net: Do not allow negative values for busy_read and busy_poll sysctl interfaces

This change basically codifies what I think was already the limitations on
the busy_poll and busy_read sysctl interfaces.  We weren't checking the
lower bounds and as such could input negative values. The behavior when
that was used was dependent on the architecture. In order to prevent any
issues with that I am just disabling support for values less than 0 since
this way we don't have to worry about any odd behaviors.

By limiting the sysctl values this way it also makes it consistent with how
we handle the SO_BUSY_POLL socket option since the value appears to be
reported as a signed integer value and negative values are rejected.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 4ead336e14ea0b8fc5fdcf8e679da54dfca0716b..7f9cc400eca08c01c9014476aa4daf0852505b20 100644 (file)
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -408,14 +408,16 @@ static struct ctl_table net_core_table[] = {
                .data           = &sysctl_net_busy_poll,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &zero,
        },
        {
                .procname       = "busy_read",
                .data           = &sysctl_net_busy_read,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &zero,
        },
 #endif
 #ifdef CONFIG_NET_SCHED