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authordgp <dgp@users.sourceforge.net>2015-05-15 15:51:20 (GMT)
committerdgp <dgp@users.sourceforge.net>2015-05-15 15:51:20 (GMT)
commita7faf9f8a33c55adb9081e5a27a31d2eae249638 (patch)
treed69914ff4650e385f782465c9589b81d24ded23f /generic/tkImgPNG.c
parent5f46d2f08eda1b81b09264e12b2fdf4a16342e2f (diff)
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[dece631375] Prevent PNG Reader writing to memory beyond end of photo image
block.
Diffstat (limited to 'generic/tkImgPNG.c')
-rw-r--r--generic/tkImgPNG.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/generic/tkImgPNG.c b/generic/tkImgPNG.c
index 8146e33..9d0fb30 100644
--- a/generic/tkImgPNG.c
+++ b/generic/tkImgPNG.c
@@ -2092,7 +2092,8 @@ ReadIDAT(
* Process IDAT contents until there is no more in this chunk.
*/
- while (chunkSz && !Tcl_ZlibStreamEof(pngPtr->stream)) {
+ while (chunkSz && !Tcl_ZlibStreamEof(pngPtr->stream)
+ && pngPtr->currentLine < pngPtr->block.height) {
int len1, len2;
/*
@@ -2178,10 +2179,13 @@ ReadIDAT(
/*
* Try to read another line of pixels out of the buffer
- * immediately.
+ * immediately, but don't allow write past end of block.
*/
- goto getNextLine;
+ if (pngPtr->currentLine < pngPtr->block.height) {
+ goto getNextLine;
+ }
+
}
/*