kmodloader: fix out-of-bound access when parsing .modinfo

Fixes output of "modinfo nf_conntrack_ipv4"

    module:         /lib/modules/4.4.40/nf_conntrack_ipv4.ko
    license:        GPL
    alias:          ip_conntrack
    alias:          nf_conntrack-2
    depends:        nf_conntrack,nf_defrag_ipv4
    src:            %pI4 dst=%pI4

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

diff --git a/kmodloader.c b/kmodloader.c
index 065ac82..c780379 100644 (file)
--- a/kmodloader.c
+++ b/kmodloader.c
@@ -302,12 +302,14 @@ static struct module* get_module_info(const char *module, const char *name)
        }
 
        strings = map + offset;
        }
 
        strings = map + offset;

-       while (strings && (strings < map + offset + size)) {
+       while (true) {

                char *sep;
                int len;
 
                while (!strings[0])
                        strings++;
                char *sep;
                int len;
 
                while (!strings[0])
                        strings++;

+               if (strings >= map + offset + size)
+                       break;

                sep = strstr(strings, "=");
                if (!sep)
                        break;
                sep = strstr(strings, "=");
                if (!sep)
                        break;


@@ -410,12 +412,14 @@ static int print_modinfo(char *module)
 
        strings = map + offset;
        printf("module:\t\t%s\n", module);
 
        strings = map + offset;
        printf("module:\t\t%s\n", module);

-       while (strings && (strings < map + offset + size)) {
+       while (true) {

                char *dup = NULL;
                char *sep;
 
                while (!strings[0])
                        strings++;
                char *dup = NULL;
                char *sep;
 
                while (!strings[0])
                        strings++;

+               if (strings >= map + offset + size)
+                       break;

                sep = strstr(strings, "=");
                if (!sep)
                        break;
                sep = strstr(strings, "=");
                if (!sep)
                        break;