SkRegion: change serialization unit tests, better validation code
Also: Don't alloc before validation.
Change-Id: Ic2e007ecf4e06fb099366295b963f66df3f7903a
Reviewed-on: https://skia-review.googlesource.com/8728
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/src/core/SkRegion.cpp b/src/core/SkRegion.cpp
index dca9b9d..e873ebb 100644
--- a/src/core/SkRegion.cpp
+++ b/src/core/SkRegion.cpp
@@ -1129,37 +1129,113 @@
return buffer.pos();
}
+// Validate that a memory sequence is a valid region.
+// Try to check all possible errors.
+// never read beyond &runs[runCount-1].
+static bool validate_run(const int32_t* runs,
+ int runCount,
+ const SkIRect& givenBounds,
+ int32_t ySpanCount,
+ int32_t intervalCount) {
+ // Region Layout:
+ // Top ( Bottom Span_Interval_Count ( Left Right )* Sentinel )+ Sentinel
+ if (ySpanCount < 1 || intervalCount < 2 || runCount != 2 + 3 * ySpanCount + 2 * intervalCount) {
+ return false;
+ }
+ SkASSERT(runCount >= 7); // 7==SkRegion::kRectRegionRuns
+ // quick sanity check:
+ if (runs[runCount - 1] != SkRegion::kRunTypeSentinel ||
+ runs[runCount - 2] != SkRegion::kRunTypeSentinel) {
+ return false;
+ }
+ const int32_t* const end = runs + runCount;
+ SkIRect bounds = {0, 0, 0 ,0}; // calulated bounds
+ SkIRect rect = {0, 0, 0, 0}; // current rect
+ rect.fTop = *runs++;
+ if (rect.fTop == SkRegion::kRunTypeSentinel) {
+ return false; // no rect can contain SkRegion::kRunTypeSentinel
+ }
+ do {
+ --ySpanCount;
+ if (ySpanCount < 0) {
+ return false; // too many yspans
+ }
+ rect.fBottom = *runs++;
+ if (rect.fBottom == SkRegion::kRunTypeSentinel) {
+ return false;
+ }
+ int32_t xIntervals = *runs++;
+ SkASSERT(runs < end);
+ if (xIntervals < 0 || runs + 1 + 2 * xIntervals > end) {
+ return false;
+ }
+ intervalCount -= xIntervals;
+ if (intervalCount < 0) {
+ return false; // too many intervals
+ }
+ while (xIntervals-- > 0) {
+ rect.fLeft = *runs++;
+ rect.fRight = *runs++;
+ if (rect.fLeft == SkRegion::kRunTypeSentinel ||
+ rect.fRight == SkRegion::kRunTypeSentinel || rect.isEmpty()) {
+ return false;
+ }
+ bounds.join(rect);
+ }
+ if (*runs++ != SkRegion::kRunTypeSentinel) {
+ return false; // required check sentinal.
+ }
+ rect.fTop = rect.fBottom;
+ SkASSERT(runs < end);
+ } while (*runs != SkRegion::kRunTypeSentinel);
+ ++runs;
+ if (ySpanCount != 0 || intervalCount != 0 || givenBounds != bounds) {
+ return false;
+ }
+ SkASSERT(runs == end); // if ySpanCount && intervalCount are right, must be correct length.
+ return true;
+}
size_t SkRegion::readFromMemory(const void* storage, size_t length) {
SkRBuffer buffer(storage, length);
SkRegion tmp;
int32_t count;
- if (buffer.readS32(&count) && (count >= 0) && buffer.read(&tmp.fBounds, sizeof(tmp.fBounds))) {
- if (tmp.fBounds.isEmpty()) {
- return 0; // bad bounds for non-empty region; report failure
+ // Serialized Region Format:
+ // Empty:
+ // -1
+ // Simple Rect:
+ // 0 LEFT TOP RIGHT BOTTOM
+ // Complex Region:
+ // COUNT LEFT TOP RIGHT BOTTOM Y_SPAN_COUNT TOTAL_INTERVAL_COUNT [RUNS....]
+ if (!buffer.readS32(&count) || count < -1) {
+ return 0;
+ }
+ if (count >= 0) {
+ if (!buffer.read(&tmp.fBounds, sizeof(tmp.fBounds)) || tmp.fBounds.isEmpty()) {
+ return 0; // Short buffer or bad bounds for non-empty region; report failure.
