Avi Kivity <avi@...hat.com>
Signed-off-by: Huang Ying <ying.huang@...el.com>
---
 mm/memory-failure.c |    3 +++
 virt/kvm/kvm_main.c |    3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1298,6 +1298,9 @@ done:
 	return ret;
 }
 
+/*
+ * The caller must hold current->mm->mmap_sem in read mode.
+ */
 int is_hwpoison_address(unsigned long addr)
 {
 	pgd_t *pgdp;
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -955,12 +955,13 @@ static pfn_t hva_to_pfn(struct kvm *kvm,
 	if (unlikely(npages != 1)) {
 		struct vm_area_struct *vma;
 
+		down_read(&current->mm->mmap_sem);
 		if (is_hwpoison_address(addr)) {
+			up_read(&current->mm->mmap_sem);
 			get_page(hwpoison_page);
 			return page_to_pfn(hwpoison_page);
 		}
 
-		down_read(&current->mm->mmap_sem);
 		vma = find_vma(current->mm, addr);
 
 		if (vma == NULL || addr < vma->vm_start ||


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/