better error handling, found by coverity.

diff --git a/src/readelf.c b/src/readelf.c
index 5dfcea544889f130c50ae55c93f64c4f6423e725..2c4cddb6aa907c33918cecc8261de82b872abeff 100644 (file)
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -27,7 +27,7 @@
 #include "file.h"
 
 #ifndef lint
-FILE_RCSID("@(#)$File: readelf.c,v 1.147 2018/08/01 09:56:24 christos Exp $")
+FILE_RCSID("@(#)$File: readelf.c,v 1.148 2018/08/01 10:02:20 christos Exp $")
 #endif
 
 #ifdef BUILTIN_ELF
@@ -921,7 +921,8 @@ get_string_on_virtaddr(struct magic_set *ms,
 
        offset = get_offset_from_virtaddr(ms, swap, clazz, fd, ph_off, ph_num,
            fsize, virtaddr);
-       if ((buflen = pread(fd, buf, CAST(size_t, buflen), offset)) <= 0) {
+       if (offset < 0 ||
+           (buflen = pread(fd, buf, CAST(size_t, buflen), offset)) <= 0) {
                file_badread(ms);
                return 0;
        }