Changeset 25566 in project

Timestamp:

11/24/11 17:59:45 (9 years ago)

Author:

Alaric Snell-Pym

Message:

ugarit: Fixed non-keyed-hash algorithm, and wrote lots of security stuff in the README.

Location:

release/4/ugarit/trunk

Files:

• README.txt (modified) (9 diffs)
• test/run.scm (modified) (2 diffs)
• ugarit-core.scm (modified) (3 diffs)

release/4/ugarit/trunk/README.txt

@@ -356 +356 @@
 of block, and the salt string, producing hashes that attackers who can
 snoop the archive cannot use to find known blocks (see the "Security
-model" section below for more details). Whichever hash function you
-use, you will need to install the required Chicken egg with one of the
-following commands:
+model" section below for more details).
+
+I would recommend that you create a salt string from a secure entropy
+source, such as:
+
+   dd if=/dev/random bs=1 count=64 | base64 -w 0
+
+Whichever hash function you use, you will need to install the required
+Chicken egg with one of the following commands:
 
     chicken-install -s tiger-hash  # for tiger
@@ -400 +406 @@
 
       (encryption aes ([16|24|32] "We three kings of Orient are, one in a taxi one in a car, one on a scooter honking his hooter and smoking a fat cigar. Oh, star of wonder, star of light; star with royal dynamite"))
+
+I would recommend that you generate a long passphrase from a secure
+entropy source, such as:
+
+   dd if=/dev/random bs=1 count=64 | base64 -w 0
 
 Finally, the extra-paranoid can request that Ugarit prompt for a
@@ -432 +443 @@
 
       (storage "ssh ugarit@spiderman 'backend-fs splitlog /mnt/ugarit-data /mnt/ugarit-metadata/metadata 900000000'")
-      (hash tiger "Giung0ahKahsh9ahphu5EiGhAhth4eeyDahs2aiWAlohr6raYeequ8uiUr3Oojoh")
-      (encryption aes (32 "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"))
+      (hash tiger "i3HO7JeLCSa6Wa55uqTRqp4jppUYbXoxme7YpcHPnuoA+11ez9iOIA6B6eBIhZ0MbdLvvFZZWnRgJAzY8K2JBQ")
+      (encryption aes (32 "FN9m34J4bbD3vhPqh6+4BjjXDSPYpuyskJX73T1t60PP0rPdC3AxlrjVn4YDyaFSbx5WRAn4JBr7SBn2PLyxJw"))
       (compression lzma)
       (file-cache "/var/ugarit/cache")
@@ -444 +455 @@
 Print a copy out and lock it in your fire safe! Ok, currently, you
 might be able to recreate it if you remember where you put the
-storage, but encryption keys are harder to remember.
+storage, but encryption keys and hash salts are harder to remember...
 
 ## Your first backup
@@ -964 +975 @@
 ## Core
 
+* Add the option to support full HMAC for salted hashing; make this
+  the recommended setting, with syntax `(hash tiger hmac "SALT")`, and
+  require `(hash tiger simple "SALT")` to explicitly request legacy
+  mode. Note this in the upgrade notes for existing users.
+
+* Add the option to append HMACed signatures to the post-encryption
+  blocks in the archive, to protect against people who tamper with
+  blocks in order to try and exploit vulnerabilities in the
+  decompression or decryption code (and to more quickly detect
+  tampering in the pipeline, to reduce the DoS effect of all that
+  wasted decryption and decompression, potentially including things
+  that decrypt to giant amounts of RAM).
+
+* When extracting, wrap each restore operation under
+  extract-directory! with exception handling that logs the error and
+  then continues with the next dirent in the directory.
+
+* Check sensibly-worded conditions are raised when we try and fetch
+  nonexistant or corrupted blocks from the archive in `archive-get`.
+
 * Make `fold-archive-node`'s listing of tags at the top level report
   the lock status of the tags.
@@ -1091 +1122 @@
   symbols `.` and `..` being usable as meta-characters to do nothing
   or to go up a level. Write a utility procedure to parse a string
-  into such a form.
+  into such a form. Make it recognise and follow symlinks.
+
+* When symlinks are traversed by the path resolver and by the explore
+  CLI, make `<tag>/current` be a symlink to the timestamp of the
+  current snapshot rather than a clone of it, for neatness.
 
