From b8b34b7b44ee7d932b2a1317232ff15fb72cf1a7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 6 Mar 2010 00:45:49 +0000 Subject: [PATCH] When reading pg_hba.conf and similar files, do not treat @file as an inclusion 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. --- src/backend/libpq/hba.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/src/backend/libpq/hba.c b/src/backend/libpq/hba.c index afc39f45bf..7718b0be49 100644 --- a/src/backend/libpq/hba.c +++ b/src/backend/libpq/hba.c @@ -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); -- 2.40.0