From 76eda67dbc3f48c9dd6815a5aaf6014ea4a16771 Mon Sep 17 00:00:00 2001 From: Robert Ancell Date: Wed, 2 Feb 2022 12:36:08 +1300 Subject: [PATCH 1/4] Fix test GIF that was broken in the LZW code size, not the values of the pixels --- .../test-images/gif-test-suite/invalid-colors.gif | Bin 37 -> 35 bytes 1 file changed, 0 insertions(+), 0 deletions(-) diff --git a/tests/test-images/gif-test-suite/invalid-colors.gif b/tests/test-images/gif-test-suite/invalid-colors.gif index c3111525ac2d977a0dbedf917f2beae610b614f8..6c3a7240e6ba58c344051351eb3581887fa314c7 100644 GIT binary patch delta 11 ScmY#Yo*>J{%%s7|U=08YGy!b@ delta 13 UcmY#ZogmA>!}4E&fr-Hy01|-$Y5)KL -- GitLab From 0cf97225c9c227d11fc4ddf9cba8e8480672ee1b Mon Sep 17 00:00:00 2001 From: Robert Ancell Date: Wed, 2 Feb 2022 12:38:45 +1300 Subject: [PATCH 2/4] Add an assertion that checks for maximum LZW code size --- gdk-pixbuf/lzw.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/gdk-pixbuf/lzw.c b/gdk-pixbuf/lzw.c index 105daf2b1..15293560b 100644 --- a/gdk-pixbuf/lzw.c +++ b/gdk-pixbuf/lzw.c @@ -121,6 +121,8 @@ lzw_decoder_new (guint8 code_size) LZWDecoder *self; int i; + g_return_val_if_fail (code_size <= LZW_CODE_MAX, NULL); + self = g_object_new (lzw_decoder_get_type (), NULL); self->min_code_size = code_size; -- GitLab From 19ebba03117aefc9d0312f675f3a210ffdcc4907 Mon Sep 17 00:00:00 2001 From: Robert Ancell Date: Wed, 2 Feb 2022 14:03:13 +1300 Subject: [PATCH 3/4] Fix the check for maximum value of LZW initial code size. This value is the number of bits for each symbol (i.e. colour index) decoded via LZW. The maximum LZW code is specified as 12 bits, so the value here can only be 11 as two additional code words are required (clear and end of information) that immediately uses an additional bit. This implementation has always been wrong, and the Firefox implementation has the same issue so it seems a common misinterpretation of the spec. This has been changed here to avoid an assertion later in the LZW decoder. Note that there is never any reason for a GIF to be encoded with more than 8 bits of colour information, as the colour tables only support up to 8 bits. --- gdk-pixbuf/io-gif.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/gdk-pixbuf/io-gif.c b/gdk-pixbuf/io-gif.c index 1befba155..310bdff6a 100644 --- a/gdk-pixbuf/io-gif.c +++ b/gdk-pixbuf/io-gif.c @@ -499,8 +499,8 @@ gif_prepare_lzw (GifContext *context) /*g_message (_("GIF: EOF / read error on image data\n"));*/ return -1; } - - if (context->lzw_set_code_size > 12) { + + if (context->lzw_set_code_size >= 12) { g_set_error_literal (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, -- GitLab From 449441210921c8ed417b0c4d5edbccd2d57e23f8 Mon Sep 17 00:00:00 2001 From: Robert Ancell Date: Wed, 2 Feb 2022 14:19:06 +1300 Subject: [PATCH 4/4] Add tests for GIF files with invalid LZW code sizes --- tests/test-images/fail/overflow-codes-max.gif | Bin 0 -> 65 bytes tests/test-images/fail/overflow-codes.gif | Bin 0 -> 35 bytes tests/test-images/gif-test-suite/TESTS | 2 ++ tests/test-images/gif-test-suite/invalid-code.conf | 11 +++++++++++ tests/test-images/gif-test-suite/invalid-code.gif | Bin 0 -> 35 bytes .../gif-test-suite/overflow-codes-max.conf | 11 +++++++++++ .../gif-test-suite/overflow-codes-max.gif | Bin 0 -> 65 bytes .../test-images/gif-test-suite/overflow-codes.conf | 11 +++++++++++ .../test-images/gif-test-suite/overflow-codes.gif | Bin 0 -> 35 bytes 9 files changed, 35 insertions(+) create mode 100644 tests/test-images/fail/overflow-codes-max.gif create mode 100644 tests/test-images/fail/overflow-codes.gif create mode 100644 tests/test-images/gif-test-suite/invalid-code.conf create mode 100644 