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Bug 1359240 - When loading an SVG glyph, check if the SVG document is gz-compressed, and decompress before attempting to parse. r=jrmuizel

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Differential Revision: https://phabricator.services.mozilla.com/D31107

--HG--
extra : moz-landing-system : lando
This commit is contained in:
Jonathan Kew 2019-05-20 14:32:00 +00:00
parent f0dc4b3dbe
commit e82acf4503
1 changed files with 39 additions and 1 deletions
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40
gfx/thebes/gfxSVGGlyphs.cpp
View File

@ -32,6 +32,7 @@
#include "gfxFont.h"
#include "gfxContext.h"
#include "harfbuzz/hb.h"
#include "zlib.h"
#define SVG_CONTENT_TYPE NS_LITERAL_CSTRING("image/svg+xml")
#define UTF8_CHARSET NS_LITERAL_CSTRING("utf-8")
@ -257,7 +258,44 @@ gfxSVGGlyphsDocument::gfxSVGGlyphsDocument(const uint8_t* aBuffer,
uint32_t aBufLen,
gfxSVGGlyphs* aSVGGlyphs)
: mOwner(aSVGGlyphs) {
ParseDocument(aBuffer, aBufLen);
if (aBufLen >= 14 && aBuffer[0] == 31 && aBuffer[1] == 139) {
// It's a gzip-compressed document; decompress it before parsing.
// The original length (modulo 2^32) is found in the last 4 bytes
// of the data, stored in little-endian format. We read it as
// individual bytes to avoid possible alignment issues.
// (Note that if the original length was >2^32, then origLen here
// will be incorrect; but then the inflate() call will not return
// Z_STREAM_END and we'll bail out safely.)
size_t origLen = (size_t(aBuffer[aBufLen - 1]) << 24) +
(size_t(aBuffer[aBufLen - 2]) << 16) +
(size_t(aBuffer[aBufLen - 3]) << 8) +
size_t(aBuffer[aBufLen - 4]);
AutoTArray<uint8_t, 4096> outBuf;
if (outBuf.SetLength(origLen, mozilla::fallible)) {
z_stream s = {0};
s.next_in = const_cast<Byte*>(aBuffer);
s.avail_in = aBufLen;
s.next_out = outBuf.Elements();
s.avail_out = outBuf.Length();
// The magic number 16 here is the zlib flag to expect gzip format,
// see http://www.zlib.net/manual.html#Advanced
if (Z_OK == inflateInit2(&s, 16 + MAX_WBITS)) {
int result = inflate(&s, Z_FINISH);
if (Z_STREAM_END == result) {
MOZ_ASSERT(size_t(s.next_out - outBuf.Elements()) == origLen);
ParseDocument(outBuf.Elements(), outBuf.Length());
} else {
NS_WARNING("Failed to decompress SVG glyphs document");
}
inflateEnd(&s);
}
} else {
NS_WARNING("Failed to allocate memory for SVG glyphs document");
}
} else {
ParseDocument(aBuffer, aBufLen);
}
if (!mDocument) {
NS_WARNING("Could not parse SVG glyphs document");
return;