Report pg_hba line number and contents when users fail to log in

Instead of just reporting which user failed to log in, log both the
line number in the active pg_hba.conf file (which may not match reality
in case the file has been edited and not reloaded) and the contents of
the matching line (which will always be correct), to make it easier
to debug incorrect pg_hba.conf files.

The message to the client remains unchanged and does not include this
information, to prevent leaking security sensitive information.

Reviewed by Tom Lane and Dean Rasheed

Author: mhagander

src/backend/libpq/auth.c

@@ -297,9 +297,16 @@ auth_failed(Port *port, int status)
 			break;
 	}
 
-	ereport(FATAL,
-			(errcode(errcode_return),
-			 errmsg(errstr, port->user_name)));
+	if (port->hba)
+		ereport(FATAL,
+				(errcode(errcode_return),
+				 errmsg(errstr, port->user_name),
+				 errdetail_log("Connection matched pg_hba.conf line %d: \"%s\"", port->hba->linenumber, port->hba->rawline)));
+	else
+		ereport(FATAL,
+				(errcode(errcode_return),
+				 errmsg(errstr, port->user_name)));
+
 	/* doesn't return */
 }
 

src/backend/libpq/hba.c

@@ -50,6 +50,7 @@
 #define atoxid(x)  ((TransactionId) strtoul((x), NULL, 10))
 
 #define MAX_TOKEN	256
+#define MAX_LINE	8192
 
 /* callback data for check_network_callback */
 typedef struct check_network_data
@@ -93,7 +94,7 @@ static MemoryContext parsed_ident_context = NULL;
 
 
 static MemoryContext tokenize_file(const char *filename, FILE *file,
-			  List **lines, List **line_nums);
+			  List **lines, List **line_nums, List **raw_lines);
 static List *tokenize_inc_file(List *tokens, const char *outer_filename,
 				  const char *inc_filename);
 static bool parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline,
@@ -111,7 +112,8 @@ pg_isblank(const char c)
 
 
 /*
- * Grab one token out of fp. Tokens are strings of non-blank
+ * Grab one token out of the string pointed to by lineptr.
+ * Tokens are strings of non-blank
  * characters bounded by blank characters, commas, beginning of line, and
  * end of line. Blank means space or tab. Tokens can be delimited by
  * double quotes (this allows the inclusion of blanks, but not newlines).
@@ -134,7 +136,7 @@ pg_isblank(const char c)
  * Handle comments.
  */
 static bool
-next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote,
+next_token(char **lineptr, char *buf, int bufsz, bool *initial_quote,
 		   bool *terminating_comma)
 {
 	int			c;
@@ -151,10 +153,10 @@ next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote,
 	*terminating_comma = false;
 
 	/* Move over initial whitespace and commas */
-	while ((c = getc(fp)) != EOF && (pg_isblank(c) || c == ','))
+	while ((c = (*(*lineptr)++)) != '\0' && (pg_isblank(c) || c == ','))
 		;
 
-	if (c == EOF || c == '\n')
+	if (c == '\0' || c == '\n')
 	{
 		*buf = '\0';
 		return false;
@@ -164,17 +166,17 @@ next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote,
 	 * Build a token in buf of next characters up to EOF, EOL, unquoted comma,
 	 * or unquoted whitespace.
 	 */
-	while (c != EOF && c != '\n' &&
+	while (c != '\0' && c != '\n' &&
 		   (!pg_isblank(c) || in_quote))
 	{
 		/* skip comments to EOL */
 		if (c == '#' && !in_quote)
 		{
-			while ((c = getc(fp)) != EOF && c != '\n')
+			while ((c = (*(*lineptr)++)) != '\0' && c != '\n')
 				;
 			/* If only comment, consume EOL too; return EOL */
-			if (c != EOF && buf == start_buf)
-				c = getc(fp);
+			if (c != '\0' && buf == start_buf)
+				(*lineptr)++;
 			break;
 		}
 