tests/test-images/gif-test-suite/invalid-code.gif create mode 100644 tests/test-images/gif-test-suite/overflow-codes-max.conf create mode 100644 tests/test-images/gif-test-suite/overflow-codes-max.gif create mode 100644 tests/test-images/gif-test-suite/overflow-codes.conf create mode 100644 tests/test-images/gif-test-suite/overflow-codes.gif diff --git a/tests/test-images/fail/overflow-codes-max.gif b/tests/test-images/fail/overflow-codes-max.gif new file mode 100644 index 0000000000000000000000000000000000000000..3d507ca7daa790c9370e69a2ab277f55d749a013 GIT binary patch literal 65 ncmZ?wbhEHbWMW`q_`m=H|NsBj0ns24hW`ozAU1Bm$Y2csUc3i2 literal 0 HcmV?d00001 diff --git a/tests/test-images/fail/overflow-codes.gif b/tests/test-images/fail/overflow-codes.gif new file mode 100644 index 0000000000000000000000000000000000000000..c38053872ae2e3378ff6fb8f3eaff839fa5d35ed GIT binary patch literal 35 jcmZ?wbhEHbWMW`q_`m=H|NsBj0ns241|B8>Mh0sDhc^Z! literal 0 HcmV?d00001 diff --git a/tests/test-images/gif-test-suite/TESTS b/tests/test-images/gif-test-suite/TESTS index 1d4a3f13f..bc573acf4 100644 --- a/tests/test-images/gif-test-suite/TESTS +++ b/tests/test-images/gif-test-suite/TESTS @@ -44,6 +44,8 @@ max-height 255-codes large-codes max-codes +#overflow-codes +#overflow-codes-max transparent invalid-transparent disabled-transparent diff --git a/tests/test-images/gif-test-suite/invalid-code.conf b/tests/test-images/gif-test-suite/invalid-code.conf new file mode 100644 index 000000000..3bf287b4e --- /dev/null +++ b/tests/test-images/gif-test-suite/invalid-code.conf @@ -0,0 +1,11 @@ +# Automatically generated, do not edit! +[config] +input = invalid-code.gif +version = GIF89a +width = 2 +height = 2 +background = #000000 +loop-count = 0 +force-animation = no +frames = + diff --git a/tests/test-images/gif-test-suite/invalid-code.gif b/tests/test-images/gif-test-suite/invalid-code.gif new file mode 100644 index 0000000000000000000000000000000000000000..7d929c9431c0c5b7cd53f636f7711d47385f88b2 GIT binary patch literal 35 jcmZ?wbhEHbWMW`q_`m=H|NsBj0ns241}3Ke{~4?Sjj;#^ literal 0 HcmV?d00001 diff --git a/tests/test-images/gif-test-suite/overflow-codes-max.conf b/tests/test-images/gif-test-suite/overflow-codes-max.conf new file mode 100644 index 000000000..f6d3f38d8 --- /dev/null +++ b/tests/test-images/gif-test-suite/overflow-codes-max.conf @@ -0,0 +1,11 @@ +# Automatically generated, do not edit! +[config] +input = overflow-codes-max.gif +version = GIF89a +width = 2 +height = 2 +background = #000000 +loop-count = 0 +force-animation = no +frames = + diff --git a/tests/test-images/gif-test-suite/overflow-codes-max.gif b/tests/test-images/gif-test-suite/overflow-codes-max.gif new file mode 100644 index 0000000000000000000000000000000000000000..3d507ca7daa790c9370e69a2ab277f55d749a013 GIT binary patch literal 65 ncmZ?wbhEHbWMW`q_`m=H|NsBj0ns24hW`ozAU1Bm$Y2csUc3i2 literal 0 HcmV?d00001 diff --git a/tests/test-images/gif-test-suite/overflow-codes.conf b/tests/test-images/gif-test-suite/overflow-codes.conf new file mode 100644 index 000000000..19f57fa74 --- /dev/null +++ b/tests/test-images/gif-test-suite/overflow-codes.conf @@ -0,0 +1,11 @@ +# Automatically generated, do not edit! +[config] +input = overflow-codes.gif +version = GIF89a +width = 2 +height = 2 +background = #000000 +loop-count = 0 +force-animation = no +frames = + diff --git a/tests/test-images/gif-test-suite/overflow-codes.gif b/tests/test-images/gif-test-suite/overflow-codes.gif new file mode 100644 index 0000000000000000000000000000000000000000..c38053872ae2e3378ff6fb8f3eaff839fa5d35ed GIT binary patch literal 35 jcmZ?wbhEHbWMW`q_`m=H|NsBj0ns241|B8>Mh0sDhc^Z! literal 0 HcmV?d00001 -- GitLab