memset typo in md5.c

[philburk]

src/libFLAC/md5.c, line 266 you can find:

memset(ctx, 0, sizeof(ctx));    /* In case it's sensitive */
if(0 != ctx->internal_buf) {
    free(ctx->internal_buf);
    ctx->internal_buf = 0;
    ctx->capacity = 0;
}

That memset does not clear the entire structure. It only clears 4 or 8 bytes, depending on the size of the ctx pointer. It should use sizeof(*ctx) not sizeof(ctx). This is old bug from the original md5.c.

Note that the code that follows relies on the bug. If the memset bug is fixed then there could be a memory leak of the internal_buf. I suggest that the memset should be fixed and moved after the internal_buf code.

This should work:

if(0 != ctx->internal_buf) {
    free(ctx->internal_buf);
    ctx->internal_buf = 0;
    ctx->capacity = 0;
}
memset(ctx, 0, sizeof(*ctx));   /* In case it's sensitive */