@@ -186,7 +188,7 @@ next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote,
 			   errmsg("authentication file token too long, skipping: \"%s\"",
 					  start_buf)));
 			/* Discard remainder of line */
-			while ((c = getc(fp)) != EOF && c != '\n')
+			while ((c = (*(*lineptr)++)) != '\0' && c != '\n')
 				;
 			break;
 		}
@@ -215,15 +217,14 @@ next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote,
 				*initial_quote = true;
 		}
 
-		c = getc(fp);
+		c = *(*lineptr)++;
 	}
 
 	/*
 	 * Put back the char right after the token (critical in case it is EOL,
 	 * since we need to detect end-of-line at next call).
 	 */
-	if (c != EOF)
-		ungetc(c, fp);
+	(*lineptr)--;
 
 	*buf = '\0';
 
@@ -258,13 +259,13 @@ copy_hba_token(HbaToken *in)
 
 
 /*
- * Tokenize one HBA field from a file, handling file inclusion and comma lists.
+ * Tokenize one HBA field from a line, handling file inclusion and comma lists.
  *
  * The result is a List of HbaToken structs for each individual token,
  * or NIL if we reached EOL.
  */
 static List *
-next_field_expand(const char *filename, FILE *file)
+next_field_expand(const char *filename, char **lineptr)
 {
 	char		buf[MAX_TOKEN];
 	bool		trailing_comma;
@@ -273,7 +274,7 @@ next_field_expand(const char *filename, FILE *file)
 
 	do
 	{
-		if (!next_token(file, buf, sizeof(buf), &initial_quote, &trailing_comma))
+		if (!next_token(lineptr, buf, sizeof(buf), &initial_quote, &trailing_comma))
 			break;
 
 		/* Is this referencing a file? */
@@ -335,7 +336,7 @@ tokenize_inc_file(List *tokens,
 	}
 
 	/* There is possible recursion here if the file contains @ */
-	linecxt = tokenize_file(inc_fullname, inc_file, &inc_lines, &inc_line_nums);
+	linecxt = tokenize_file(inc_fullname, inc_file, &inc_lines, &inc_line_nums, NULL);
 
 	FreeFile(inc_file);
 	pfree(inc_fullname);
@@ -364,8 +365,8 @@ tokenize_inc_file(List *tokens,
 }
 
 /*
- * Tokenize the given file, storing the resulting data into two Lists: a
- * List of lines, and a List of line numbers.
+ * Tokenize the given file, storing the resulting data into three Lists: a
+ * List of lines, a List of line numbers, and a List of raw line contents.
  *
  * The list of lines is a triple-nested List structure.  Each line is a List of
  * fields, and each field is a List of HbaTokens.
@@ -377,7 +378,7 @@ tokenize_inc_file(List *tokens,
  */
 static MemoryContext
 tokenize_file(const char *filename, FILE *file,
-			  List **lines, List **line_nums)
+			  List **lines, List **line_nums, List **raw_lines)
 {
 	List	   *current_line = NIL;
 	List	   *current_field = NIL;
@@ -396,30 +397,51 @@ tokenize_file(const char *filename, FILE *file,
 
 	while (!feof(file) && !ferror(file))
 	{
-		current_field = next_field_expand(filename, file);
+		char rawline[MAX_LINE];
+		char *lineptr;
 
