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Bug 251381 - libpng buffer overflow vulnerabilities.

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p=glennrp,tor; r=glennrp,tor; sr=tor
This commit is contained in:
tor%cs.brown.edu 2004-08-04 14:02:34 +00:00
parent 1eb17bb680
commit 49e8786590
1 changed files with 36 additions and 0 deletions
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36
modules/libpr0n/decoders/png/nsPNGDecoder.cpp
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@ -89,6 +89,24 @@ nsPNGDecoder::~nsPNGDecoder()
/* void init (in imgILoad aLoad); */
NS_IMETHODIMP nsPNGDecoder::Init(imgILoad *aLoad)
{
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
static png_byte unused_chunks[]=
{ 98, 75, 71, 68, '\0', /* bKGD */
99, 72, 82, 77, '\0', /* cHRM */
104, 73, 83, 84, '\0', /* hIST */
105, 67, 67, 80, '\0', /* iCCP */
105, 84, 88, 116, '\0', /* iTXt */
111, 70, 70, 115, '\0', /* oFFs */
112, 67, 65, 76, '\0', /* pCAL */
115, 67, 65, 76, '\0', /* sCAL */
112, 72, 89, 115, '\0', /* pHYs */
115, 66, 73, 84, '\0', /* sBIT */
115, 80, 76, 84, '\0', /* sPLT */
116, 69, 88, 116, '\0', /* tEXt */
116, 73, 77, 69, '\0', /* tIME */
122, 84, 88, 116, '\0'}; /* zTXt */
#endif
mImageLoad = aLoad;
mObserver = do_QueryInterface(aLoad); // we're holding 2 strong refs to the request.
@ -109,6 +127,12 @@ NS_IMETHODIMP nsPNGDecoder::Init(imgILoad *aLoad)
return NS_ERROR_OUT_OF_MEMORY;
}
#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
/* Ignore unused chunks */
png_set_keep_unknown_chunks(mPNG, 0, unused_chunks,
(int)sizeof(unused_chunks)/5);
#endif
/* use this as libpng "progressive pointer" (retrieve in callbacks) */
png_set_progressive_read_fn(mPNG, NS_STATIC_CAST(png_voidp, this),
info_callback, row_callback, end_callback);
@ -198,6 +222,15 @@ info_callback(png_structp png_ptr, png_infop info_ptr)
png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, &compression_type, &filter_type);
/* limit image dimensions (bug #251381) */
#define MOZ_PNG_MAX_DIMENSION 1000000L
if (width > MOZ_PNG_MAX_DIMENSION || height > MOZ_PNG_MAX_DIMENSION) {
nsPNGDecoder *decoder = NS_STATIC_CAST(nsPNGDecoder*,
png_get_progressive_ptr(png_ptr));
longjmp(decoder->mPNG->jmpbuf, 1);
}
#undef MOZ_PNG_MAX_DIMENSION
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand(png_ptr);
@ -529,5 +562,8 @@ error_callback(png_structp png_ptr, png_const_charp error_msg)
void
warning_callback(png_structp png_ptr, png_const_charp warning_msg)
{
/* convert tRNS warning to error (bug #251381) */
if (strncmp(warning_msg, "Missing PLTE before tRNS", 24) == 0)
png_error(png_ptr, warning_msg);
PR_LOG(gPNGLog, PR_LOG_WARNING, ("libpng warning: %s\n", warning_msg));
}