 ## Front-end
@@ -1099 +1134 @@
   passed since last time), or verbose (report every file), or very
   verbose (report every file and block).
+
+* Make the explore CLI let you cd into symlinks
 
 * Add a command to force removing a tag lock.
@@ -1162 +1199 @@
   backend binary that takes a path to a log file and a backend command
   line to wrap.
+
+* Invoke the archive unit tests with every compression and encryption
+  option, and different hashing algorithms with and without keys
 
 # Acknowledgements
@@ -1255 +1295 @@
   'end'. BUGFIX: Fixed tag locking, which was broken all over the
   place. Concurrent snapshots to the same tag should now block for one
-  another, although why you'd want to *do* that is questionable.
+  another, although why you'd want to *do* that is
+  questionable. BUGFIX: Fixed generation of non-keyed hashes, which
+  was incorrectly appending the type to the hash without an outer
+  hash. This breaks backwards compatability, but nobody was using the
+  old algorithm, right? I'll introduce it as an option if required.
 
 * 1.0.1: Consistency check on read blocks by default. Removed warning

release/4/ugarit/trunk/test/run.scm

@@ -164 +164 @@
                (test-define-values "Close key-stream writer" (ks-hash ks-reused?) ((key-stream-writer-finish! ksw)))
                (test-assert "Key stream did not already exist" (not ks-reused?))
-               (test "Correct hash"  "3293ac630c13f0245f92bbb1766e16167a4e58492dde73f3test-ks" ks-hash)
+               (test "Correct hash"  "947020be151022522aec2a98293963156059a7553655fe5a" ks-hash)
                (test "Key stream reads back OK" '() (fold-key-stream a ks-hash 'test-ks cons '()))
 
@@ -256 +256 @@
                (test-define-values "Close sexpr-stream writer" (ss-hash ss-reused?) ((sexpr-stream-writer-finish! ssw)))
                (test-assert "Sexpr stream did not already exist" (not ss-reused?))
-               (test "Correct hash"  "3293ac630c13f0245f92bbb1766e16167a4e58492dde73f3t" ss-hash)
+               (test "Correct hash"  "ffe0058890b682d7b3da062284635df245d7e209d8a23dee" ss-hash)
                (test "Sexpr stream reads back OK" '() (fold-sexpr-stream a ss-hash 't 'ti cons '()))
 

release/4/ugarit/trunk/ugarit-core.scm

@@ -88 +88 @@
 (no-autoload lzma (compress lzma:compress) (decompress lzma:decompress))
 (no-autoload z3 z3:encode-buffer z3:decode-buffer)
-(autoload tiger-hash tiger192-digest tiger192-binary-digest)
 (no-autoload sha2 sha256-digest sha384-digest sha512-digest sha512-binary-digest)
 (no-autoload aes make-aes128-encryptor make-aes128-decryptor make-aes192-encryptor make-aes192-decryptor make-aes256-encryptor make-aes256-decryptor)
@@ -105 +104 @@
 (use posix)
 (use posix-extras)
+(use tiger-hash)
 (use crypto-tools)
 (use stty)
@@ -188 +188 @@
 
 (define (choose-hash-function config)
-  (let ((make-basic-hash (lambda (hash) (lambda (block type) (string-append (hash block) (symbol->string type)))))
+  (let ((make-basic-hash (lambda (hash) (lambda (block type) (hash (string-append (hash block) (symbol->string type))))))
         (make-keyed-hash (lambda (hash key) (lambda (block type) (hash (string-append key (hash block) (symbol->string type)))))))
     (match config