-		/* add tokens to list, unless we are at EOL or comment start */
-		if (list_length(current_field) > 0)
+		if (!fgets(rawline, sizeof(rawline), file))
+			break;
+		if (strlen(rawline) == MAX_LINE-1)
+			/* Line too long! */
+			ereport(ERROR,
+					(errcode(ERRCODE_CONFIG_FILE_ERROR),
+					 errmsg("authentication file line too long"),
+					 errcontext("line %d of configuration file \"%s\"",
+								line_number, filename)));
+
+		/* Strip trailing linebreak from rawline */
+		while (rawline[strlen(rawline)-1] == '\n' ||
+			   rawline[strlen(rawline)-1] == '\r')
+			rawline[strlen(rawline)-1] = '\0';
+
+		lineptr = rawline;
+		while (strlen(lineptr) > 0)
 		{
-			if (current_line == NIL)
-			{
-				/* make a new line List, record its line number */
-				current_line = lappend(current_line, current_field);
-				*lines = lappend(*lines, current_line);
-				*line_nums = lappend_int(*line_nums, line_number);
-			}
-			else
+			current_field = next_field_expand(filename, &lineptr);
+
+			/* add tokens to list, unless we are at EOL or comment start */
+			if (list_length(current_field) > 0)
 			{
-				/* append tokens to current line's list */
-				current_line = lappend(current_line, current_field);
+				if (current_line == NIL)
+				{
+					/* make a new line List, record its line number */
+					current_line = lappend(current_line, current_field);
+					*lines = lappend(*lines, current_line);
+					*line_nums = lappend_int(*line_nums, line_number);
+					if (raw_lines)
+						*raw_lines = lappend(*raw_lines, pstrdup(rawline));
+				}
+				else
+				{
+					/* append tokens to current line's list */
+					current_line = lappend(current_line, current_field);
+				}
 			}
 		}
-		else
-		{
-			/* we are at real or logical EOL, so force a new line List */
-			current_line = NIL;
-			line_number++;
-		}
+		/* we are at real or logical EOL, so force a new line List */
+		current_line = NIL;
+		line_number++;
 	}
 
 	MemoryContextSwitchTo(oldcxt);
@@ -815,7 +837,7 @@ check_same_host_or_net(SockAddr *raddr, IPCompareMethod method)
  * NULL.
  */
 static HbaLine *
-parse_hba_line(List *line, int line_num)
+parse_hba_line(List *line, int line_num, char *raw_line)
 {
 	char	   *str;
 	struct addrinfo *gai_result;
@@ -831,6 +853,7 @@ parse_hba_line(List *line, int line_num)
 
 	parsedline = palloc0(sizeof(HbaLine));
 	parsedline->linenumber = line_num;
+	parsedline->rawline = pstrdup(raw_line);
 
 	/* Check the record type. */
 	field = list_head(line);
@@ -1761,8 +1784,10 @@ load_hba(void)
 	FILE	   *file;
 	List	   *hba_lines = NIL;
 	List	   *hba_line_nums = NIL;
+	List	   *hba_raw_lines = NIL;
 	ListCell   *line,
-			   *line_num;
+			   *line_num,
+			   *raw_line;
 	List	   *new_parsed_lines = NIL;
 	bool		ok = true;
 	MemoryContext linecxt;
@@ -1779,7 +1804,7 @@ load_hba(void)
 		return false;
 	}
 
-	linecxt = tokenize_file(HbaFileName, file, &hba_lines, &hba_line_nums);
+	linecxt = tokenize_file(HbaFileName, file, &hba_lines, &hba_line_nums, &hba_raw_lines);
 	FreeFile(file);
 
 	/* Now parse all the lines */
@@ -1789,11 +1814,11 @@ load_hba(void)
 								   ALLOCSET_DEFAULT_MINSIZE,
 								   ALLOCSET_DEFAULT_MAXSIZE);
 	oldcxt = MemoryContextSwitchTo(hbacxt);
-	forboth(line, hba_lines, line_num, hba_line_nums)
+	forthree(line, hba_lines, line_num, hba_line_nums, raw_line, hba_raw_lines)
 	{
 		HbaLine    *newline;
 
-		if ((newline = parse_hba_line(lfirst(line), lfirst_int(line_num))) == NULL)
+		if ((newline = parse_hba_line(lfirst(line), lfirst_int(line_num), lfirst(raw_line))) == NULL)
 		{
 			/*
 			 * Parse error in the file, so indicate there's a problem.  NB: a
@@ -2153,7 +2178,7 @@ load_ident(void)
 		return false;
 	}
 
-	linecxt = tokenize_file(IdentFileName, file, &ident_lines, &ident_line_nums);
+	linecxt = tokenize_file(IdentFileName, file, &ident_lines, &ident_line_nums, NULL);
 	FreeFile(file);
 
 	/* Now parse all the lines */

src/include/libpq/hba.h

@@ -53,6 +53,7 @@ typedef enum ConnType
 typedef struct HbaLine
 {
 	int			linenumber;
+	char	   *rawline;
 	ConnType	conntype;
 	List	   *databases;
 	List	   *roles;