check input validity, this prevents a few variables from reachin odd values which might have lead to out of array writes and thus might have been exploitable

Originally committed as revision 8522 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-03-25 23:37:38 +00:00
parent 34a370cb0c
commit 0cb7f8a260

View File

@ -196,7 +196,6 @@ int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){
}
c = lzw_get_code(s);
if (c == s->end_code) {
s->end_code = -1;
break;
} else if (c == s->clear_code) {
s->cursize = s->codesize + 1;
@ -206,10 +205,11 @@ int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){
fc= oc= -1;
} else {
code = c;
if (code >= s->slot) {
if (code == s->slot && fc>=0) {
*sp++ = fc;
code = oc;
}
}else if(code >= s->slot)
break;
while (code >= s->newcodes) {
*sp++ = s->suffix[code];
code = s->prefix[code];
@ -229,6 +229,7 @@ int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){
}
}
}
s->end_code = -1;
the_end:
s->sp = sp;
s->oc = oc;