Merge branch 'tor-github/pr/980'

Signed-off-by: David Goulet <dgoulet@torproject.org>

7 files changed, 188 insertions, 11 deletions

diff --git a/src/lib/encoding/confline.c b/src/lib/encoding/confline.c
index 8110f3dd9c..fdb575e03f 100644
--- a/src/lib/encoding/confline.c
+++ b/src/lib/encoding/confline.c
@@ -82,6 +82,19 @@ config_line_find(const config_line_t *lines,
   return NULL;
 }
 
+/** As config_line_find(), but perform a case-insensitive comparison. */
+const config_line_t *
+config_line_find_case(const config_line_t *lines,
+                      const char *key)
+{
+  const config_line_t *cl;
+  for (cl = lines; cl; cl = cl->next) {
+    if (!strcasecmp(cl->key, key))
+      return cl;
+  }
+  return NULL;
+}
+
 /** Auxiliary function that does all the work of config_get_lines.
  * <b>recursion_level</b> is the count of how many nested %includes we have.
  * <b>opened_lst</b> will have a list of opened files if provided.
diff --git a/src/lib/encoding/confline.h b/src/lib/encoding/confline.h
index 3d9ae8a662..56ea36bf61 100644
--- a/src/lib/encoding/confline.h
+++ b/src/lib/encoding/confline.h
@@ -48,6 +48,8 @@ config_line_t *config_lines_dup_and_filter(const config_line_t *inp,
                                            const char *key);
 const config_line_t *config_line_find(const config_line_t *lines,
                                       const char *key);
+const config_line_t *config_line_find_case(const config_line_t *lines,
+                                           const char *key);
 int config_lines_eq(config_line_t *a, config_line_t *b);
 int config_count_key(const config_line_t *a, const char *key);
 void config_free_lines_(config_line_t *front);
diff --git a/src/lib/encoding/include.am b/src/lib/encoding/include.am
index 83e9211b6f..8272e4e5fa 100644
--- a/src/lib/encoding/include.am
+++ b/src/lib/encoding/include.am
@@ -11,6 +11,7 @@ src_lib_libtor_encoding_a_SOURCES =			\
 	src/lib/encoding/keyval.c			\
 	src/lib/encoding/kvline.c			\
 	src/lib/encoding/pem.c				\
+	src/lib/encoding/qstring.c			\
 	src/lib/encoding/time_fmt.c
 
 src_lib_libtor_encoding_testing_a_SOURCES = \
@@ -25,4 +26,5 @@ noinst_HEADERS +=					\
 	src/lib/encoding/keyval.h			\
 	src/lib/encoding/kvline.h			\
 	src/lib/encoding/pem.h				\
+	src/lib/encoding/qstring.h			\
 	src/lib/encoding/time_fmt.h
diff --git a/src/lib/encoding/kvline.c b/src/lib/encoding/kvline.c
index 307adc3f12..d4a8f510ba 100644
--- a/src/lib/encoding/kvline.c
+++ b/src/lib/encoding/kvline.c
@@ -16,6 +16,7 @@
 #include "lib/encoding/confline.h"
 #include "lib/encoding/cstring.h"
 #include "lib/encoding/kvline.h"
+#include "lib/encoding/qstring.h"
 #include "lib/malloc/malloc.h"
 #include "lib/string/compat_ctype.h"
 #include "lib/string/printf.h"
@@ -54,6 +55,15 @@ line_has_no_key(const config_line_t *line)
 }
 
 /**
+ * Return true iff the value in <b>line</b> is not set.
+ **/
+static bool
+line_has_no_val(const config_line_t *line)
+{
+  return line->value == NULL || strlen(line->value) == 0;
+}
+
+/**
  * Return true iff the all the lines in <b>line</b> can be encoded
  * using <b>flags</b>.
  **/
@@ -98,14 +108,25 @@ kvline_can_encode_lines(const config_line_t *line, unsigned flags)
  * If KV_OMIT_KEYS is set in <b>flags</b>, then pairs with empty keys are
  * allowed, and are encoded as 'Value'.  Otherwise, such pairs are not
  * allowed.
+ *
+ * If KV_OMIT_VALS is set in <b>flags</b>, then an empty value is
+ * encoded as 'Key', not as 'Key=' or 'Key=""'.  Mutually exclusive with
+ * KV_OMIT_KEYS.
+ *
+ * KV_QUOTED_QSTRING is not supported.
  */
 char *
 kvline_encode(const config_line_t *line,
               unsigned flags)
 {
+  tor_assert(! (flags & KV_QUOTED_QSTRING));
+
   if (!kvline_can_encode_lines(line, flags))
     return NULL;
 