}
if (count == 0) {
tmp.fRunHead = SkRegion_gRectRunHeadPtr;
} else {
int32_t ySpanCount, intervalCount;
- if (buffer.readS32(&ySpanCount) && buffer.readS32(&intervalCount) &&
- intervalCount > 1) {
- tmp.allocateRuns(count, ySpanCount, intervalCount);
- if (!tmp.isComplex()) {
- return 0; // report failure
- }
- buffer.read(tmp.fRunHead->writable_runs(), count * sizeof(RunType));
- } else {
- return 0; // report failure;
+ if (!buffer.readS32(&ySpanCount) ||
+ !buffer.readS32(&intervalCount) ||
+ buffer.available() < count * sizeof(int32_t)) {
+ return 0;
}
+ if (!validate_run((const int32_t*)((const char*)storage + buffer.pos()), count,
+ tmp.fBounds, ySpanCount, intervalCount)) {
+ return 0; // invalid runs, don't even allocate
+ }
+ tmp.allocateRuns(count, ySpanCount, intervalCount);
+ SkASSERT(tmp.isComplex());
+ SkAssertResult(buffer.read(tmp.fRunHead->writable_runs(), count * sizeof(int32_t)));
}
}
- size_t sizeRead = 0;
- if (buffer.isValid() && tmp.isValid()) {
- this->swap(tmp);
- sizeRead = buffer.pos();
- }
- return sizeRead;
+ SkASSERT(tmp.isValid());
+ SkASSERT(buffer.isValid());
+ this->swap(tmp);
+ return buffer.pos();
}
///////////////////////////////////////////////////////////////////////////////
@@ -1171,110 +1247,19 @@
///////////////////////////////////////////////////////////////////////////////
-// Starts with first X-interval, and returns a ptr to the X-sentinel
-static const SkRegion::RunType* skip_intervals_slow(const SkRegion::RunType runs[]) {
- // want to track that our intevals are all disjoint, such that
- // prev-right < next-left. We rely on this optimization in places such as
- // contains().
- //
- SkRegion::RunType prevR = -SkRegion::kRunTypeSentinel;
-
- while (runs[0] < SkRegion::kRunTypeSentinel) {
- if (prevR >= runs[0]
- || runs[0] >= runs[1]
- || runs[1] >= SkRegion::kRunTypeSentinel) {
- return nullptr;
- }
- prevR = runs[1];
- runs += 2;
- }
- return runs;
-}
-
-static bool compute_bounds(const SkRegion::RunType runs[],
- SkIRect* bounds, int* ySpanCountPtr,
- int* intervalCountPtr) {
- SkASSERT(bounds && ySpanCountPtr && intervalCountPtr);
- if (SkRegionValueIsSentinel(runs[0])) { return false; }
-
- int left = SK_MaxS32;
- int rite = SK_MinS32;
- int bot;
- int ySpanCount = 0;
- int intervalCount = 0;
-
- if (!runs) { return false; }
- bounds->fTop = *runs++;
- do {
- bot = *runs++;
- if (SkRegion::kRunTypeSentinel <= bot) { return false; }
-
- ySpanCount += 1;
-
- runs += 1; // skip intervalCount for now
- if (*runs < SkRegion::kRunTypeSentinel) {
- if (left > *runs) {
- left = *runs;
- }
-
- const SkRegion::RunType* prev = runs;
- runs = skip_intervals_slow(runs);
- if (!runs) { return false; }
- int intervals = SkToInt((runs - prev) >> 1);
- if (prev[-1] != intervals) { return false; }
- intervalCount += intervals;
-
- if (rite < runs[-1]) {
- rite = runs[-1];
- }
- } else { // no intervals
- if (0 != runs[-1]) {
- return false;
- }
- }
- if (SkRegion::kRunTypeSentinel != *runs) {
- return false;
- }
- runs += 1;
- } while (SkRegion::kRunTypeSentinel != *runs);
-
- bounds->fLeft = left;
- bounds->fRight = rite;
- bounds->fBottom = bot;
- *ySpanCountPtr = ySpanCount;
- *intervalCountPtr = intervalCount;
