kbuild: fix a buffer overflow in modpost

[~andy/linux] / scripts / mod / sumversion.c

diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index 5c0754526a26e7a3bc475f143b23b74c8e31a204..d9cc6901d68082ea74a2add806d72b01738679c4 100644 (file)
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -7,6 +7,7 @@
 #include <ctype.h>
 #include <errno.h>
 #include <string.h>
+#include <limits.h>
 #include "modpost.h"
 
 /*
@@ -381,8 +382,11 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
        struct md4_ctx md;
        char *sources, *end, *fname;
        const char *basename;
-       char filelist[strlen(getenv("MODVERDIR")) + strlen("/") +
-                     strlen(modname) - strlen(".o") + strlen(".mod") + 1 ];
+       char filelist[PATH_MAX + 1];
+       char *modverdir = getenv("MODVERDIR");
+
+       if (!modverdir)
+               modverdir = ".";
 
        /* Source files for module are in .tmp_versions/modname.mod,
           after the first line. */
@@ -390,14 +394,13 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
                basename = strrchr(modname, '/') + 1;
        else
                basename = modname;
-       sprintf(filelist, "%s/%.*s.mod", getenv("MODVERDIR"),
+       sprintf(filelist, "%s/%.*s.mod", modverdir,
                (int) strlen(basename) - 2, basename);
 
        file = grab_file(filelist, &len);
-       if (!file) {
-               warn("could not find versions for %s\n", filelist);
+       if (!file)
+               /* not a module or .mod file missing - ignore */
                return;
-       }
 
        sources = strchr(file, '\n');
        if (!sources) {