libbb: fix CRLF handling

Ensure a trailing CR is only removed if it precedes a LF.

The two cases at issue are intended to read complete lines and remove
the line terminator.  In the normal case a trailing LF will be present
so removing the CR unconditionally worked.  However, if the last line
of a file was missing its LF or if a NUL was detected (in the case of
xmalloc_fgetline()) the CR might have been removed without justification.

1 files changed, 7 insertions, 2 deletions

diff --git a/libbb/parse_config.c b/libbb/parse_config.c
index f7a2b81b9..800a2935e 100644
--- a/libbb/parse_config.c
+++ b/libbb/parse_config.c
@@ -113,11 +113,16 @@ static int get_line_with_continuation(parser_t *parser)
         line = parser->line;
         for (;;) {
                 parser->lineno++;
+#if ENABLE_PLATFORM_MINGW32
                 if (line[len - 1] == '\n')
                         len--;
-#if ENABLE_PLATFORM_MINGW32
-                if (line[len - 1] == '\r')
+#else
+                if (line[len - 1] == '\n') {
                         len--;
+                        if (len != 0 && line[len - 1] == '\r') {
+                                len--;
+                        }
+                }
 #endif
                 if (len == 0 || line[len - 1] != '\\')
                         break;