aef8948f38
This commit addresses some issues with c3826f83 that moved the hex decoding routine to src/common/: - The decoding function lacked overflow checks, so when used for security-related features it was an open door to out-of-bound writes if not carefully used that could remain undetected. Like the base64 routines already in src/common/ used by SCRAM, this routine is reworked to check for overflows by having the size of the destination buffer passed as argument, with overflows checked before doing any writes. - The encoding routine was missing. This is moved to src/common/ and it gains the same overflow checks as the decoding part. On failure, the hex routines of src/common/ issue an error as per the discussion done to make them usable by frontend tools, but not by shared libraries. Note that this is why ECPG is left out of this commit, and it still includes a duplicated logic doing hex encoding and decoding. While on it, this commit uses better variable names for the source and destination buffers in the existing escape and base64 routines in encode.c and it makes them more robust to overflow detection. The previous core code issued a FATAL after doing out-of-bound writes if going through the SQL functions, which would be enough to detect problems when working on changes that impacted this area of the code. Instead, an error is issued before doing an out-of-bound write. The hex routines were being directly called for bytea conversions and backup manifests without such sanity checks. The current calls happen to not have any problems, but careless uses of such APIs could easily lead to CVE-class bugs. Author: Bruce Momjian, Michael Paquier Reviewed-by: Sehrope Sarkuni Discussion: https://postgr.es/m/20201231003557.GB22199@momjian.us
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.