Messages in this thread Patch in this message | | | From | Kuniyuki Iwashima <> | Subject | [PATCH v1 net 15/16] icmp: Fix data-races around sysctl. | Date | Tue, 5 Jul 2022 22:21:29 -0700 |
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While reading sysctl variables, it can be changed concurrently. So, we need to add READ_ONCE(). Then we can set proc_dointvec_minmax_lockless() as the handler to mark it safe.
Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- net/ipv4/icmp.c | 5 +++-- net/ipv4/sysctl_net_ipv4.c | 4 ++-- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index efea0e796f06..0f9e61d29f73 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -253,11 +253,12 @@ bool icmp_global_allow(void) spin_lock(&icmp_global.lock); delta = min_t(u32, now - icmp_global.stamp, HZ); if (delta >= HZ / 50) { - incr = sysctl_icmp_msgs_per_sec * delta / HZ ; + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; if (incr) WRITE_ONCE(icmp_global.stamp, now); } - credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst); + credit = min_t(u32, icmp_global.credit + incr, + READ_ONCE(sysctl_icmp_msgs_burst)); if (credit) { /* We want to use a credit of one in average, but need to randomize * it for security reasons. diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 706795a3b369..3b1d18be0857 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -555,7 +555,7 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_icmp_msgs_per_sec, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_lockless, .extra1 = SYSCTL_ZERO, }, { @@ -563,7 +563,7 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_icmp_msgs_burst, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_lockless, .extra1 = SYSCTL_ZERO, }, { -- 2.30.2
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