[tip:perf/core] uprobes: Fix overflow in vma_address()/find_active_uprobe()

[tip-bot for Oleg Nesterov]

Commit-ID:  aefd8933d445abf7ff0d4027c624737898827bcd
Gitweb:     http://git.kernel.org/tip/aefd8933d445abf7ff0d4027c624737898827bcd
Author:     Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sun, 29 Jul 2012 20:22:33 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 30 Jul 2012 11:27:21 +0200

uprobes: Fix overflow in vma_address()/find_active_uprobe()

vma->vm_pgoff is "unsigned long", it should be promoted to
loff_t before the multiplication to avoid the overflow.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
Cc: Anton Arapov <anton@xxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20120729182233.GA20339@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/events/uprobes.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 9db9cdf..fb961d5 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -117,7 +117,7 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
 	loff_t vaddr;
 
 	vaddr = vma->vm_start + offset;
-	vaddr -= vma->vm_pgoff << PAGE_SHIFT;
+	vaddr -= (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 
 	return vaddr;
 }
@@ -1450,7 +1450,7 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
 
 			inode = vma->vm_file->f_mapping->host;
 			offset = bp_vaddr - vma->vm_start;
-			offset += (vma->vm_pgoff << PAGE_SHIFT);
+			offset += (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 			uprobe = find_uprobe(inode, offset);
 		}
 
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