libnvpair_json tickles incompatibilities between JSON parsers by representing 64 bit numbers as numbers

[grahamc]

System information

Type	Version/Name
Distribution Name	NixOS
Distribution Version	20.09
Linux Kernel	5.10.15
Architecture	x86_64
ZFS Version	2.0.2-1
SPL Version	2.0.2-1

(but this is all fairly irrelevant)

Describe the problem you're observing

The libnvpair_json library code uses numbers for large numbers:

zfs/lib/libnvpair/libnvpair_json.c

Lines 192 to 216 in 5b52516

	case DATA_TYPE_INT64: {
	FPRINTF(fp, "%lld",
	(long long)fnvpair_value_int64(curr));
	break;
	}
	case DATA_TYPE_UINT64: {
	FPRINTF(fp, "%llu",
	(unsigned long long)fnvpair_value_uint64(curr));
	break;
	}
	case DATA_TYPE_HRTIME: {
	hrtime_t val;
	VERIFY0(nvpair_value_hrtime(curr, &val));
	FPRINTF(fp, "%llu", (unsigned long long)val);
	break;
	}
	case DATA_TYPE_DOUBLE: {
	double val;
	VERIFY0(nvpair_value_double(curr, &val));
	FPRINTF(fp, "%f", val);
	break;
	}

However, JavaScript represents all numbers as floating point, with a 53 bit mantissa. This means that integers in JSON which are larger than 2^53 are truncated.Some non-JavaScript JSON parsers try to carefully match the semantics of JavaScript and can introduce these mysteries.

See: https://rachelbythebay.com/w/2021/02/03/bits/

Describe how to reproduce the problem

1. Create a ZFS Channel Program which emits some large numbers as json
2. Consume that JSON via various parsers

[IvanVolosyuk]

So, you mean it should quote and present them as strings?

[grahamc]

Unfortunately, yes.

[scineram]

@richardelling Laugh!

[grahamc]

@scineram is there context that I'm missing? :)

[scineram]

#7281 (comment)

[h1z1]

Yikes..

# zfs program -j  thumper zfs_rlist.zcp  thumper/tank foo:
	{"return":{"succeeded":{"thumper/tank":"9223372036854775808"},"failed":{}}}

# python -m json.tool
	9223372036854775808
# jq .
	9223372036854776000

[stale]

This issue has been automatically marked as "stale" because it has not had any activity for a while. It will be closed in 90 days if no further activity occurs. Thank you for your contributions.

[almereyda]

Tickle stale bot.

…

On Sat, 3 Dec 2022 at 20:08, stale[bot] ***@***.***> wrote: This issue has been automatically marked as "stale" because it has not had any activity for a while. It will be closed in 90 days if no further activity occurs. Thank you for your contributions. — Reply to this email directly, view it on GitHub <#11610 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAMRV7E2INLHIWJKNPR2S2LWLOLBDANCNFSM4XYJFPAQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>