From: Dan Carpenter <error27@gmail.com>
To: Dan Williams <dcbw@redhat.com>, javier@cozybit.com
Cc: "John W. Linville" <linville@tuxdriver.com>,
libertas-dev@lists.infradead.org, linux-wireless@vger.kernel.org,
netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [patch] libertas: fix write past end of array in mesh_id_get()
Date: Thu, 10 Mar 2011 18:23:26 +0300 [thread overview]
Message-ID: <20110310152326.GA2008@bicker> (raw)
defs.meshie.val.mesh_id is 32 chars long. It's not supposed to be NUL
terminated. This code puts a terminator on the end to make it easier to
print to sysfs. The problem is that if the mesh_id fills the entire
buffer the original code puts the terminator one spot past the end.
The way the original code was written, there was a check to make sure
that maxlen was less than PAGE_SIZE. Since we know that maxlen is at
most 34 chars, I just removed the check.
Signed-off-by: Dan Carpenter <error27@gmail.com>
diff --git a/drivers/net/wireless/libertas/mesh.c b/drivers/net/wireless/libertas/mesh.c
index acf3bf6..9d097b9 100644
--- a/drivers/net/wireless/libertas/mesh.c
+++ b/drivers/net/wireless/libertas/mesh.c
@@ -918,7 +918,6 @@ static ssize_t mesh_id_get(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct mrvl_mesh_defaults defs;
- int maxlen;
int ret;
ret = mesh_get_default_parameters(dev, &defs);
@@ -931,13 +930,11 @@ static ssize_t mesh_id_get(struct device *dev, struct device_attribute *attr,
defs.meshie.val.mesh_id_len = IEEE80211_MAX_SSID_LEN;
}
- /* SSID not null terminated: reserve room for \0 + \n */
- maxlen = defs.meshie.val.mesh_id_len + 2;
- maxlen = (PAGE_SIZE > maxlen) ? maxlen : PAGE_SIZE;
+ memcpy(buf, defs.meshie.val.mesh_id, defs.meshie.val.mesh_id_len);
+ buf[defs.meshie.val.mesh_id_len] = '\n';
+ buf[defs.meshie.val.mesh_id_len + 1] = '\0';
- defs.meshie.val.mesh_id[defs.meshie.val.mesh_id_len] = '\0';
-
- return snprintf(buf, maxlen, "%s\n", defs.meshie.val.mesh_id);
+ return defs.meshie.val.mesh_id_len + 1;
}
/**
next reply other threads:[~2011-03-10 15:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-10 15:23 Dan Carpenter [this message]
2011-03-10 17:02 ` [patch] libertas: fix write past end of array in mesh_id_get() Dan Williams
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