From 58d71477528fa847abeb0f22fc3f880e238fdb69 Mon Sep 17 00:00:00 2001 From: Philippe PITTOLI Date: Sun, 19 May 2024 18:09:19 +0200 Subject: [PATCH] Blah. --- graphs/graphs.ms | 28 ++++++++++++++++++++++------ src/dodb.cr | 2 -- 2 files changed, 22 insertions(+), 8 deletions(-) diff --git a/graphs/graphs.ms b/graphs/graphs.ms index a747f52..b025502 100644 --- a/graphs/graphs.ms +++ b/graphs/graphs.ms @@ -883,7 +883,7 @@ This is not acceptable for databases with large partitions and tags: memory will Right now, security isn't managed in DODB, at all. Sure, DODB isn't vulnerable to SQL injections, but an internet-facing application may encounter a few other problems including, but not limited to, code injection, buffer overflows, etc. Of course, DODB isn't a mechanism to protect applications from any possible attack, so most of the vulnerabilities cannot be countered by the library. -However, a few security mechanisms exist to prevent data leak or data modification from an outsider, and the DODB library should implement some of them in the future. +However, a few security mechanisms exist to prevent data leak or data modification from an outsider and the DODB library may implement some of them in the future. .B "Preventing data leak" . Since DODB is a library, any attack on the application using it can lead to a data leak. @@ -891,15 +891,31 @@ For the moment, any part of the application can access data stored in memory. Operating systems provide system calls to protect parts of the allocated memory. For instance, .FUNCTION_CALL mlock -prevents a region of memory from being put in the swap, which may lead to a data leak. -Also, +prevents a region of memory from being put in the swap because it could lead to a data leak. +The +.FUNCTION_CALL madvise +syscall can prevent parts of the application's memory to be put in a code-dump\*[*], which is a debug file created when an application crashes containing (part of) the process's memory when it crashed. +.FOOTNOTE1 +.FUNCTION_CALL madvice +has the interesting option +.I MADV_DONTDUMP +to prevent a data leak through a core-dump, but it is linux-specific. +.FOOTNOTE2 + +In a running process, .FUNCTION_CALL mprotect prevents the application itself to access part of its own memory; -the idea is to read (or write) memory only once you ask for it via a syscall, so you cannot access it from anywhere by mistake (or after an attack). -.TBD +the idea is to read (or write) memory only once you ask for it via a syscall. +Thus, you cannot access data from anywhere (by mistake or after an attack). -.B "Discussion on security, not related to DODB" . +These mechanisms could be used internally by DODB to prevent a data leak since memory is handled by the library. +However, the Crystal language doesn't provide a way to manage memory manually and this may be a problem for mlock and mprotect. +Depending on the plateform (the operating system), these syscalls may require the memory to be aligned with the memory pages. +Thus, the implementation won't be easy. + +.B "Side-note. Discussion on security" . No authorization mechanism prevents the application to access un-authorized data, including, but not limited to, any file on the file-system. +Since this implementation of DODB is related to the Crystal language (which isn't fully ported to the OpenBSD plateform at-the-moment), this is a problem. . . .SECTION Conclusion diff --git a/src/dodb.cr b/src/dodb.cr index 9b1161c..2a9d1fa 100644 --- a/src/dodb.cr +++ b/src/dodb.cr @@ -109,7 +109,6 @@ abstract class DODB::Storage(V) hash end - ## # name is the name that will be used on the file system. def new_index(name : String, &block : Proc(V, String) | Proc(V, String | DODB::NoIndex)) CachedIndex(V).new(self, @directory_name, name, block).tap do |indexer| @@ -135,7 +134,6 @@ abstract class DODB::Storage(V) index.not_nil!.as(DODB::Index).get key end - ## # name is the name that will be used on the file system. def new_partition(name : String, &block : Proc(V, String) | Proc(V, String | DODB::NoIndex)) CachedPartition(V).new(self, @directory_name, name, block).tap do |table|