From: Anmol Karn <anmol.karan123@gmail.com>
To: davem@davemloft.net, kuba@kernel.org
Cc: mkubecek@suse.cz, andrew@lunn.ch, f.fainelli@gmail.com,
syzbot+9d1389df89299fa368dc@syzkaller.appspotmail.com,
netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
dan.carpenter@oracle.com
Subject: [Linux-kernel-mentees] [PATCH net] ethtool: strset: Fix out of bound read in strset_parse_request()
Date: Sun, 11 Oct 2020 02:39:29 +0530 [thread overview]
Message-ID: <20201010210929.620244-1-anmol.karan123@gmail.com> (raw)
Flag ``ETHTOOL_A_STRSET_COUNTS_ONLY`` tells the kernel to only return the string
counts of the sets, but, when req_info->counts_only tries to read the
tb[ETHTOOL_A_STRSET_COUNTS_ONLY] it gets out of bound.
- net/ethtool/strset.c
The bug seems to trigger in this line:
req_info->counts_only = tb[ETHTOOL_A_STRSET_COUNTS_ONLY];
Fix it by NULL checking for req_info->counts_only while
reading from tb[ETHTOOL_A_STRSET_COUNTS_ONLY].
Reported-by: syzbot+9d1389df89299fa368dc@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=730deff8fe9954a5e317924d9acff98d9c64a770
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
---
When I tried to reduce the index of tb[] by 1, the crash reproducer was not working anymore,
hence it's probably reading from tb[ETHTOOL_A_STRSET_STRINGSETS], but this won't give the
strset 'count' and hence is not a plausible fix. But checking for the req_info->counts_only
seems legit.
If I have missed something please let me know, and I will work towards fixing it in next version.
net/ethtool/strset.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ethtool/strset.c b/net/ethtool/strset.c
index 82707b662fe4..20a7b36698f3 100644
--- a/net/ethtool/strset.c
+++ b/net/ethtool/strset.c
@@ -174,7 +174,8 @@ static int strset_parse_request(struct ethnl_req_info *req_base,
if (ret < 0)
return ret;
- req_info->counts_only = tb[ETHTOOL_A_STRSET_COUNTS_ONLY];
+ if (req_info->counts_only)
+ req_info->counts_only = tb[ETHTOOL_A_STRSET_COUNTS_ONLY];
nla_for_each_nested(attr, nest, rem) {
u32 id;
--
2.28.0
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next reply other threads:[~2020-10-10 21:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-10 21:09 Anmol Karn [this message]
2020-10-11 16:54 ` [Linux-kernel-mentees] [PATCH net] ethtool: strset: Fix out of bound read in strset_parse_request() Jakub Kicinski
2020-10-11 19:07 ` Anmol karn
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