[RFC] fs/kcore: change copy_to_user to copy_in_user
From: yalin wang
Date: Thu Aug 20 2015 - 04:59:23 EST
the copy_to_user() here expect can fix the fault on both kernel and
user address, this is not true on other platforms except x86,
change to user copy_in_user() so that can detect the page fault,
work as expected.
Signed-off-by: yalin wang <yalin.wang2010@xxxxxxxxx>
---
fs/proc/kcore.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 92e6726..4f28deb 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -515,8 +515,12 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
} else {
if (kern_addr_valid(start)) {
unsigned long n;
-
- n = copy_to_user(buffer, (char *)start, tsz);
+ if ((start + tsz < tsz) ||
+ (start + tsz) > TASK_SIZE)
+ return -EFAULT;
+ set_fs(KERNEL_DS);
+ n = copy_in_user(buffer, (char *)start, tsz);
+ set_fs(USER_DS);
/*
* We cannot distinguish between fault on source
* and fault on destination. When this happens
--
1.9.1
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