[PATCH 049/510] beceem: don't overrun user buffer on read

Greg Kroah-Hartman gregkh at suse.de
Mon Jan 10 20:36:13 UTC 2011


From: Stephen Hemminger <stephen.hemminger at vyatta.com>

Serious bug in original code, if app reads 10 bytes but 20 byte msg
received memory would get overwritten.

Signed-off-by: Stephen Hemminger <shemminger at vyatta.com>
---
 drivers/staging/bcm/Bcmchar.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index 1a25560..8089d19 100644
--- a/drivers/staging/bcm/Bcmchar.c
+++ b/drivers/staging/bcm/Bcmchar.c
@@ -139,7 +139,7 @@ static ssize_t bcm_char_read(struct file *filp, char __user *buf, size_t size, l
 	if(Packet)
 	{
 		PktLen = Packet->len;
-		if(copy_to_user(buf, Packet->data, PktLen))
+		if(copy_to_user(buf, Packet->data, min_t(size_t, PktLen, size)))
 		{
 			dev_kfree_skb(Packet);
 			BCM_DEBUG_PRINT(Adapter,DBG_TYPE_PRINTK, 0, 0, "\nReturning from copy to user failure \n");
-- 
1.7.3.2




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