From cdda88912d62f9603d27433338a18be83ef23ac1 Mon Sep 17 00:00:00 2001 From: "bingtian.ly@taobao.com" Date: Wed, 23 Jan 2013 20:35:28 +0000 Subject: [PATCH] net: avoid to hang up on sending due to sysctl configuration overflow. I found if we write a larger than 4GB value to some sysctl variables, the sending syscall will hang up forever, because these variables are 32 bits, such large values make them overflow to 0 or negative. This patch try to fix overflow or prevent from zero value setup of below sysctl variables: net.core.wmem_default net.core.rmem_default net.core.rmem_max net.core.wmem_max net.ipv4.udp_rmem_min net.ipv4.udp_wmem_min net.ipv4.tcp_wmem net.ipv4.tcp_rmem Signed-off-by: Eric Dumazet Signed-off-by: Li Yu Signed-off-by: David S. Miller --- net/core/sysctl_net_core.c | 14 ++++++++++---- net/ipv4/sysctl_net_ipv4.c | 11 +++++++---- 2 files changed, 17 insertions(+), 8 deletions(-) diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index d1b08045a9df..cfdb46ab3a7f 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -20,6 +20,8 @@ #include #include +static int one = 1; + #ifdef CONFIG_RPS static int rps_sock_flow_sysctl(ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) @@ -92,28 +94,32 @@ static struct ctl_table net_core_table[] = { .data = &sysctl_wmem_max, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "rmem_max", .data = &sysctl_rmem_max, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "wmem_default", .data = &sysctl_wmem_default, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "rmem_default", .data = &sysctl_rmem_default, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "dev_weight", diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index a25e1d286b99..2622707602d1 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -27,6 +27,7 @@ #include static int zero; +static int one = 1; static int two = 2; static int tcp_retr1_max = 255; static int ip_local_port_range_min[] = { 1, 1 }; @@ -549,14 +550,16 @@ static struct ctl_table ipv4_table[] = { .data = &sysctl_tcp_wmem, .maxlen = sizeof(sysctl_tcp_wmem), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "tcp_rmem", .data = &sysctl_tcp_rmem, .maxlen = sizeof(sysctl_tcp_rmem), .mode = 0644, - .proc_handler = proc_dointvec + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, }, { .procname = "tcp_app_win", @@ -779,7 +782,7 @@ static struct ctl_table ipv4_table[] = { .maxlen = sizeof(sysctl_udp_rmem_min), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = &zero + .extra1 = &one }, { .procname = "udp_wmem_min", @@ -787,7 +790,7 @@ static struct ctl_table ipv4_table[] = { .maxlen = sizeof(sysctl_udp_wmem_min), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = &zero + .extra1 = &one }, { } }; -- 2.20.1