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[174.204.201.51]) by smtp.gmail.com with ESMTPSA id b4sm14942570pji.52.2021.07.06.09.31.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jul 2021 09:31:57 -0700 (PDT) From: John Fastabend To: ast@kernel.org, daniel@iogearbox.net, andriin@fb.com, xiyou.wangcong@gmail.com Cc: john.fastabend@gmail.com, bpf@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH bpf v3 1/2] bpf, sockmap: fix potential memory leak on unlikely error case Date: Tue, 6 Jul 2021 09:31:49 -0700 Message-Id: <20210706163150.112591-2-john.fastabend@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210706163150.112591-1-john.fastabend@gmail.com> References: <20210706163150.112591-1-john.fastabend@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If skb_linearize is needed and fails we could leak a msg on the error handling. To fix ensure we kfree the msg block before returning error. Found during code review. Fixes: 4363023d2668e ("bpf, sockmap: Avoid failures from skb_to_sgvec when skb has frag_list") Signed-off-by: John Fastabend --- net/core/skmsg.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 9b6160a191f8..1a9059e5b3b3 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -508,10 +508,8 @@ static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, if (skb_linearize(skb)) return -EAGAIN; num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); - if (unlikely(num_sge < 0)) { - kfree(msg); + if (unlikely(num_sge < 0)) return num_sge; - } copied = skb->len; msg->sg.start = 0; @@ -530,6 +528,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb) { struct sock *sk = psock->sk; struct sk_msg *msg; + int err; /* If we are receiving on the same sock skb->sk is already assigned, * skip memory accounting and owner transition seeing it already set @@ -548,7 +547,10 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb) * into user buffers. */ skb_set_owner_r(skb, sk); - return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); + err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); + if (err < 0) + kfree(msg); + return err; } /* Puts an skb on the ingress queue of the socket already assigned to the