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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Jia-Ju Bai <baijiaju1990@gmail.com>,
	Jiri Pirko <jiri@mellanox.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.4 10/21] net: sched: Fix a possible null-pointer dereference in dequeue_func()
Date: Fri,  9 Aug 2019 15:45:14 +0200	[thread overview]
Message-ID: <20190809134242.004869565@linuxfoundation.org> (raw)
In-Reply-To: <20190809134241.565496442@linuxfoundation.org>

From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit 051c7b39be4a91f6b7d8c4548444e4b850f1f56c ]

In dequeue_func(), there is an if statement on line 74 to check whether
skb is NULL:
    if (skb)

When skb is NULL, it is used on line 77:
    prefetch(&skb->end);

Thus, a possible null-pointer dereference may occur.

To fix this bug, skb->end is used when skb is not NULL.

This bug is found by a static analysis tool STCheck written by us.

Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM")
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sched/sch_codel.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -68,7 +68,8 @@ static struct sk_buff *dequeue(struct co
 {
 	struct sk_buff *skb = __skb_dequeue(&sch->q);
 
-	prefetch(&skb->end); /* we'll need skb_shinfo() */
+	if (skb)
+		prefetch(&skb->end); /* we'll need skb_shinfo() */
 	return skb;
 }
 



  parent reply	other threads:[~2019-08-09 13:45 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-09 13:45 [PATCH 4.4 00/21] 4.4.189-stable review Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 01/21] arm64: cpufeature: Fix CTR_EL0 field definitions Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 02/21] arm64: cpufeature: Fix feature comparison for CTR_EL0.{CWG,ERG} Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 03/21] netfilter: nfnetlink_acct: validate NFACCT_QUOTA parameter Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 04/21] HID: Add quirk for HP X1200 PIXART OEM mouse Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 05/21] tcp: be more careful in tcp_fragment() Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 06/21] atm: iphase: Fix Spectre v1 vulnerability Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 07/21] net: bridge: delete local fdb on device init failure Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 08/21] net: fix ifindex collision during namespace removal Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 09/21] tipc: compat: allow tipc commands without arguments Greg Kroah-Hartman
2019-08-09 13:45 ` Greg Kroah-Hartman [this message]
2019-08-09 13:45 ` [PATCH 4.4 11/21] net/mlx5: Use reversed order when unregister devices Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 12/21] bnx2x: Disable multi-cos feature Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 13/21] compat_ioctl: pppoe: fix PPPOEIOCSFWD handling Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 14/21] block: blk_init_allocated_queue() set q->fq as NULL in the fail case Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 15/21] spi: bcm2835: Fix 3-wire mode if DMA is enabled Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 16/21] x86: cpufeatures: Sort feature word 7 Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 17/21] x86/entry/64: Fix context tracking state warning when load_gs_index fails Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 18/21] x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 19/21] x86/speculation: Enable " Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 20/21] x86/entry/64: Use JMP instead of JMPQ Greg Kroah-Hartman
2019-08-09 13:45 ` [PATCH 4.4 21/21] x86/speculation/swapgs: Exclude ATOMs from speculation through SWAPGS Greg Kroah-Hartman
2019-08-09 22:08 ` [PATCH 4.4 00/21] 4.4.189-stable review shuah
2019-08-10  4:15 ` kernelci.org bot
2019-08-10 15:45 ` Guenter Roeck
2019-08-10 16:02 ` Dan Rue
2019-08-11  7:37   ` Greg Kroah-Hartman

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