- return true;
-}
-
bool SkRegion::isValid() const {
if (this->isEmpty()) {
- // check for explicit empty (the zero rect), so we can compare rects to know when
- // two regions are equal (i.e. emptyRectA == emptyRectB)
- // this is stricter than just asserting fBounds.isEmpty()
return fBounds == SkIRect{0, 0, 0, 0};
- } else {
- if (fBounds.isEmpty()) {
- return false;
- }
- if (!this->isRect()) {
- if (!fRunHead
- || fRunHead->fRefCnt < 1
- || fRunHead->fRunCount <= kRectRegionRuns) {
- return false;
- }
- const RunType* run = fRunHead->readonly_runs();
- // check that our bounds match our runs
- SkIRect bounds;
- int ySpanCount, intervalCount;
- return compute_bounds(run, &bounds, &ySpanCount, &intervalCount)
- && bounds == fBounds
- && ySpanCount > 0
- && fRunHead->getYSpanCount() == ySpanCount
- && fRunHead->getIntervalCount() == intervalCount;
- } else {
- return true;
- }
}
+ if (fBounds.isEmpty()) {
+ return false;
+ }
+ if (this->isRect()) {
+ return true;
+ }
+ return fRunHead && fRunHead->fRefCnt > 0 &&
+ validate_run(fRunHead->readonly_runs(), fRunHead->fRunCount, fBounds,
+ fRunHead->getYSpanCount(), fRunHead->getIntervalCount());
}
#ifdef SK_DEBUG
diff --git a/tests/RegionTest.cpp b/tests/RegionTest.cpp
index f2a3d02..2a5d0a5 100644
--- a/tests/RegionTest.cpp
+++ b/tests/RegionTest.cpp
@@ -295,6 +295,17 @@
REPORTER_ASSERT(r, nonEmpty);
REPORTER_ASSERT(r, region.isComplex());
test_write(region, r);
+
+ SkRegion complexRegion;
+ Union(&complexRegion, SkIRect::MakeXYWH(0, 0, 1, 1));
+ Union(&complexRegion, SkIRect::MakeXYWH(0, 0, 3, 3));
+ Union(&complexRegion, SkIRect::MakeXYWH(10, 0, 3, 3));
+ Union(&complexRegion, SkIRect::MakeXYWH(0, 10, 13, 3));
+ test_write(complexRegion, r);
+
+ Union(&complexRegion, SkIRect::MakeXYWH(10, 20, 3, 3));
+ Union(&complexRegion, SkIRect::MakeXYWH(0, 20, 3, 3));
+ test_write(complexRegion, r);
}
DEF_TEST(Region_readFromMemory_bad, r) {
@@ -302,50 +313,54 @@
// and might need to remove or change some of these tests.
SkRegion region;
- static const char data0[] =
- "\2\0\0\0\277]\345\222\\\2G\252\0\177'\10\203\236\211>\377\340@\351"
- "!\370y\3\31\232r\353\343\336Ja\177\377\377\377\244\301\362:Q\\\0\0"
- "\1\200\263\214\374\276\336P\225^\230\20UH N\265\357\177\240\0\306\377"
- "\177\346\222S \0\375\0\332\247 \302I\240H\374\200lk\r`\0375\324W\215"
- "\270tE^,\224n\310fy\377\231AH\16\235A\371\315\347\360\265\372r\232"
- "\301\216\35\227:\265]\32\20W\263yc\207\246\270tE^,\224n\310sy\2\0A"
- "\14\241SQ\\\303\364\0\0\1\200\0\0\374k\r`\0375\324Wp\270\267\313\313"
- "\313\313\313@\277\365b\341\343\336Ja\357~\263\0\2\333\260\220\\\303"
- "\364\265\332\267\242\325nlX\367\27I4444;\266\256\37/M\207";
- size_t data0length = 221;
- REPORTER_ASSERT(r, 0 == region.readFromMemory(data0, data0length));
-
- static const char data1[] =
- "\2\0\0\0\\\2G\252\0\177'\10\247 \302I\240H\374\200lk\r`\0375\324Wr"
- "\232\301\216\35\227:\265]\32\20W\263yc\207\246\270tE^,\224n\310sy\2"
- "\0A\14\241SQ\\\303\364\0\0\1\200\0\0\374k\r`\0375\324Wp\270\267\313"
- "\313\313\313\313@\277\365b\341\343\336Ja\357~\263\0\2\333\260\220\\"
- "\303\364\265\332\267\242\325nlX\367\27I4444;\266\256\37/M\207";
- size_t data1length = 129;
