blurhash_transcoder: prevent out-of-bound reads with <8bpp images (#20388)
The Blurhash library used by Mastodon requires an input encoded as 24 bits raw RGB data. The conversion to raw RGB using Imagemagick did not previously specify the desired bit depth. In some situations, this leads Imagemagick to output in a pixel format using less bpp than expected. This then manifested as segfaults of the Sidekiq process due to out-of-bounds read, or potentially a (highly noisy) memory infoleak. Fixes #19235.gh/stable
parent
73fecc3358
commit
36bc90e8aa
|
@ -5,7 +5,7 @@ module Paperclip
|
||||||
def make
|
def make
|
||||||
return @file unless options[:style] == :small || options[:blurhash]
|
return @file unless options[:style] == :small || options[:blurhash]
|
||||||
|
|
||||||
pixels = convert(':source RGB:-', source: File.expand_path(@file.path)).unpack('C*')
|
pixels = convert(':source -depth 8 RGB:-', source: File.expand_path(@file.path)).unpack('C*')
|
||||||
geometry = options.fetch(:file_geometry_parser).from_file(@file)
|
geometry = options.fetch(:file_geometry_parser).from_file(@file)
|
||||||
|
|
||||||
attachment.instance.blurhash = Blurhash.encode(geometry.width, geometry.height, pixels, **(options[:blurhash] || {}))
|
attachment.instance.blurhash = Blurhash.encode(geometry.width, geometry.height, pixels, **(options[:blurhash] || {}))
|
||||||
|
|
Reference in New Issue