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AJvYcCXP6+lEhtaXwYf7tXAIKeCnrrA3WYR5R5xmrE5frPON6Co840ccna8Q5b4pLn3gZrkVose/5cpQ@vger.kernel.org, AJvYcCXyY9Z3RreDEiWltbaLWDL5VptN5eU+eJzGqIDOAprkqcmoTz4Ud4dxepBjbVMFdizZ/AA42hAG8nPqTQM=@vger.kernel.org X-Gm-Message-State: AOJu0YyySii6fZy6h1lT6VZd8kUp1gamLva3JzedIWSlZGOYOV3ZDEWL T4n/COuEVg65NUMfF5sBEJnDL4VSFGYGwCDQ27RadOVJUiGiOLFtTIW5KpOknoJXhA== X-Google-Smtp-Source: AGHT+IGUG5+Krz1IQiWBieU+4Vxekv7aSBW37q6c5L/WGRgJNouLTqurr4I/yDtJ7D2EojJr2/z9ow== X-Received: by 2002:a05:6a00:2d18:b0:720:aa27:2e45 with SMTP id d2e1a72fcca58-720b9c2907dmr14899650b3a.14.1730578108404; Sat, 02 Nov 2024 13:08:28 -0700 (PDT) Received: from localhost.localdomain ([240c:c701:2:805:409b:a7ac:813b:68b1]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-720c6a39a53sm3927105b3a.178.2024.11.02.13.08.24 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sat, 02 Nov 2024 13:08:27 -0700 (PDT) From: Yi Zou <03zouyi09.25@gmail.com> To: davem@davemloft.net Cc: 21210240012@m.fudan.edu.cn, 21302010073@m.fudan.edu.cn, dsahern@kernel.org, edumazet@google.com, pabeni@redhat.com, Markus.Elfring@web.de, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Yi Zou <03zouyi09.25@gmail.com> Subject: [PATCH] ipv6: ip6_fib: fix null-pointer dereference in ipv6_route_native_seq_show() Date: Sun, 3 Nov 2024 04:08:20 +0800 Message-ID: <20241102200820.1423-1-03zouyi09.25@gmail.com> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Check if fib6_nh is non-NULL before accessing fib6_nh->fib_nh_gw_family in ipv6_route_native_seq_show() to prevent a null-pointer dereference. Assign dev as dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL to ensure safe handling when nexthop_fib6_nh(rt->nh) returns NULL. Fixes: 0379e8e6a9ef ("ipv6: ip6_fib: avoid NPD in ipv6_route_native_seq_show()") Signed-off-by: Yi Zou <03zouyi09.25@gmail.com> --- net/ipv6/ip6_fib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index eb111d20615c..6632ab65d206 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -2555,14 +2555,14 @@ static int ipv6_route_native_seq_show(struct seq_file *seq, void *v) #else seq_puts(seq, "00000000000000000000000000000000 00 "); #endif - if (fib6_nh->fib_nh_gw_family) { + if (fib6_nh && fib6_nh->fib_nh_gw_family) { flags |= RTF_GATEWAY; seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6); } else { seq_puts(seq, "00000000000000000000000000000000"); } - dev = fib6_nh->fib_nh_dev; + dev = fib6_nh ? fib6_nh->fib_nh_dev : NULL; seq_printf(seq, " %08x %08x %08x %08x %8s\n", rt->fib6_metric, refcount_read(&rt->fib6_ref), 0, flags, dev ? dev->name : "");