- REPORTER_ASSERT(r, 0 == region.readFromMemory(data1, data1length));
-
- static const char data2[] =
- " \0\0\0`\6\363\234AH\26\235\0\0\0\0\251\217\27I\27C\361,\320u\3171"
- "\10.\206\277]\345\222\334\2C\252\242a'\10\251\31\326\372\334A\277\30"
- "\240M\275v\201\271\3527\215{)S\3771{\345Z\250\23\213\331\23j@\13\220"
- "\200Z^-\20\212=;\355\314\36\260c\224M\16\271Szy\373\204M\21\177\251"
- "\275\r\274M\370\201\243^@\343\236JaS\204\3212\244\301\327\22\352KI"
- "\207\350z\300\250\372\26\14\2\233K\330\16\251\230\223\r\"\243\271\17"
- ")\260\262\2[a.*.4\14\344\307\350\3\0\0-\350G!\31\300\205\205\205\205"
- "\205\205\205\205\205\205\205\205\205\205\205\205\305m\311<Q\347\30"
- "\324\203f\2614\3115\206\214@:\346n\254\37\225\263\214\374\276\336\23"
- "\270\304\262\25\24_\342\223\253\351L\30\372\373\243\240g\0367V\336"
- "P\7-1{\345Z\250\23\213P\225^\230\27UH\206N\265\357\177\262\302\306"
- "kk\7\233\234N\32@\355H\327\34\337\0V\30 \225\35\225\233\253\0144>\310"
- "\352\346L\232\215\270t[^,\224l\312f\2025?}\1ZL\217wf8C\346\222S\240"
- "\203\375\374\332\247 \302I\271H\0\0lk\22`\0375\324W\374\265\342\243"
- "yL\211\215\270tE^,\224l\312f\2025?}\1ZL\217wf8C\333\370_.\277A\277"
- "^\\\313!\342\340\213\210\244\272\33\275\360\301\347\315\377\6a\272"
- "kyi:W\332\366\5\312F\217c\243\20,\"\240\347o\375\277\317}HEji\367\374"
- "\331\214\314\242x\356\340\350\362r$\222\266\325\201\234\267P\243N\361"
- "++++++++\370+@++\205!8B\255L\3\3416\335$\\\r\265W[F\326\316w{.\306"
- ">f2i\244\242=Y\236\364\302\357xR:Q\\\303\364\265\332\200\242\325nl"
- "X\373\307\5<-";
- size_t data2length = 512;
- REPORTER_ASSERT(r, 0 == region.readFromMemory(data2, data2length));
+ {
+ // invalid boundary rectangle
+ int32_t data[5] = {0, 4, 4, 8, 2};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ // Region Layout, Serialized Format:
+ // COUNT LEFT TOP RIGHT BOTTOM Y_SPAN_COUNT TOTAL_INTERVAL_COUNT
+ // Top ( Bottom Span_Interval_Count ( Left Right )* Sentinel )+ Sentinel
+ {
+ // Example of valid data
+ int32_t data[] = {9, 0, 0, 10, 10, 1, 2, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, 2147483647};
+ REPORTER_ASSERT(r, 0 != region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // Short count
+ int32_t data[] = {8, 0, 0, 10, 10, 1, 2, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, 2147483647};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // bounds don't match
+ int32_t data[] = {9, 0, 0, 10, 11, 1, 2, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, 2147483647};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // bad yspan count
+ int32_t data[] = {9, 0, 0, 10, 10, 2, 2, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, 2147483647};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // bad int count
+ int32_t data[] = {9, 0, 0, 10, 10, 1, 3, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, 2147483647};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // bad final sentinal
+ int32_t data[] = {9, 0, 0, 10, 10, 1, 2, 0, 10, 2, 0, 4, 6, 10,
+ 2147483647, -1};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
+ {
+ // bad row sentinal
+ int32_t data[] = {9, 0, 0, 10, 10, 1, 2, 0, 10, 2, 0, 4, 6, 10,
+ -1, 2147483647};
+ REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+ }
}