linux-kernel - [PATCH v2 1/5] uprobes: don't recheck vma/f_mapping in write

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: <20120624150002.GA23277@redhat.com>
Date:	Sun, 24 Jun 2012 17:00:02 +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 v2 1/5] uprobes: don't recheck vma/f_mapping in
	write_opcode()

write_opcode() rechecks valid_vma() and ->f_mapping, this is pointless.
The caller, register_for_each_vma() or uprobe_mmap(), has already done
these checks under mmap_sem.

To clarify, uprobe_mmap() checks valid_vma() only, but we can rely on
build_probe_list(vm_file->f_mapping->host).

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/events/uprobes.c |   19 +------------------
 1 files changed, 1 insertions(+), 18 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f935327..a2b32a5 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -206,33 +206,16 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 			unsigned long vaddr, uprobe_opcode_t opcode)
 {
 	struct page *old_page, *new_page;
-	struct address_space *mapping;
 	void *vaddr_old, *vaddr_new;
 	struct vm_area_struct *vma;
-	struct uprobe *uprobe;
 	int ret;
+
 retry:
 	/* Read the page with vaddr into memory */
 	ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma);
 	if (ret <= 0)
 		return ret;
 
-	ret = -EINVAL;
-
-	/*
-	 * We are interested in text pages only. Our pages of interest
-	 * should be mapped for read and execute only. We desist from
-	 * adding probes in write mapped pages since the breakpoints
-	 * might end up in the file copy.
-	 */
-	if (!valid_vma(vma, is_swbp_insn(&opcode)))
-		goto put_out;
-
-	uprobe = container_of(auprobe, struct uprobe, arch);
-	mapping = uprobe->inode->i_mapping;
-	if (mapping != vma->vm_file->f_mapping)
-		goto put_out;
-
 	ret = -ENOMEM;
 	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
 	if (!new_page)
-- 
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/