new file mode 100644
@@ -0,0 +1,191 @@
+From 8708b9e081192786c027bb7f5f23d76dbe5c19e8 Mon Sep 17 00:00:00 2001
+From: Behdad Esfahbod <behdad@behdad.org>
+Date: Mon, 6 Feb 2023 14:51:25 -0700
+Subject: [PATCH] [GPOS] Avoid O(n^2) behavior in mark-attachment
+
+Better implementation; avoids arbitrary limit on look-back.
+Upstream-Status: Backport from [https://github.com/harfbuzz/harfbuzz/commit/8708b9e081192786c027bb7f5f23d76dbe5c19e8]
+CVE: CVE-2023-25193
+Signed-off-by: Siddharth Doshi <sdoshi@mvista.com>
+---
+ src/OT/Layout/GPOS/MarkBasePosFormat1.hh | 76 +++++++++++++++---------
+ src/OT/Layout/GPOS/MarkLigPosFormat1.hh | 24 ++++++--
+ src/hb-ot-layout-gsubgpos.hh | 5 +-
+ 3 files changed, 69 insertions(+), 36 deletions(-)
+
+diff --git a/src/OT/Layout/GPOS/MarkBasePosFormat1.hh b/src/OT/Layout/GPOS/MarkBasePosFormat1.hh
+index ebb8c31..73839a4 100644
+--- a/src/OT/Layout/GPOS/MarkBasePosFormat1.hh
++++ b/src/OT/Layout/GPOS/MarkBasePosFormat1.hh
+@@ -90,6 +90,25 @@ struct MarkBasePosFormat1_2
+
+ const Coverage &get_coverage () const { return this+markCoverage; }
+
++ static inline bool accept (hb_buffer_t *buffer, unsigned idx)
++ {
++ /* We only want to attach to the first of a MultipleSubst sequence.
++ * https://github.com/harfbuzz/harfbuzz/issues/740
++ * Reject others...
++ * ...but stop if we find a mark in the MultipleSubst sequence:
++ * https://github.com/harfbuzz/harfbuzz/issues/1020 */
++ return !_hb_glyph_info_multiplied (&buffer->info[idx]) ||
++ 0 == _hb_glyph_info_get_lig_comp (&buffer->info[idx]) ||
++ (idx == 0 ||
++ _hb_glyph_info_is_mark (&buffer->info[idx - 1]) ||
++ !_hb_glyph_info_multiplied (&buffer->info[idx - 1]) ||
++ _hb_glyph_info_get_lig_id (&buffer->info[idx]) !=
++ _hb_glyph_info_get_lig_id (&buffer->info[idx - 1]) ||
++ _hb_glyph_info_get_lig_comp (&buffer->info[idx]) !=
++ _hb_glyph_info_get_lig_comp (&buffer->info[idx - 1]) + 1
++ );
++ }
++
+ bool apply (hb_ot_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+@@ -97,48 +116,47 @@ struct MarkBasePosFormat1_2
+ unsigned int mark_index = (this+markCoverage).get_coverage (buffer->cur().codepoint);
+ if (likely (mark_index == NOT_COVERED)) return_trace (false);
+
+- /* Now we search backwards for a non-mark glyph */
++ /* Now we search backwards for a non-mark glyph.
++ * We don't use skippy_iter.prev() to avoid O(n^2) behavior. */
++
+ hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+- skippy_iter.reset (buffer->idx, 1);
+ skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
+- do {
+- unsigned unsafe_from;
+- if (!skippy_iter.prev (&unsafe_from))
++
++ unsigned j;
++ for (j = buffer->idx; j > c->last_base_until; j--)
++ {
++ auto match = skippy_iter.match (buffer->info[j - 1]);
++ if (match == skippy_iter.MATCH)
+ {
+- buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
+- return_trace (false);
++ if (!accept (buffer, j - 1))
++ match = skippy_iter.SKIP;
+ }
++ if (match == skippy_iter.MATCH)
++ {
++ c->last_base = (signed) j - 1;
++ break;
++ }
++ }
++ c->last_base_until = buffer->idx;
++ if (c->last_base == -1)
++ {
++ buffer->unsafe_to_concat_from_outbuffer (0, buffer->idx + 1);
++ return_trace (false);
++ }
+
+- /* We only want to attach to the first of a MultipleSubst sequence.
+- * https://github.com/harfbuzz/harfbuzz/issues/740
+- * Reject others...
