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.

2 files changed, 14 insertions, 4 deletions

diff --git a/libbb/get_line_from_file.c b/libbb/get_line_from_file.c
index ce5c7810e..9f20f68cf 100644
--- a/libbb/get_line_from_file.c
+++ b/libbb/get_line_from_file.c
@@ -66,11 +66,16 @@ char* FAST_FUNC xmalloc_fgetline(FILE *file)
         size_t i;
         char *c = bb_get_chunk_from_file(file, &i);
 
+#if !ENABLE_PLATFORM_MINGW32
         if (i && c[--i] == '\n')
                 c[i] = '\0';
-#if ENABLE_PLATFORM_MINGW32
-        if (i && c[--i] == '\r')
+#else
+        if (i && c[--i] == '\n') {
                 c[i] = '\0';
+                if (i && c[--i] == '\r') {
+                        c[i] = '\0';
+                }
+        }
 #endif
 
         return c;
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;