net: avoid to hang up on sending due to sysctl configuration overflow.

commit cdda88912d62f9603d27433338a18be83ef23ac1 upstream.

    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 <eric.dumazet@gmail.com>
Signed-off-by: Li Yu <raise.sail@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
 - Adjust context
 - Delete now-unused 'zero' variable]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit 98eee187cdee2807bd80e6c02180c5c2abae6453)
[wt: backported to 2.6.32: set strategy to sysctl_intvec where relevant]
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index e6bf72ce2fa781d9dbb577425504a5f2a8435a2b..a6003283ea0b06e355b00ed627d62d25d7dbc5df 100644 (file)
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -17,6 +17,8 @@
 static int zero = 0;
 static int ushort_max = 65535;
 
+static int one = 1;
+
 static struct ctl_table net_core_table[] = {
 #ifdef CONFIG_NET
        {
@@ -25,7 +27,9 @@ 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,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_CORE_RMEM_MAX,
@@ -33,7 +37,9 @@ static struct ctl_table net_core_table[] = {
                .data           = &sysctl_rmem_max,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_CORE_WMEM_DEFAULT,
@@ -41,7 +47,9 @@ static struct ctl_table net_core_table[] = {
                .data           = &sysctl_wmem_default,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_CORE_RMEM_DEFAULT,
@@ -49,7 +57,9 @@ static struct ctl_table net_core_table[] = {
                .data           = &sysctl_rmem_default,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_CORE_DEV_WEIGHT,

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index d957371a80d0ad755d99a9182568d9886b017815..d1a8883297cf7d2108188a10aec9d55a5fe7727e 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -22,6 +22,7 @@
 #include <net/inet_frag.h>
 
 static int zero;
+static int one = 1;
 static int tcp_retr1_max = 255;
 static int tcp_syn_retries_min = 1;
 static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
@@ -521,7 +522,9 @@ 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,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_TCP_RMEM,
@@ -529,7 +532,9 @@ static struct ctl_table ipv4_table[] = {
                .data           = &sysctl_tcp_rmem,
                .maxlen         = sizeof(sysctl_tcp_rmem),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .strategy       = sysctl_intvec,
+               .extra1         = &one,
        },
        {
                .ctl_name       = NET_TCP_APP_WIN,
@@ -735,7 +740,7 @@ static struct ctl_table ipv4_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .strategy       = sysctl_intvec,
-               .extra1         = &zero
+               .extra1         = &one
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
@@ -745,7 +750,7 @@ static struct ctl_table ipv4_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .strategy       = sysctl_intvec,
-               .extra1         = &zero
+               .extra1         = &one
        },
        { .ctl_name = 0 }
 };