fixdep: avoid underflow when end of entry doesn't coincide with EOF

Bug: https://bugs.gentoo.org/893776
Closes: https://bugs.busybox.net/show_bug.cgi?id=15326
Signed-off-by: Arsen Arsenović <arsen@gentoo.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 426b4888b..66be73aad 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -338,6 +338,11 @@ void parse_dep_file(void *map, size_t len)
                         do p--; while (!isalnum((unsigned char)*p));
                         p++;
                 }
+                if (p < m) {
+                        /* we've consumed the last filename of this list
+                           already.  */
+                        break;
+                }
                 memcpy(s, m, p-m); s[p-m] = 0;
                 if (strrcmp(s, "include/autoconf.h") &&
                     strrcmp(s, "arch/um/include/uml-config.h") &&