[PATCH][RESEND] Avoid possible NULL pointer deref in 3c359 driver
From: Jesper Juhl <hidden>
Date: 2007-08-04 18:34:12
Also in:
lkml
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
(Resending old patch originally submitted at 1/7-2007 02:19) In xl_freemem(), if dev_if is NULL, the line struct xl_private *xl_priv =(struct xl_private *)dev->priv; will cause a NULL pointer dereference. However, if we move that assignment below the 'if' statement that tests for a NULL 'dev', then that NULL deref can never happen. It never hurts to be safe :-) Signed-off-by: Jesper Juhl <redacted> ---
diff --git a/drivers/net/tokenring/3c359.c b/drivers/net/tokenring/3c359.c
index e22a3f5..671f4da 100644
--- a/drivers/net/tokenring/3c359.c
+++ b/drivers/net/tokenring/3c359.c@@ -1044,15 +1044,17 @@ static void xl_freemem(struct net_device *dev) static irqreturn_t xl_interrupt(int irq, void *dev_id) { struct net_device *dev = (struct net_device *)dev_id; - struct xl_private *xl_priv =(struct xl_private *)dev->priv; - u8 __iomem * xl_mmio = xl_priv->xl_mmio ; - u16 intstatus, macstatus ; + struct xl_private *xl_priv; + u8 __iomem * xl_mmio; + u16 intstatus, macstatus; if (!dev) { - printk(KERN_WARNING "Device structure dead, aaahhhh !\n") ; + printk(KERN_WARNING "3c359: Device structure dead, aaahhhh!\n"); return IRQ_NONE; } + xl_priv = (struct xl_private *)dev->priv; + xl_mmio = xl_priv->xl_mmio; intstatus = readw(xl_mmio + MMIO_INTSTATUS) ; if (!(intstatus & 1)) /* We didn't generate the interrupt */