The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y git checkout FETCH_HEAD git cherry-pick -x 5310760af1d4fbea1452bfc77db5f9a680f7ae47 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023082116-unfilled-sprinkled-a76f@gregkh' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

5310760af1d4 ("ipvs: fix racy memcpy in proc_do_sync_threshold") 1b90af292e71 ("ipvs: Improve robustness to the ipvs sysctl")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5310760af1d4fbea1452bfc77db5f9a680f7ae47 Mon Sep 17 00:00:00 2001 From: Sishuai Gong sishuai.system@gmail.com Date: Thu, 10 Aug 2023 15:12:42 -0400 Subject: [PATCH] ipvs: fix racy memcpy in proc_do_sync_threshold

When two threads run proc_do_sync_threshold() in parallel, data races could happen between the two memcpy():

Thread-1 Thread-2 memcpy(val, valp, sizeof(val)); memcpy(valp, val, sizeof(val));

This race might mess up the (struct ctl_table *) table->data, so we add a mutex lock to serialize them.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/netdev/B6988E90-0A1E-4B85-BF26-2DAF6D482433@gmail.co... Signed-off-by: Sishuai Gong sishuai.system@gmail.com Acked-by: Simon Horman horms@kernel.org Acked-by: Julian Anastasov ja@ssi.bg Signed-off-by: Florian Westphal fw@strlen.de

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index 62606fb44d02..4bb0d90eca1c 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -1876,6 +1876,7 @@ static int proc_do_sync_threshold(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { + struct netns_ipvs *ipvs = table->extra2; int *valp = table->data; int val[2]; int rc; @@ -1885,6 +1886,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write, .mode = table->mode, };

+ mutex_lock(&ipvs->sync_mutex); memcpy(val, valp, sizeof(val)); rc = proc_dointvec(&tmp, write, buffer, lenp, ppos); if (write) { @@ -1894,6 +1896,7 @@ proc_do_sync_threshold(struct ctl_table *table, int write, else memcpy(valp, val, sizeof(val)); } + mutex_unlock(&ipvs->sync_mutex); return rc; }

@@ -4321,6 +4324,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs) ipvs->sysctl_sync_threshold[0] = DEFAULT_SYNC_THRESHOLD; ipvs->sysctl_sync_threshold[1] = DEFAULT_SYNC_PERIOD; tbl[idx].data = &ipvs->sysctl_sync_threshold; + tbl[idx].extra2 = ipvs; tbl[idx++].maxlen = sizeof(ipvs->sysctl_sync_threshold); ipvs->sysctl_sync_refresh_period = DEFAULT_SYNC_REFRESH_PERIOD; tbl[idx++].data = &ipvs->sysctl_sync_refresh_period;