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authorArjan van de Ven <arjan@linux.intel.com>2009-09-26 20:51:14 +0200
committerJohn W. Linville <linville@tuxdriver.com>2009-09-28 16:55:06 -0400
commit8503bd8c7dc6f82ec2de9d05e0a476e6ca5adc8b (patch)
tree42da5de2f0ee624e675d7b27f7e8c05301de0d2d
parent0ff716136ab73d2fc1edc0664e38169e7a76bb9a (diff)
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wext: Add bound checks for copy_from_user
The wireless extensions have a copy_from_user to a local stack array "essid", but both me and gcc have failed to find where the bounds for this copy are located in the code. This patch adds some basic sanity checks for the copy length to make sure that we don't overflow the stack buffer. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: linux-wireless@vger.kernel.org Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--net/wireless/wext.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/net/wireless/wext.c b/net/wireless/wext.c
index 5b4a0cee441..ac4ac26b53c 100644
--- a/net/wireless/wext.c
+++ b/net/wireless/wext.c
@@ -773,10 +773,13 @@ static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd,
essid_compat = 1;
else if (IW_IS_SET(cmd) && (iwp->length != 0)) {
char essid[IW_ESSID_MAX_SIZE + 1];
+ unsigned int len;
+ len = iwp->length * descr->token_size;
- err = copy_from_user(essid, iwp->pointer,
- iwp->length *
- descr->token_size);
+ if (len > IW_ESSID_MAX_SIZE)
+ return -EFAULT;
+
+ err = copy_from_user(essid, iwp->pointer, len);
if (err)
return -EFAULT;