linux-kernel - [PATCH 2/4] uprobes: fix register_for_each_vma()->vma

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: <20120712171020.GA25500@redhat.com>
Date:	Thu, 12 Jul 2012 19:10:20 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>,
	Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] uprobes: fix register_for_each_vma()->vma_address()
	check

1. register_for_each_vma() checks that vma_address() == vaddr but
   this is not enough. We should also ensure that vaddr >= vm_start,
   find_vma() guarantees "vaddr < vm_end" only.

2. After the prevous changes, register_for_each_vma() is the only
   reason why vma_address() has to return loff_t, all other users
   know that we have the valid mapping at this offset and thus the
   overflow is not possible.

   Change the code to use vaddr_to_offset() instead, imho this looks
   more clean/understandable and now we can change vma_address().

3. While at it, remove the unnecessary type-cast.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/events/uprobes.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5c87042..734e199 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -823,12 +823,13 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
 			goto free;
 
 		down_write(&mm->mmap_sem);
-		vma = find_vma(mm, (unsigned long)info->vaddr);
-		if (!vma || !valid_vma(vma, is_register))
+		vma = find_vma(mm, info->vaddr);
+		if (!vma || !valid_vma(vma, is_register) ||
+		    vma->vm_file->f_mapping->host != uprobe->inode)
 			goto unlock;
 
-		if (vma->vm_file->f_mapping->host != uprobe->inode ||
-		    vma_address(vma, uprobe->offset) != info->vaddr)
+		if (vma->vm_start > info->vaddr ||
+		    vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
 			goto unlock;
 
 		if (is_register) {
-- 
1.5.5.1

--
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/