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https://git.in.rschanz.org/ryan77627/guix.git
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54 lines
2.7 KiB
Diff
54 lines
2.7 KiB
Diff
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Fix CVE-2020-29385. Note that we omit the binary test file
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tests/test-images/fail/hang_114.gif from the following commit, to avoid
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requiring 'git' to apply the patch.
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From bdd3acbd48a575d418ba6bf1b32d7bda2fae1c81 Mon Sep 17 00:00:00 2001
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From: Robert Ancell <robert.ancell@canonical.com>
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Date: Mon, 30 Nov 2020 12:26:12 +1300
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Subject: [PATCH] gif: Fix LZW decoder accepting invalid LZW code.
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The code value after a reset wasn't being validated, which means we would
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accept invalid codes. This could cause an infinite loop in the decoder.
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Fixes CVE-2020-29385
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Fixes https://gitlab.gnome.org/GNOME/gdk-pixbuf/-/issues/164
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---
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gdk-pixbuf/lzw.c | 13 +++++++------
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tests/test-images/fail/hang_114.gif | Bin 0 -> 5561 bytes
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2 files changed, 7 insertions(+), 6 deletions(-)
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create mode 100644 tests/test-images/fail/hang_114.gif
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diff --git a/gdk-pixbuf/lzw.c b/gdk-pixbuf/lzw.c
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index 9e052a6f7..105daf2b1 100644
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--- a/gdk-pixbuf/lzw.c
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+++ b/gdk-pixbuf/lzw.c
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@@ -195,19 +195,20 @@ lzw_decoder_feed (LZWDecoder *self,
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if (self->last_code != self->clear_code && self->code_table_size < MAX_CODES) {
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if (self->code < self->code_table_size)
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add_code (self, self->code);
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- else if (self->code == self->code_table_size)
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+ else
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add_code (self, self->last_code);
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- else {
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- /* Invalid code received - just stop here */
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- self->last_code = self->eoi_code;
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- return output_length;
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- }
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/* When table is full increase code size */
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if (self->code_table_size == (1 << self->code_size) && self->code_size < LZW_CODE_MAX)
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self->code_size++;
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}
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+ /* Invalid code received - just stop here */
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+ if (self->code >= self->code_table_size) {
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+ self->last_code = self->eoi_code;
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+ return output_length;
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+ }
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+
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/* Convert codeword into indexes */
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n_written += write_indexes (self, output + n_written, output_length - n_written);
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}
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