[elpa] externals/emms 52dac8ccc4 41/42: Remove most length limits from Vorbis bindat specs

[ELPA Syncer]

branch: externals/emms
commit 52dac8ccc47e6040d33045e8df989a09270d3bdb
Author: Petteri Hintsanen <petterih@iki.fi>
Commit: Petteri Hintsanen <petterih@iki.fi>

    Remove most length limits from Vorbis bindat specs
    
    Many of the field length limits were arbitrarily chosen and even too
    strict in practice.  It is better to check against the length of input
    data, which forms trivially an upper bound for the length of any
    field.
    
    Do still keep maximum metadata peek sizes to limit reading of
    excessive amounts of data, but increase the limit to 16 MB.
---
 emms-info-native-flac.el   | 12 +++++++-----
 emms-info-native-ogg.el    | 12 ++++++------
 emms-info-native-opus.el   | 11 ++++++-----
 emms-info-native-vorbis.el | 39 +++++++--------------------------------
 4 files changed, 26 insertions(+), 48 deletions(-)

diff --git a/emms-info-native-flac.el b/emms-info-native-flac.el
index 132ee33bd9..2315bb7fbe 100644
--- a/emms-info-native-flac.el
+++ b/emms-info-native-flac.el
@@ -34,7 +34,9 @@
 (require 'emms-info-native-vorbis)
 (require 'bindat)
 
-(defconst emms-info-native-flac--max-peek-size (* 2048 1024)
+(defvar bindat-raw)
+
+(defconst emms-info-native-flac--max-peek-size (* 16 1024 1024)
   "Maximum buffer size for metadata decoding.
 Functions in `emms-info-native-flac' read certain amounts of data
 into a temporary buffer while decoding metadata.  This variable
@@ -82,22 +84,22 @@ exhaustion in case of garbled or malicious inputs.")
   (if (eval-when-compile (fboundp 'bindat-type))
       (bindat-type
         (vendor-length uintr 32)
-        (_ unit (when (> vendor-length 
emms-info-native-vorbis--max-vendor-length)
+        (_ unit (when (> vendor-length (length bindat-raw))
                   (error "FLAC vendor length %s is too long"
                          vendor-length)))
         (vendor-string str vendor-length)
         (user-comments-list-length uintr 32)
-        (_ unit (when (> user-comments-list-length 
emms-info-native-vorbis--max-comments)
+        (_ unit (when (> user-comments-list-length (length bindat-raw))
                   (error "FLAC user comment list length %s is too long"
                          user-comments-list-length)))
         (user-comments repeat user-comments-list-length
                        type 
emms-info-native-vorbis--comment-field-bindat-spec))
     '((vendor-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-vendor-length)
+      (eval (when (> last (length bindat-raw))
               (error "FLAC vendor length %s is too long" last)))
       (vendor-string str (vendor-length))
       (user-comments-list-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-comments)
+      (eval (when (> last (length bindat-raw))
               (error "FLAC user comment list length %s is too long"
                      last)))
       (user-comments repeat
diff --git a/emms-info-native-ogg.el b/emms-info-native-ogg.el
index 457dc696f7..89c309e85f 100644
--- a/emms-info-native-ogg.el
+++ b/emms-info-native-ogg.el
@@ -47,13 +47,13 @@
 (defconst emms-info-native-ogg--page-size 65307
   "Maximum size for a single Ogg container page.")
 
-(defconst emms-info-native-ogg--max-peek-size (* 2048 1024)
+(defconst emms-info-native-ogg--max-peek-size (* 16 1024 1024)
   "Maximum buffer size for metadata decoding.
-Functions in `emms-info-native-ogg' read certain amounts of data into a
-temporary buffer while decoding metadata.  This variable controls
-the maximum size of that buffer: if more than
-`emms-info-native-ogg--max-peek-size' bytes are needed, an error is
-signaled.
+Functions in `emms-info-native-ogg' read certain amounts of data
+into a temporary buffer while decoding metadata.  This variable
+controls the maximum size of that buffer: if more than
+`emms-info-native-ogg--max-peek-size' bytes are needed, an error
+is signaled.
 
 Technically metadata blocks can have almost arbitrary lengths,
 but in practice processing must be constrained to prevent memory
diff --git a/emms-info-native-opus.el b/emms-info-native-opus.el
index efec5e9033..15f0aa487f 100644
--- a/emms-info-native-opus.el
+++ b/emms-info-native-opus.el
@@ -31,6 +31,8 @@
 (require 'emms-info-native-vorbis)
 (require 'bindat)
 
+(defvar bindat-raw)
+
 (defvar emms-info-native-opus--channel-count 0
   "Last decoded Opus channel count.")
 
