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cem (Conrad Meyer)
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User Since
Jul 9 2015, 9:56 PM (387 w, 14 h)

Recent Activity

Sep 29 2022

cem resigned from D36792: Fix Coverty Scan CID 1498397 - array overrun in kern_sysctl.c.
Sep 29 2022, 8:56 PM
cem requested changes to D36792: Fix Coverty Scan CID 1498397 - array overrun in kern_sysctl.c.

Nevermind

Sep 29 2022, 8:55 PM
cem accepted D36792: Fix Coverty Scan CID 1498397 - array overrun in kern_sysctl.c.
Sep 29 2022, 8:12 PM

Sep 26 2022

cem accepted D36709: geom_part: Fix potential integer overflow when checking size of the table.
Sep 26 2022, 11:55 AM

Sep 23 2022

cem accepted D36679: cpuset(9): Refer to CPU_SETSIZE not MAXCPU.
Sep 23 2022, 7:57 PM

Aug 31 2022

cem accepted D36403: Fix the IV length in the armv8 AES GCM code.

LGTM

Aug 31 2022, 6:15 PM

Aug 9 2022

cem accepted D36088: arc4random(3): Reduce diff with OpenBSD..

As mentioned in email, we might also consider publishing a seed generation to the VDSO page from Fortuna.

Aug 9 2022, 1:29 PM

Jul 13 2022

cem added a comment to D35802: random: Ingest extra fast entropy when !seeded.

Something to keep in mind re: exactly 64 is that it's possible for entropy sources to return less entropy than was requested, if for example some internal state means they don't have anything available at the moment. That's one reason I prefer polling repeatedly until seeded (or some spin threshold is crossed).

Jul 13 2022, 4:25 PM
cem added a comment to D35802: random: Ingest extra fast entropy when !seeded.

Discussed with: cem

Jul 13 2022, 2:49 AM

Jun 6 2022

cem added inline comments to D35411: Add an Armv8 rndr random number provider.
Jun 6 2022, 2:06 PM
cem added inline comments to D35411: Add an Armv8 rndr random number provider.
Jun 6 2022, 1:01 PM
cem accepted D35412: Fix the random source descriptions.
Jun 6 2022, 12:55 PM

May 25 2022

cem accepted D24927: x86/mp: don't create empty cpu groups.

Thanks.

May 25 2022, 8:48 PM

May 24 2022

cem added inline comments to D24927: x86/mp: don't create empty cpu groups.
May 24 2022, 2:50 PM

May 14 2022

cem accepted D35196: dumpon: warn if the configured netdump link is down.

Seems reasonable to me.

May 14 2022, 2:37 AM

May 12 2022

cem accepted D35180: netdump: check the support status of the interface.

Seems very reasonable to me. Thanks!

May 12 2022, 3:54 PM
cem accepted D35179: debugnet: fix an errant assertion.

Seems reasonable to me!

May 12 2022, 3:52 PM

Apr 18 2022

cem accepted D34940: geom: consistently strip /dev/ prefix at input.

LGTM. My only bikeshed contribution is maybe gctl_get_devnameparam or get_devparam. But I don’t object to the current name.

Apr 18 2022, 3:52 PM

Mar 20 2022

cem added inline comments to D33129: bhyve: add ROM emulation.
Mar 20 2022, 6:24 AM · bhyve

Mar 16 2022

cem accepted D34580: xen: fix CPUID signature.
Mar 16 2022, 4:44 PM

Mar 1 2022

cem accepted D34238: zstd: fix benchmarking.

Thanks.

Mar 1 2022, 6:33 PM
cem added reviewers for D34238: zstd: fix benchmarking: bapt, emaste.
Mar 1 2022, 5:57 PM
cem requested changes to D34238: zstd: fix benchmarking.

Setting cstd seems strongly preferable vs making upstream updates more difficult.

Mar 1 2022, 5:57 PM

Feb 28 2022

cem added reviewers for D34393: debugnet: remove spurious message on boot: vangyzen, bdrewery.

Either way seems fine to me. I’d ask vangyzen or bdrewery for input.

Feb 28 2022, 5:04 PM

Feb 11 2022

cem requested changes to D34254: .gitignore: remove .orig/.rej.

What workflow?

Feb 11 2022, 10:53 PM

Feb 9 2022

cem accepted D34220: vt: fix splash_cpu logos use of vd_drawrect.

subtract one from vt_logo_sprite_height as well

Feb 9 2022, 3:00 AM
cem added inline comments to D34221: vt: implement rotation for framebuffer consoles.
Feb 9 2022, 2:46 AM
cem added inline comments to D34220: vt: fix splash_cpu logos use of vd_drawrect.
Feb 9 2022, 2:43 AM

Feb 6 2022

cem added a comment to D34186: tty_info: Avoid warning by using logical instead of bitwise operators.
In D34186#773413, @dim wrote:
In D34186#773402, @cem wrote:

Looks like TESTAB expects boolean (0 and 1) values, too.

Well, the interesting thing is that this macro produces values 0 through 4, and it's a sort of weird shortcut to make the switch(TESTAB()) construct possible.

Feb 6 2022, 7:16 PM
cem accepted D34186: tty_info: Avoid warning by using logical instead of bitwise operators.

Looks like TESTAB expects boolean (0 and 1) values, too.

Feb 6 2022, 6:08 PM

Feb 4 2022

cem accepted D34152: style(9): Default to omitting $FreeBSD$.
Feb 4 2022, 10:32 PM

Feb 3 2022

cem added a comment to D34152: style(9): Default to omitting $FreeBSD$.

@cem: You mean "iff" ? if and only if?

