Improve ispell dictionary's defenses against bad affix files.

Don't crash if an ispell dictionary definition contains flags but not
any compound affixes.  (This isn't a security issue since only superusers
can install affix files, but still it's a bad thing.)

Also, be more careful about detecting whether an affix-file FLAG command
is old-format (ispell) or new-format (myspell/hunspell).  And change the
error message about mixed old-format and new-format commands into something
intelligible.

Per bug #11770 from Emre Hasegeli.  Back-patch to all supported branches.

diff --git a/src/backend/tsearch/spell.c b/src/backend/tsearch/spell.c
index 530c6eddb8cacf09fc9a57ab9dea698201cf647f..b32dc471aa3a5e0c5f36ac9e551d7c4c1b8c269f 100644 (file)
--- a/src/backend/tsearch/spell.c
+++ b/src/backend/tsearch/spell.c
@@ -599,6 +599,9 @@ addFlagValue(IspellDict *Conf, char *s, uint32 val)
    Conf->usecompound = true;
 }
 
+/*
+ * Import an affix file that follows MySpell or Hunspell format
+ */
 static void
 NIImportOOAffixes(IspellDict *Conf, const char *filename)
 {
@@ -757,6 +760,10 @@ nextline:
  * import affixes
  *
  * Note caller must already have applied get_tsearch_config_filename
+ *
+ * This function is responsible for parsing ispell ("old format") affix files.
+ * If we realize that the file contains new-format commands, we pass off the
+ * work to NIImportOOAffixes(), which will re-read the whole file.
  */
 void
 NIImportAffixes(IspellDict *Conf, const char *filename)
@@ -833,13 +840,6 @@ NIImportAffixes(IspellDict *Conf, const char *filename)
 
            while (*s && t_isspace(s))
                s += pg_mblen(s);
-           oldformat = true;
-
-           /* allow only single-encoded flags */
-           if (pg_mblen(s) != 1)
-               ereport(ERROR,
-                       (errcode(ERRCODE_CONFIG_FILE_ERROR),
-                        errmsg("multibyte flag character is not allowed")));
 
            if (*s == '*')
            {
@@ -855,26 +855,30 @@ NIImportAffixes(IspellDict *Conf, const char *filename)
            if (*s == '\\')
                s++;
 
-           /* allow only single-encoded flags */
-           if (pg_mblen(s) != 1)
-               ereport(ERROR,
-                       (errcode(ERRCODE_CONFIG_FILE_ERROR),
-                        errmsg("multibyte flag character is not allowed")));
-
-           flag = *(unsigned char *) s;
-           goto nextline;
-       }
-       if (STRNCMP(recoded, "COMPOUNDFLAG") == 0 || STRNCMP(recoded, "COMPOUNDMIN") == 0 ||
-           STRNCMP(recoded, "PFX") == 0 || STRNCMP(recoded, "SFX") == 0)
-       {
-           if (oldformat)
-               ereport(ERROR,
-                       (errcode(ERRCODE_CONFIG_FILE_ERROR),
-                        errmsg("wrong affix file format for flag")));
-           tsearch_readline_end(&trst);
-           NIImportOOAffixes(Conf, filename);
-           return;
+           /*
+            * An old-format flag is a single ASCII character; we expect it to
+            * be followed by EOL, whitespace, or ':'.  Otherwise this is a
+            * new-format flag command.
+            */
+           if (*s && pg_mblen(s) == 1)
+           {
+               flag = *(unsigned char *) s;
+               s++;
+               if (*s == '\0' || *s == '#' || *s == '\n' || *s == ':' ||
+                   t_isspace(s))
+               {
+                   oldformat = true;
+                   goto nextline;
+               }
+           }
+           goto isnewformat;
        }
+       if (STRNCMP(recoded, "COMPOUNDFLAG") == 0 ||
+           STRNCMP(recoded, "COMPOUNDMIN") == 0 ||
+           STRNCMP(recoded, "PFX") == 0 ||
+           STRNCMP(recoded, "SFX") == 0)
+           goto isnewformat;
+
        if ((!suffixes) && (!prefixes))
            goto nextline;
 
@@ -888,6 +892,16 @@ nextline:
        pfree(pstr);
    }
    tsearch_readline_end(&trst);
+   return;
+
+isnewformat:
+   if (oldformat)
+       ereport(ERROR,
+               (errcode(ERRCODE_CONFIG_FILE_ERROR),
+       errmsg("affix file contains both old-style and new-style commands")));
+   tsearch_readline_end(&trst);
+
+   NIImportOOAffixes(Conf, filename);
 }
 
 static int
@@ -1501,6 +1515,10 @@ CheckCompoundAffixes(CMPDAffix **ptr, char *word, int len, bool CheckInPlace)
 {
    bool        issuffix;
 
+   /* in case CompoundAffix is null: */
+   if (*ptr == NULL)
+       return -1;
+
    if (CheckInPlace)
    {
        while ((*ptr)->affix)