+  tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
+             (KV_OMIT_KEYS|KV_OMIT_VALS));
+
   smartlist_t *elements = smartlist_new();
 
   for (; line; line = line->next) {
@@ -126,7 +147,10 @@ kvline_encode(const config_line_t *line,
       }
     }
 
-    if (esc) {
+    if ((flags & KV_OMIT_VALS) && line_has_no_val(line)) {
+      eq = "";
+      v = "";
+    } else if (esc) {
       tmp = esc_for_log(line->value);
       v = tmp;
     } else {
@@ -151,17 +175,30 @@ kvline_encode(const config_line_t *line,
  * allocated list of pairs on success, or NULL on failure.
  *
  * If KV_QUOTED is set in <b>flags</b>, then (double-)quoted values are
- * allowed. Otherwise, such values are not allowed.
+ * allowed and handled as C strings. Otherwise, such values are not allowed.
  *
  * If KV_OMIT_KEYS is set in <b>flags</b>, then values without keys are
  * allowed.  Otherwise, such values are not allowed.
+ *
+ * If KV_OMIT_VALS is set in <b>flags</b>, then keys without values are
+ * allowed.  Otherwise, such keys are not allowed.  Mutually exclusive with
+ * KV_OMIT_KEYS.
+ *
+ * If KV_QUOTED_QSTRING is set in <b>flags</b>, then double-quoted values
+ * are allowed and handled as QuotedStrings per qstring.c.  Do not add
+ * new users of this flag.
  */
 config_line_t *
 kvline_parse(const char *line, unsigned flags)
 {
+  tor_assert((flags & (KV_OMIT_KEYS|KV_OMIT_VALS)) !=
+             (KV_OMIT_KEYS|KV_OMIT_VALS));
+
   const char *cp = line, *cplast = NULL;
-  bool omit_keys = (flags & KV_OMIT_KEYS) != 0;
-  bool quoted = (flags & KV_QUOTED) != 0;
+  const bool omit_keys = (flags & KV_OMIT_KEYS) != 0;
+  const bool omit_vals = (flags & KV_OMIT_VALS) != 0;
+  const bool quoted = (flags & (KV_QUOTED|KV_QUOTED_QSTRING)) != 0;
+  const bool c_quoted = (flags & (KV_QUOTED)) != 0;
 
   config_line_t *result = NULL;
   config_line_t **next_line = &result;
@@ -171,27 +208,33 @@ kvline_parse(const char *line, unsigned flags)
 
   while (*cp) {
     key = val = NULL;
+    /* skip all spaces */
     {
       size_t idx = strspn(cp, " \t\r\v\n");
       cp += idx;
     }
     if (BUG(cp == cplast)) {
-      /* If we didn't parse anything, this code is broken. */
+      /* If we didn't parse anything since the last loop, this code is
+       * broken. */
       goto err; // LCOV_EXCL_LINE
     }
     cplast = cp;
     if (! *cp)
       break; /* End of string; we're done. */
 
-    /* Possible formats are K=V, K="V", V, and "V", depending on flags. */
+    /* Possible formats are K=V, K="V", K, V, and "V", depending on flags. */
 
-    /* Find the key. */
+    /* Find where the key ends */
     if (*cp != '\"') {
       size_t idx = strcspn(cp, " \t\r\v\n=");
 
       if (cp[idx] == '=') {
         key = tor_memdup_nulterm(cp, idx);
         cp += idx + 1;
+      } else if (omit_vals) {
+        key = tor_memdup_nulterm(cp, idx);
+        cp += idx;
+        goto commit;
       } else {
         if (!omit_keys)
           goto err;
@@ -203,7 +246,11 @@ kvline_parse(const char *line, unsigned flags)
       if (!quoted)
         goto err;
       size_t len=0;
-      cp = unescape_string(cp, &val, &len);
+      if (c_quoted) {
+        cp = unescape_string(cp, &val, &len);
+      } else {
+        cp = decode_qstring(cp, strlen(cp), &val, &len);
+      }
       if (cp == NULL || len != strlen(val)) {
         // The string contains a NUL or is badly coded.
         goto err;
@@ -214,6 +261,7 @@ kvline_parse(const char *line, unsigned flags)
       cp += idx;
     }
 
+  commit:
     if (key && strlen(key) == 0) {
       /* We don't allow empty keys. */
       goto err;
@@ -221,13 +269,15 @@ kvline_parse(const char *line, unsigned flags)
 