+- * ...but stop if we find a mark in the MultipleSubst sequence:
+- * https://github.com/harfbuzz/harfbuzz/issues/1020 */
+- if (!_hb_glyph_info_multiplied (&buffer->info[skippy_iter.idx]) ||
+- 0 == _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) ||
+- (skippy_iter.idx == 0 ||
+- _hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx - 1]) ||
+- !_hb_glyph_info_multiplied (&buffer->info[skippy_iter.idx - 1]) ||
+- _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx]) !=
+- _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx - 1]) ||
+- _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) !=
+- _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx - 1]) + 1
+- ))
+- break;
+- skippy_iter.reject ();
+- } while (true);
++ unsigned idx = (unsigned) c->last_base;
+
+ /* Checking that matched glyph is actually a base glyph by GDEF is too strong; disabled */
+- //if (!_hb_glyph_info_is_base_glyph (&buffer->info[skippy_iter.idx])) { return_trace (false); }
++ //if (!_hb_glyph_info_is_base_glyph (&buffer->info[idx])) { return_trace (false); }
+
+- unsigned int base_index = (this+baseCoverage).get_coverage (buffer->info[skippy_iter.idx].codepoint);
++ unsigned int base_index = (this+baseCoverage).get_coverage (buffer->info[idx].codepoint);
+ if (base_index == NOT_COVERED)
+ {
+- buffer->unsafe_to_concat_from_outbuffer (skippy_iter.idx, buffer->idx + 1);
++ buffer->unsafe_to_concat_from_outbuffer (idx, buffer->idx + 1);
+ return_trace (false);
+ }
+
+- return_trace ((this+markArray).apply (c, mark_index, base_index, this+baseArray, classCount, skippy_iter.idx));
++ return_trace ((this+markArray).apply (c, mark_index, base_index, this+baseArray, classCount, idx));
+ }
+
+ bool subset (hb_subset_context_t *c) const
+diff --git a/src/OT/Layout/GPOS/MarkLigPosFormat1.hh b/src/OT/Layout/GPOS/MarkLigPosFormat1.hh
+index 1a80212..4471871 100644
+--- a/src/OT/Layout/GPOS/MarkLigPosFormat1.hh
++++ b/src/OT/Layout/GPOS/MarkLigPosFormat1.hh
+@@ -100,20 +100,32 @@ struct MarkLigPosFormat1_2
+ if (likely (mark_index == NOT_COVERED)) return_trace (false);
+
+ /* Now we search backwards for a non-mark glyph */
++
+ hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
+- skippy_iter.reset (buffer->idx, 1);
+ skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
+- unsigned unsafe_from;
+- if (!skippy_iter.prev (&unsafe_from))
++
++ unsigned j;
++ for (j = buffer->idx; j > c->last_base_until; j--)
+ {
+- buffer->unsafe_to_concat_from_outbuffer (unsafe_from, buffer->idx + 1);
++ auto match = skippy_iter.match (buffer->info[j - 1]);
++ if (match == skippy_iter.MATCH)
++ {
++ c->last_base = (signed) j - 1;
++ break;
++ }
++ }
++ c->last_base_until = buffer->idx;
++ if (c->last_base == -1)
++ {
++ buffer->unsafe_to_concat_from_outbuffer (0, buffer->idx + 1);
+ return_trace (false);
+ }
+
++ j = (unsigned) c->last_base;
++
+ /* Checking that matched glyph is actually a ligature by GDEF is too strong; disabled */
+- //if (!_hb_glyph_info_is_ligature (&buffer->info[skippy_iter.idx])) { return_trace (false); }
++ //if (!_hb_glyph_info_is_ligature (&buffer->info[j])) { return_trace (false); }
+
+- unsigned int j = skippy_iter.idx;
+ unsigned int lig_index = (this+ligatureCoverage).get_coverage (buffer->info[j].codepoint);
+ if (lig_index == NOT_COVERED)
+ {
+diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
+index c77ec12..b009f43 100644
+--- a/src/hb-ot-layout-gsubgpos.hh
++++ b/src/hb-ot-layout-gsubgpos.hh
+@@ -687,6 +687,9 @@ struct hb_ot_apply_context_t :
+ uint32_t random_state = 1;
+ unsigned new_syllables = (unsigned) -1;
+
++ signed last_base = -1; // GPOS uses
++ unsigned last_base_until = 0; // GPOS uses
++
+ hb_ot_apply_context_t (unsigned int table_index_,
+ hb_font_t *font_,
+ hb_buffer_t *buffer_) :
+@@ -724,7 +727,7 @@ struct hb_ot_apply_context_t :
+ iter_context.init (this, true);
+ }
+
+- void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; init_iters (); }
++ void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; last_base = -1; last_base_until = 0; init_iters (); }
+ void set_auto_zwj (bool auto_zwj_) { auto_zwj = auto_zwj_; init_iters (); }
+ void set_auto_zwnj (bool auto_zwnj_) { auto_zwnj = auto_zwnj_; init_iters (); }
+ void set_per_syllable (bool per_syllable_) { per_syllable = per_syllable_; init_iters (); }
+--
+2.25.1
+
@@ -10,6 +10,7 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=6ee0f16281694fb6aa689cca1e0fb3da \
SRC_URI = "${GITHUB_BASE_URI}/download/${PV}/${BPN}-${PV}.tar.xz \
file://0001-fix-signedness-of-char-in-tests.patch \
+ file://CVE-2023-25193.patch \
"
SRC_URI[sha256sum] = "2edb95db668781aaa8d60959d21be2ff80085f31b12053cdd660d9a50ce84f05"