From 8febdd85adaa41fa1fc1cb31286210fc2cd3ed0c Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Fri, 30 Dec 2005 17:18:53 -0800
Subject: [PATCH] sysctl: don't overflow the user-supplied buffer with '\0'
If the string was too long to fit in the user-supplied buffer,
the sysctl layer would zero-terminate it by writing past the
end of the buffer. Don't do that.
Noticed by Yi Yang <yang.y.yi@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
kernel/sysctl.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9990e10192e8e..ad0425a8f7099 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2201,14 +2201,12 @@ int sysctl_string(ctl_table *table, int __user *name, int nlen,
if (get_user(len, oldlenp))
return -EFAULT;
if (len) {
- l = strlen(table->data);
+ l = strlen(table->data)+1;
if (len > l) len = l;
if (len >= table->maxlen)
len = table->maxlen;
if(copy_to_user(oldval, table->data, len))
return -EFAULT;
- if(put_user(0, ((char __user *) oldval) + len))
- return -EFAULT;
if(put_user(len, oldlenp))
return -EFAULT;
}
--
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