From: Anmol Karn <anmol.karan123@gmail.com>
To: ralf@linux-mips.org, davem@davemloft.net, kuba@kernel.org
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hams@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
syzkaller-bugs@googlegroups.com, anmol.karan123@gmail.com,
syzbot+a1c743815982d9496393@syzkaller.appspotmail.com
Subject: [Linux-kernel-mentees] [PATCH] net: rose: Fix Null pointer dereference in rose_send_frame()
Date: Thu, 15 Oct 2020 05:47:12 +0530 [thread overview]
Message-ID: <20201015001712.72976-1-anmol.karan123@gmail.com> (raw)
In rose_send_frame(), when comparing two ax.25 addresses, it assigns rose_call to
either global ROSE callsign or default port, but when the former block triggers and
rose_call is assigned by (ax25_address *)neigh->dev->dev_addr, a NULL pointer is
dereferenced by 'neigh' when dereferencing 'dev'.
- net/rose/rose_link.c
This bug seems to get triggered in this line:
rose_call = (ax25_address *)neigh->dev->dev_addr;
Prevent it by checking NULL condition for neigh->dev before comparing addressed for
rose_call initialization.
Reported-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=9d2a7ca8c7f2e4b682c97578dfa3f236258300b3
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
---
I am bit sceptical about the error return code, please suggest if anything else is
appropriate in place of '-ENODEV'.
net/rose/rose_link.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/rose/rose_link.c b/net/rose/rose_link.c
index f6102e6f5161..92ea6a31d575 100644
--- a/net/rose/rose_link.c
+++ b/net/rose/rose_link.c
@@ -97,6 +97,9 @@ static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
ax25_address *rose_call;
ax25_cb *ax25s;
+ if (!neigh->dev)
+ return -ENODEV;
+
if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
rose_call = (ax25_address *)neigh->dev->dev_addr;
else
--
2.28.0
WARNING: multiple messages have this Message-ID (diff)
From: Anmol Karn <anmol.karan123@gmail.com>
To: ralf@linux-mips.org, davem@davemloft.net, kuba@kernel.org
Cc: netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
linux-kernel@vger.kernel.org,
syzbot+a1c743815982d9496393@syzkaller.appspotmail.com,
linux-hams@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] net: rose: Fix Null pointer dereference in rose_send_frame()
Date: Thu, 15 Oct 2020 05:47:12 +0530 [thread overview]
Message-ID: <20201015001712.72976-1-anmol.karan123@gmail.com> (raw)
In rose_send_frame(), when comparing two ax.25 addresses, it assigns rose_call to
either global ROSE callsign or default port, but when the former block triggers and
rose_call is assigned by (ax25_address *)neigh->dev->dev_addr, a NULL pointer is
dereferenced by 'neigh' when dereferencing 'dev'.
- net/rose/rose_link.c
This bug seems to get triggered in this line:
rose_call = (ax25_address *)neigh->dev->dev_addr;
Prevent it by checking NULL condition for neigh->dev before comparing addressed for
rose_call initialization.
Reported-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=9d2a7ca8c7f2e4b682c97578dfa3f236258300b3
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
---
I am bit sceptical about the error return code, please suggest if anything else is
appropriate in place of '-ENODEV'.
net/rose/rose_link.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/rose/rose_link.c b/net/rose/rose_link.c
index f6102e6f5161..92ea6a31d575 100644
--- a/net/rose/rose_link.c
+++ b/net/rose/rose_link.c
@@ -97,6 +97,9 @@ static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
ax25_address *rose_call;
ax25_cb *ax25s;
+ if (!neigh->dev)
+ return -ENODEV;
+
if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
rose_call = (ax25_address *)neigh->dev->dev_addr;
else
--
2.28.0
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next reply other threads:[~2020-10-15 1:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 0:17 Anmol Karn [this message]
2020-10-15 0:17 ` [Linux-kernel-mentees] [PATCH] net: rose: Fix Null pointer dereference in rose_send_frame() Anmol Karn
2020-10-15 5:12 ` Greg KH
2020-10-15 5:12 ` Greg KH
2020-10-15 14:10 ` Anmol Karn
2020-10-15 14:10 ` Anmol Karn
2020-10-15 15:50 ` Greg KH
2020-10-15 15:50 ` Greg KH
2020-10-15 18:28 ` Anmol Karn
2020-10-15 18:28 ` Anmol Karn
2020-10-30 10:54 ` Anmol Karn
2020-10-30 10:54 ` Anmol Karn
2020-11-01 11:02 ` Greg KH
2020-11-01 11:02 ` Greg KH
2020-11-01 15:48 ` Anmol Karn
2020-11-01 15:48 ` Anmol Karn
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