From a50e4fd028a1ece2b1a04df2c9ae6581783e9eef Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 17 Mar 2021 16:10:37 -0400 Subject: [PATCH] Prevent buffer overrun in read_tablespace_map(). Robert Foggia of Trustwave reported that read_tablespace_map() fails to prevent an overrun of its on-stack input buffer. Since the tablespace map file is presumed trustworthy, this does not seem like an interesting security vulnerability, but still we should fix it just in the name of robustness. While here, document that pg_basebackup's --tablespace-mapping option doesn't work with tar-format output, because it doesn't. To make it work, we'd have to modify the tablespace_map file within the tarball sent by the server, which might be possible but I'm not volunteering. (Less-painful solutions would require changing the basebackup protocol so that the source server could adjust the map. That's not very appetizing either.) --- doc/src/sgml/ref/pg_basebackup.sgml | 8 +++++++- src/backend/access/transam/xlog.c | 2 +- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml index 14cc88a8522..8ce103301f2 100644 --- a/doc/src/sgml/ref/pg_basebackup.sgml +++ b/doc/src/sgml/ref/pg_basebackup.sgml @@ -161,6 +161,7 @@ PostgreSQL documentation tablespaces, the main data directory will be placed in the target directory, but all other tablespaces will be placed in the same absolute path as they have on the source server. + (See to change that.) This is the default format. @@ -241,7 +242,12 @@ PostgreSQL documentation the main data directory are updated to point to the new location. So the new data directory is ready to be used for a new server instance with all tablespaces in the updated locations. - + + + + Currently, this option only works with plain output format; it is + ignored if tar format is selected. + diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index f4d1ce5deae..9be0cb236d3 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -11959,7 +11959,7 @@ read_tablespace_map(List **tablespaces) } else if ((ch == '\n' || ch == '\r') && prev_ch == '\\') str[i - 1] = ch; - else + else if (i < sizeof(str) - 1) str[i++] = ch; prev_ch = ch; }