rtnl_link: enhance decoding of struct rtnl_link_stats{,64}

Enhance runtime detection of struct rtnl_link_stats.rx_nohandler
and struct rtnl_link_stats64.rx_nohandler.

* rtnl_link.c (decode_rtnl_link_stats): Do not accept structure length
greater than min_size but less than sizeof(struct rtnl_link_stats).
(decode_rtnl_link_stats64): Likewise, so not accept structure length
greater than min_size but less than sizeof(struct rtnl_link_stats64).

diff --git a/rtnl_link.c b/rtnl_link.c
index 9909684240526f5f11c985b0c5a73a7644da0c7a..73b94aef8d53bc9cfce622a717332ba5f9fd87cb 100644 (file)
--- a/rtnl_link.c
+++ b/rtnl_link.c
@@ -50,11 +50,15 @@ decode_rtnl_link_stats(struct tcb *const tcp,
        struct rtnl_link_stats st;
        const unsigned int min_size =
                offsetofend(struct rtnl_link_stats, tx_compressed);
-       const unsigned int size = len < sizeof(st) ? min_size : sizeof(st);
+       const unsigned int def_size = sizeof(st);
+       const unsigned int size =
+               (len >= def_size) ? def_size :
+                                   ((len == min_size) ? min_size : 0);
 
-       if (len < min_size)
+       if (!size)
                return false;
-       else if (!umoven_or_printaddr(tcp, addr, size, &st)) {
+
+       if (!umoven_or_printaddr(tcp, addr, size, &st)) {
                PRINT_FIELD_U("{", st, rx_packets);
                PRINT_FIELD_U(", ", st, tx_packets);
                PRINT_FIELD_U(", ", st, rx_bytes);
@@ -82,7 +86,7 @@ decode_rtnl_link_stats(struct tcb *const tcp,
                PRINT_FIELD_U(", ", st, rx_compressed);
                PRINT_FIELD_U(", ", st, tx_compressed);
 #ifdef HAVE_STRUCT_RTNL_LINK_STATS_RX_NOHANDLER
-               if (len >= sizeof(st))
+               if (len >= def_size)
                        PRINT_FIELD_U(", ", st, rx_nohandler);
 #endif
                tprints("}");
@@ -196,11 +200,15 @@ decode_rtnl_link_stats64(struct tcb *const tcp,
        struct rtnl_link_stats64 st;
        const unsigned int min_size =
                offsetofend(struct rtnl_link_stats64, tx_compressed);
-       const unsigned int size = len < sizeof(st) ? min_size : sizeof(st);
+       const unsigned int def_size = sizeof(st);
+       const unsigned int size =
+               (len >= def_size) ? def_size :
+                                   ((len == min_size) ? min_size : 0);
 
-       if (len < min_size)
+       if (!size)
                return false;
-       else if (!umoven_or_printaddr(tcp, addr, size, &st)) {
+
+       if (!umoven_or_printaddr(tcp, addr, size, &st)) {
                PRINT_FIELD_U("{", st, rx_packets);
                PRINT_FIELD_U(", ", st, tx_packets);
                PRINT_FIELD_U(", ", st, rx_bytes);
@@ -228,7 +236,7 @@ decode_rtnl_link_stats64(struct tcb *const tcp,
                PRINT_FIELD_U(", ", st, rx_compressed);
                PRINT_FIELD_U(", ", st, tx_compressed);
 #ifdef HAVE_STRUCT_RTNL_LINK_STATS64_RX_NOHANDLER
-               if (len >= sizeof(st))
+               if (len >= def_size)
                        PRINT_FIELD_U(", ", st, rx_nohandler);
 #endif
                tprints("}");