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From: Yafang Shao <laoar.shao@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: netdev@vger.kernel.org, shaoyafang@didiglobal.com,
	Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH bpf-next] bpf: use the proper optlen when doing strncpy in bpf_getsockopt()
Date: Sat, 19 Jan 2019 14:20:52 +0800	[thread overview]
Message-ID: <1547878852-22081-1-git-send-email-laoar.shao@gmail.com> (raw)

As the last character of optval will be set with 0, so just copying
(optlen - 1) characters is enough.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 net/core/filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 447dd1b..7a4de22 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4262,7 +4262,7 @@ static unsigned long bpf_xdp_copy(void *dst_buff, const void *src_buff,
 
 			if (!icsk->icsk_ca_ops || optlen <= 1)
 				goto err_clear;
-			strncpy(optval, icsk->icsk_ca_ops->name, optlen);
+			strncpy(optval, icsk->icsk_ca_ops->name, optlen - 1);
 			optval[optlen - 1] = 0;
 			break;
 		case TCP_SAVED_SYN:
-- 
1.8.3.1


             reply	other threads:[~2019-01-19  6:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-19  6:20 Yafang Shao [this message]
2019-01-22 18:04 ` [PATCH bpf-next] bpf: use the proper optlen when doing strncpy in bpf_getsockopt() Martin Lau
2019-01-22 18:39   ` Lawrence Brakmo
2019-01-23 13:53   ` Daniel Borkmann

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