From 82e17d87f061014b3c07140fafe78eaaf2fbe39d Mon Sep 17 00:00:00 2001 From: Jean-Michel Trivi Date: Fri, 12 Jan 2018 10:08:32 -0800 Subject: [PATCH] MPEG-4 AAC Decoder: check against invalid height info In CProgramConfig_ReadHeightExt prevent stack overflow from invalid FrontElementHeightInfo array value. Bug: 70637599 Test: see bug Change-Id: I145414d81d7a7be711672c12f44b537c12eea308 --- libMpegTPDec/src/tpdec_asc.cpp | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/libMpegTPDec/src/tpdec_asc.cpp b/libMpegTPDec/src/tpdec_asc.cpp index 96a1b35..e80d0e5 100644 --- a/libMpegTPDec/src/tpdec_asc.cpp +++ b/libMpegTPDec/src/tpdec_asc.cpp @@ -118,7 +118,9 @@ int CProgramConfig_IsValid ( const CProgramConfig *pPce ) /* * Read the extension for height info. - * return 0 if successfull or -1 if the CRC failed. + * return 0 if successfull, + * -1 if the CRC failed, + * -2 if invalid HeightInfo. */ static int CProgramConfig_ReadHeightExt( @@ -146,15 +148,21 @@ int CProgramConfig_ReadHeightExt( for (i=0; i < pPce->NumFrontChannelElements; i++) { - pPce->FrontElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2); + if ((pPce->FrontElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2)) >= PC_NUM_HEIGHT_LAYER) { + err = -2; /* height information is out of the valid range */ + } } for (i=0; i < pPce->NumSideChannelElements; i++) { - pPce->SideElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2); + if ((pPce->SideElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2)) >= PC_NUM_HEIGHT_LAYER) { + err = -2; /* height information is out of the valid range */ + } } for (i=0; i < pPce->NumBackChannelElements; i++) { - pPce->BackElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2); + if ((pPce->BackElementHeightInfo[i] = (UCHAR) FDKreadBits(bs,2)) >= PC_NUM_HEIGHT_LAYER) { + err = -2; /* height information is out of the valid range */ + } } FDKbyteAlign(bs, alignmentAnchor); @@ -163,6 +171,13 @@ int CProgramConfig_ReadHeightExt( /* CRC failed */ err = -1; } + if (err!=0) { + /* Reset whole height information in case an error occured during parsing. The return + value ensures that pPce->isValid is set to 0 and implicit channel mapping is used. */ + FDKmemclear(pPce->FrontElementHeightInfo, sizeof(pPce->FrontElementHeightInfo)); + FDKmemclear(pPce->SideElementHeightInfo, sizeof(pPce->SideElementHeightInfo)); + FDKmemclear(pPce->BackElementHeightInfo, sizeof(pPce->BackElementHeightInfo)); + } } else { /* No valid extension data found -> restore the initial bitbuffer state */