From 5e1acb4afacc6229946c3d2b7ffc422b53fb2448 Mon Sep 17 00:00:00 2001 From: Alexey Kodanev Date: Fri, 2 Nov 2018 19:11:04 +0300 Subject: [PATCH] rtnetlink: restore handling of dumpit return value in rtnl_dump_all() For non-zero return from dumpit() we should break the loop in rtnl_dump_all() and return the result. Otherwise, e.g., we could get the memory leak in inet6_dump_fib() [1]. The pointer to the allocated struct fib6_walker there (saved in cb->args) can be lost, reset on the next iteration. Fix it by partially restoring the previous behavior before commit c63586dc9b3e ("net: rtnl_dump_all needs to propagate error from dumpit function"). The returned error from dumpit() is still passed further. [1]: unreferenced object 0xffff88001322a200 (size 96): comm "sshd", pid 1484, jiffies 4296032768 (age 1432.542s) hex dump (first 32 bytes): 00 01 00 00 00 00 ad de 00 02 00 00 00 00 ad de ................ 18 09 41 36 00 88 ff ff 18 09 41 36 00 88 ff ff ..A6......A6.... backtrace: [<0000000095846b39>] kmem_cache_alloc_trace+0x151/0x220 [<000000007d12709f>] inet6_dump_fib+0x68d/0x940 [<000000002775a316>] rtnl_dump_all+0x1d9/0x2d0 [<00000000d7cd302b>] netlink_dump+0x945/0x11a0 [<000000002f43485f>] __netlink_dump_start+0x55d/0x800 [<00000000f76bbeec>] rtnetlink_rcv_msg+0x4fa/0xa00 [<000000009b5761f3>] netlink_rcv_skb+0x29c/0x420 [<0000000087a1dae1>] rtnetlink_rcv+0x15/0x20 [<00000000691b703b>] netlink_unicast+0x4e3/0x6c0 [<00000000b5be0204>] netlink_sendmsg+0x7f2/0xba0 [<0000000096d2aa60>] sock_sendmsg+0xba/0xf0 [<000000008c1b786f>] __sys_sendto+0x1e4/0x330 [<0000000019587b3f>] __x64_sys_sendto+0xe1/0x1a0 [<00000000071f4d56>] do_syscall_64+0x9f/0x300 [<000000002737577f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<0000000057587684>] 0xffffffffffffffff Fixes: c63586dc9b3e ("net: rtnl_dump_all needs to propagate error from dumpit function") Signed-off-by: Alexey Kodanev Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e01274bd5e3e..33d9227a8b80 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3367,7 +3367,7 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) cb->seq = 0; } ret = dumpit(skb, cb); - if (ret < 0) + if (ret) break; } cb->family = idx; -- 2.30.2