@@ -101,13 +103,12 @@
                          emms-info-native-opus--tags-magic-pattern
                          opus-tags)))
         (vendor-length uintr 32)
-        (_ unit (when (> vendor-length 
emms-info-native-vorbis--max-vendor-length)
+        (_ unit (when (> vendor-length (length bindat-raw))
                   (error "Opus vendor length %s is too long"
                          vendor-length)))
         (vendor-string str vendor-length)
         (user-comments-list-length uintr 32)
-        (_ unit (when (> user-comments-list-length
-                         emms-info-native-vorbis--max-comments)
+        (_ unit (when (> user-comments-list-length (length bindat-raw))
                   (error "Opus user comment list length %s is too long"
                          user-comments-list-length)))
         (user-comments repeat user-comments-list-length
@@ -118,11 +119,11 @@
                      emms-info-native-opus--tags-magic-pattern
                      last)))
       (vendor-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-vendor-length)
+      (eval (when (> last (length bindat-raw))
               (error "Opus vendor length %s is too long" last)))
       (vendor-string str (vendor-length))
       (user-comments-list-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-comments)
+      (eval (when (> last (length bindat-raw))
               (error "Opus user comment list length %s is too long"
                      last)))
       (user-comments repeat
diff --git a/emms-info-native-vorbis.el b/emms-info-native-vorbis.el
index 77a49a7f32..7a8ccc6239 100644
--- a/emms-info-native-vorbis.el
+++ b/emms-info-native-vorbis.el
@@ -29,32 +29,7 @@
 
 (require 'bindat)
 
-(defconst emms-info-native-vorbis--max-comments 1024
-  "Maximum number of Vorbis comment fields in a stream.
-Technically a single Vorbis stream may have up to 2^32 comments,
-but in practice processing must be constrained to prevent memory
-exhaustion in case of garbled or malicious inputs.
-
-This limit is used with Opus and FLAC streams as well, since
-their comments have almost the same format as Vorbis.")
-
-(defconst emms-info-native-vorbis--max-comment-size (* 64 1024)
-  "Maximum length for a single Vorbis comment field.
-Technically a single Vorbis comment may have a length up to 2^32
-bytes, but in practice processing must be constrained to prevent
-memory exhaustion in case of garbled or malicious inputs.
-
-This limit is used with Opus and FLAC streams as well, since
-their comments have almost the same format as Vorbis.")
-
-(defconst emms-info-native-vorbis--max-vendor-length 1024
-  "Maximum length of Vorbis vendor string.
-Technically a vendor string can be up to 2^32 bytes long, but in
-practice processing must be constrained to prevent memory
-exhaustion in case of garbled or malicious inputs.
-
-This limit is used with Opus and FLAC streams as well, since
-their comments have almost the same format as Vorbis.")
+(defvar bindat-raw)
 
 (defconst emms-info-native-vorbis--accepted-fields
   '("album"
@@ -136,12 +111,12 @@ their comments have almost the same format as Vorbis.")
   (if (eval-when-compile (fboundp 'bindat-type))
       (bindat-type
         (length uintr 32)
-        (_ unit (when (> length emms-info-native-vorbis--max-comment-size)
+        (_ unit (when (> length (length bindat-raw))
                   (error "Vorbis comment length %s is too long"
                          length)))
         (user-comment str length))
     '((length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-comment-size)
+      (eval (when (> last (length bindat-raw))
               (error "Vorbis comment length %s is too long" last)))
       (user-comment str (length))))
   "Vorbis comment field specification.")
@@ -159,12 +134,12 @@ their comments have almost the same format as Vorbis.")
                          emms-info-native-vorbis--header-magic-pattern
                          vorbis)))
         (vendor-length uintr 32)
-        (_ unit (when (> vendor-length 
emms-info-native-vorbis--max-vendor-length)
+        (_ unit (when (> vendor-length (length bindat-raw))
                   (error "Vorbis vendor length %s is too long"
                          vendor-length)))
         (vendor-string str vendor-length)
         (user-comments-list-length uintr 32)
-        (_ unit (when (> user-comments-list-length 
emms-info-native-vorbis--max-comments)
+        (_ unit (when (> user-comments-list-length (length bindat-raw))
                   (error "Vorbis user comment list length %s is too long"
                          user-comments-list-length)))
         (user-comments repeat user-comments-list-length
@@ -183,11 +158,11 @@ their comments have almost the same format as Vorbis.")
                      emms-info-native-vorbis--header-magic-pattern
                      last)))
       (vendor-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-vendor-length)
+      (eval (when (> last (length bindat-raw))
               (error "Vorbis vendor length %s is too long" last)))
       (vendor-string str (vendor-length))
       (user-comments-list-length u32r)
-      (eval (when (> last emms-info-native-vorbis--max-comments)
+      (eval (when (> last (length bindat-raw))
               (error "Vorbis user comment list length %s is too long"
                      last)))
       (user-comments repeat