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Merge pull request #708 from GrokImageCompression/issue_695 

issue #695 MQ Encode: ensure that bp pointer never points to uninitialized memory
This commit is contained in:
Antonin Descampe 2016-04-18 10:51:51 +02:00
parent a1c0ee9a86 0069a2bd2f
commit e1a93d9e59
1 changed files with 9 additions and 5 deletions
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14
src/lib/openjp2/mqc.c
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@ -203,13 +203,20 @@ static opj_mqc_state_t mqc_states[47 * 2] = {
*/ */
static void opj_mqc_byteout(opj_mqc_t *mqc) { static void opj_mqc_byteout(opj_mqc_t *mqc) {
if (*mqc->bp == 0xff) { /* avoid accessing uninitialized memory*/
if (mqc->bp == mqc->start-1) {
mqc->bp++;
*mqc->bp = (OPJ_BYTE)(mqc->c >> 19);
mqc->c &= 0x7ffff;
mqc->ct = 8;
}
else if (*mqc->bp == 0xff) {
mqc->bp++; mqc->bp++;
*mqc->bp = (OPJ_BYTE)(mqc->c >> 20); *mqc->bp = (OPJ_BYTE)(mqc->c >> 20);
mqc->c &= 0xfffff; mqc->c &= 0xfffff;
mqc->ct = 7; mqc->ct = 7;
} else { } else {
if ((mqc->c & 0x8000000) == 0) { /* ((mqc->c&0x8000000)==0) CHANGE */ if ((mqc->c & 0x8000000) == 0) {
mqc->bp++; mqc->bp++;
*mqc->bp = (OPJ_BYTE)(mqc->c >> 19); *mqc->bp = (OPJ_BYTE)(mqc->c >> 19);
mqc->c &= 0x7ffff; mqc->c &= 0x7ffff;
@ -395,9 +402,6 @@ void opj_mqc_init_enc(opj_mqc_t *mqc, OPJ_BYTE *bp) {
mqc->c = 0; mqc->c = 0;
mqc->bp = bp - 1; mqc->bp = bp - 1;
mqc->ct = 12; mqc->ct = 12;
if (*mqc->bp == 0xff) {
mqc->ct = 13;
}
mqc->start = bp; mqc->start = bp;
} }