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When reading pg_hba.conf and similar files, do not treat @file as an inclusion

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unless (1) the @ isn't quoted and (2) the filename isn't empty.  This guards
against unexpectedly treating usernames or other strings in "flat files"
as inclusion requests, as seen in a recent trouble report from Ed L.
The empty-filename case would be guaranteed to misbehave anyway, because our
subsequent path-munging behavior results in trying to read the directory
containing the current input file.

I think this might finally explain the report at
http://archives.postgresql.org/pgsql-bugs/2004-05/msg00132.php
of a crash after printing "authentication file token too long, skipping",
since I was able to duplicate that message (though not a crash) on a
platform where stdio doesn't refuse to read directories.  We never got
far in investigating that problem, but now I'm suspicious that the trigger
condition was an @ in the flat password file.

Back-patch to all active branches since the problem can be demonstrated in all
branches except HEAD.  The test case, creating a user named "@", doesn't cause
a problem in HEAD since we got rid of the flat password file.  Nonetheless it
seems like a good idea to not consider quoted @ as a file inclusion spec,
so I changed HEAD too.
This commit is contained in:
Tom Lane 2010-03-06 00:45:49 +00:00
parent 8eb81949a5
commit b8b34b7b44
1 changed files with 14 additions and 4 deletions
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18
src/backend/libpq/hba.c
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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/libpq/hba.c,v 1.200 2010/03/03 20:31:08 tgl Exp $
* $PostgreSQL: pgsql/src/backend/libpq/hba.c,v 1.201 2010/03/06 00:45:49 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -90,6 +90,10 @@ pg_isblank(const char c)
* double quotes (this allows the inclusion of blanks, but not newlines).
*
* The token, if any, is returned at *buf (a buffer of size bufsz).
* Also, we set *initial_quote to indicate whether there was quoting before
* the first character. (We use that to prevent "@x" from being treated
* as a file inclusion request. Note that @"x" should be so treated;
* we want to allow that to support embedded spaces in file paths.)
*
* If successful: store null-terminated token at *buf and return TRUE.
* If no more tokens on line: set *buf = '\0' and return FALSE.
@ -104,7 +108,7 @@ pg_isblank(const char c)
* token.
*/
static bool
next_token(FILE *fp, char *buf, int bufsz)
next_token(FILE *fp, char *buf, int bufsz, bool *initial_quote)
{
int c;
char *start_buf = buf;
@ -113,8 +117,11 @@ next_token(FILE *fp, char *buf, int bufsz)
bool was_quote = false;
bool saw_quote = false;
/* end_buf reserves two bytes to ensure we can append \n and \0 */
Assert(end_buf > start_buf);
*initial_quote = false;
/* Move over initial whitespace and commas */
while ((c = getc(fp)) != EOF && (pg_isblank(c) || c == ','))
;
@ -173,6 +180,8 @@ next_token(FILE *fp, char *buf, int bufsz)
{
in_quote = !in_quote;
saw_quote = true;
if (buf == start_buf)
*initial_quote = true;
}
c = getc(fp);
@ -216,12 +225,13 @@ next_token_expand(const char *filename, FILE *file)
char *comma_str = pstrdup("");
bool got_something = false;
bool trailing_comma;
bool initial_quote;
char *incbuf;
int needed;
do
{
if (!next_token(file, buf, sizeof(buf)))
if (!next_token(file, buf, sizeof(buf), &initial_quote))
break;
got_something = true;
@ -235,7 +245,7 @@ next_token_expand(const char *filename, FILE *file)
trailing_comma = false;
/* Is this referencing a file? */
if (buf[0] == '@')
if (!initial_quote && buf[0] == '@' && buf[1] != '\0')
incbuf = tokenize_inc_file(filename, buf + 1);
else
incbuf = pstrdup(buf);