net: fix /proc/net/snmp as memory corruptor
icmpmsg_put() can happily corrupt kernel memory, using a static
table and forgetting to reset an array index in a loop.
Remove the static array since its not safe without proper locking.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 8f5a403..a631a1f 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -237,43 +237,45 @@
SNMP_MIB_SENTINEL
};
+static void icmpmsg_put_line(struct seq_file *seq, unsigned long *vals,
+ unsigned short *type, int count)
+{
+ int j;
+
+ if (count) {
+ seq_printf(seq, "\nIcmpMsg:");
+ for (j = 0; j < count; ++j)
+ seq_printf(seq, " %sType%u",
+ type[j] & 0x100 ? "Out" : "In",
+ type[j] & 0xff);
+ seq_printf(seq, "\nIcmpMsg:");
+ for (j = 0; j < count; ++j)
+ seq_printf(seq, " %lu", vals[j]);
+ }
+}
+
static void icmpmsg_put(struct seq_file *seq)
{
#define PERLINE 16
- int j, i, count;
- static int out[PERLINE];
+ int i, count;
+ unsigned short type[PERLINE];
+ unsigned long vals[PERLINE], val;
struct net *net = seq->private;
count = 0;
for (i = 0; i < ICMPMSG_MIB_MAX; i++) {
-
- if (snmp_fold_field((void **) net->mib.icmpmsg_statistics, i))
- out[count++] = i;
- if (count < PERLINE)
- continue;
-
- seq_printf(seq, "\nIcmpMsg:");
- for (j = 0; j < PERLINE; ++j)
- seq_printf(seq, " %sType%u", i & 0x100 ? "Out" : "In",
- i & 0xff);
- seq_printf(seq, "\nIcmpMsg: ");
- for (j = 0; j < PERLINE; ++j)
- seq_printf(seq, " %lu",
- snmp_fold_field((void **) net->mib.icmpmsg_statistics,
- out[j]));
- seq_putc(seq, '\n');
+ val = snmp_fold_field((void **) net->mib.icmpmsg_statistics, i);
+ if (val) {
+ type[count] = i;
+ vals[count++] = val;
+ }
+ if (count == PERLINE) {
+ icmpmsg_put_line(seq, vals, type, count);
+ count = 0;
+ }
}
- if (count) {
- seq_printf(seq, "\nIcmpMsg:");
- for (j = 0; j < count; ++j)
- seq_printf(seq, " %sType%u", out[j] & 0x100 ? "Out" :
- "In", out[j] & 0xff);
- seq_printf(seq, "\nIcmpMsg:");
- for (j = 0; j < count; ++j)
- seq_printf(seq, " %lu", snmp_fold_field((void **)
- net->mib.icmpmsg_statistics, out[j]));
- }
+ icmpmsg_put_line(seq, vals, type, count);
#undef PERLINE
}