kbuild: replace unbounded sprintf call in modpost

kees · michal42 · commit 849464d1ba97 · 2013-11-06T22:30:03.000+01:00
The modpost tool could overflow its stack buffer if someone was running
with an insane shell environment. Regardless, it's technically a bug,
so this fixes it to truncate the string instead of seg-faulting.

Found by Coverity.

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
@@ -416,7 +416,7 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
 		basename = strrchr(modname, '/') + 1;
 	else
 		basename = modname;
-	sprintf(filelist, "%s/%.*s.mod", modverdir,
+	snprintf(filelist, sizeof(filelist), "%s/%.*s.mod", modverdir,
 		(int) strlen(basename) - 2, basename);
 
 	file = grab_file(filelist, &len);