     *next_line = tor_malloc_zero(sizeof(config_line_t));
     (*next_line)->key = key ? key : tor_strdup("");
-    (*next_line)->value = val;
+    (*next_line)->value = val ? val : tor_strdup("");
     next_line = &(*next_line)->next;
     key = val = NULL;
   }
 
-  if (!kvline_can_encode_lines(result, flags)) {
-    goto err;
+  if (! (flags & KV_QUOTED_QSTRING)) {
+    if (!kvline_can_encode_lines(result, flags)) {
+      goto err;
+    }
   }
   return result;
 
diff --git a/src/lib/encoding/kvline.h b/src/lib/encoding/kvline.h
index 4eed30a223..dea2ce1809 100644
--- a/src/lib/encoding/kvline.h
+++ b/src/lib/encoding/kvline.h
@@ -17,6 +17,8 @@ struct config_line_t;
 
 #define KV_QUOTED    (1u<<0)
 #define KV_OMIT_KEYS (1u<<1)
+#define KV_OMIT_VALS (1u<<2)
+#define KV_QUOTED_QSTRING (1u<<3)
 
 struct config_line_t *kvline_parse(const char *line, unsigned flags);
 char *kvline_encode(const struct config_line_t *line, unsigned flags);
diff --git a/src/lib/encoding/qstring.c b/src/lib/encoding/qstring.c
new file mode 100644
index 0000000000..a92d28c706
--- /dev/null
+++ b/src/lib/encoding/qstring.c
@@ -0,0 +1,90 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file qstring.c
+ * \brief Implement QuotedString parsing.
+ *
+ * Note that this is only used for controller authentication; do not
+ * create new users for this.  Instead, prefer the cstring.c functions.
+ **/
+
+#include "orconfig.h"
+#include "lib/encoding/qstring.h"
+#include "lib/malloc/malloc.h"
+#include "lib/log/util_bug.h"
+
+/** If the first <b>in_len_max</b> characters in <b>start</b> contain a
+ * QuotedString, return the length of that
+ * string (as encoded, including quotes).  Otherwise return -1. */
+static inline int
+get_qstring_length(const char *start, size_t in_len_max,
+                          int *chars_out)
+{
+  const char *cp, *end;
+  int chars = 0;
+
+  if (*start != '\"')
+    return -1;
+
+  cp = start+1;
+  end = start+in_len_max;
+
+  /* Calculate length. */
+  while (1) {
+    if (cp >= end) {
+      return -1; /* Too long. */
+    } else if (*cp == '\\') {
+      if (++cp == end)
+        return -1; /* Can't escape EOS. */
+      ++cp;
+      ++chars;
+    } else if (*cp == '\"') {
+      break;
+    } else {
+      ++cp;
+      ++chars;
+    }
+  }
+  if (chars_out)
+    *chars_out = chars;
+  return (int)(cp - start+1);
+}
+
+/** Given a pointer to a string starting at <b>start</b> containing
+ * <b>in_len_max</b> characters, decode a string beginning with one double
+ * quote, containing any number of non-quote characters or characters escaped
+ * with a backslash, and ending with a final double quote.  Place the resulting
+ * string (unquoted, unescaped) into a newly allocated string in *<b>out</b>;
+ * store its length in <b>out_len</b>.  On success, return a pointer to the
+ * character immediately following the escaped string.  On failure, return
+ * NULL. */
+const char *
+decode_qstring(const char *start, size_t in_len_max,
+               char **out, size_t *out_len)
+{
+  const char *cp, *end;
+  char *outp;
+  int len, n_chars = 0;
+
+  len = get_qstring_length(start, in_len_max, &n_chars);
+  if (len<0)
+    return NULL;
+
+  end = start+len-1; /* Index of last quote. */
+  tor_assert(*end == '\"');
+  outp = *out = tor_malloc(len+1);
+  *out_len = n_chars;
+
+  cp = start+1;
+  while (cp < end) {
+    if (*cp == '\\')
+      ++cp;
+    *outp++ = *cp++;
+  }
+  *outp = '\0';
+  tor_assert((outp - *out) == (int)*out_len);
+
+  return end+1;
+}
diff --git a/src/lib/encoding/qstring.h b/src/lib/encoding/qstring.h
new file mode 100644
index 0000000000..fe15b655f1
--- /dev/null
+++ b/src/lib/encoding/qstring.h
@@ -0,0 +1,18 @@
+/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file qstring.h
+ * \brief Header for qstring.c
+ */
+
+#ifndef TOR_ENCODING_QSTRING_H
+#define TOR_ENCODING_QSTRING_H
+
+#include <stddef.h>
+
+const char *decode_qstring(const char *start, size_t in_len_max,
+                           char **out, size_t *out_len);
+
+#endif