Feb 3 2022, 3:20 PM
cem accepted D34152: style(9): Default to omitting $FreeBSD$.
Feb 3 2022, 2:57 PM
cem accepted D34150: kern: harvest entropy from callouts.
Feb 3 2022, 4:18 AM
cem added a comment to D34150: kern: harvest entropy from callouts.

Looks fine to me. We should probably also actively feed jitter entropy if we hit the blocked state on boot, but that doesn't mean we shouldn't just do this first.

Feb 3 2022, 3:12 AM

Feb 1 2022

cem accepted D32144: fstyp: Remove __packed from struct exfat_de_label..
Feb 1 2022, 1:12 AM

Jan 8 2022

cem accepted D33794: gitignore: ignore vim swap files & .rej/.orig.

Typo in summary: s/path/patch/

Jan 8 2022, 4:57 PM

Jan 3 2022

cem accepted D33686: gdb(4): Do not use run length encoding for 3-symbol repetitions.

Thanks.

Jan 3 2022, 12:18 AM

Dec 29 2021

cem added a comment to D33686: gdb(4): Do not use run length encoding for 3-symbol repetitions.

I’m hoping emaste will be able to test and commit it.

Dec 29 2021, 4:34 PM

Dec 28 2021

cem accepted D33686: gdb(4): Do not use run length encoding for 3-symbol repetitions.

LGTM, thanks.

Dec 28 2021, 10:52 PM

Dec 15 2021

cem accepted D33474: aesni: Fix yet another out-of-bounds read.
Dec 15 2021, 8:03 PM
cem added a comment to D33474: aesni: Fix yet another out-of-bounds read.

LGTM modulo overflow concern and what looks like a typo.

Dec 15 2021, 6:02 PM

Dec 11 2021

cem accepted D33373: Add accelerated arm64 sha512 to libmd.

Lgtm. I didn’t attempt to verify the asm implementation.

Dec 11 2021, 5:40 PM

Nov 29 2021

cem added a comment to D33168: gpart: add options to move the primary and secondary GPT partition tables.

Seems ok in principle.

Nov 29 2021, 11:22 PM
cem added a comment to D32725: entropy: add quick check before taking lock.

At a minimum, you have rdseed (rdrand). But I expect there are other non-ethernet sources present as well.

Nov 29 2021, 3:36 PM

Nov 19 2021

cem added a comment to D32725: entropy: add quick check before taking lock.

The problem is that in some use cases we might not have a lot of entropy good sources, with the ethernet being the only good candidate.

Nov 19 2021, 4:06 PM

Nov 17 2021

cem added a comment to D32725: entropy: add quick check before taking lock.

Consider just disabling Ethernet entropy collection instead. In fact, I thought it was off by default in approximately the 13 timeframe. Maybe even 12.

Nov 17 2021, 2:57 PM

Nov 16 2021

cem accepted D33012: aesni: Avoid a potential out-of-bounds load in AES_GCM_encrypt().

Cool

Nov 16 2021, 4:20 PM
cem accepted D33012: aesni: Avoid a potential out-of-bounds load in AES_GCM_encrypt().
Nov 16 2021, 3:19 PM

Nov 15 2021

cem added inline comments to D32984: randomdev: Remove 100 ms sleep from write routine.
Nov 15 2021, 5:08 PM

Nov 13 2021

cem added inline comments to D32984: randomdev: Remove 100 ms sleep from write routine.
Nov 13 2021, 11:18 PM
cem accepted D32984: randomdev: Remove 100 ms sleep from write routine.

Fortuna doesn't specify the 100ms sleep behavior, as far as I can tell. Removing it seems reasonable to me.

Nov 13 2021, 7:05 PM

Oct 29 2021

cem added a comment to D32725: entropy: add quick check before taking lock.

This change should come with a motivational ministat graph.

Oct 29 2021, 12:41 PM

Oct 25 2021

cem added a comment to D32478: kern: random: use a spinlock for the reseed lock.

I meant fundamentally bad idea. Very little work should happen in interrupt context. Taking a global lock and running AES in software is somewhat expensive.

Oct 25 2021, 5:41 PM

Oct 13 2021

cem added a comment to D32478: kern: random: use a spinlock for the reseed lock.

I don't believe anything should be consuming random in interrupt contexts. Could you elaborate on the scenario / bug?

Oct 13 2021, 8:01 AM

Sep 27 2021

cem added inline comments to D32144: fstyp: Remove __packed from struct exfat_de_label..
Sep 27 2021, 6:32 PM

Sep 25 2021

cem accepted D32144: fstyp: Remove __packed from struct exfat_de_label..

Address of packed member? How?

Sep 25 2021, 6:33 PM

Sep 21 2021

cem added inline comments to D32028: bitset(9): Introduce BIT_FOREACH_SET and BIT_FOREACH_CLR.
Sep 21 2021, 5:44 PM
cem accepted D32021: kern: random: reduce the rate at which we collect from fast entropy sources.

Lgtm, thanks for driving this.

Sep 21 2021, 5:42 PM
cem added a comment to D32021: kern: random: reduce the rate at which we collect from fast entropy sources.

Let’s re-remove read_rate_increment but otherwise it’s looking good to me.

Sep 21 2021, 5:13 PM

Sep 20 2021

cem accepted D32028: bitset(9): Introduce BIT_FOREACH_SET and BIT_FOREACH_CLR.
Sep 20 2021, 10:47 PM
cem accepted D32028: bitset(9): Introduce BIT_FOREACH_SET and BIT_FOREACH_CLR.
Sep 20 2021, 7:28 PM
cem accepted D32029: Convert consumers to use the CPU_FOREACH_SET() macro.
Sep 20 2021, 7:16 PM
cem added inline comments to D32021: kern: random: reduce the rate at which we collect from fast entropy sources.
Sep 20 2021, 9:04 AM

Sep 19 2021

cem added a comment to D32013: virtqueue: add virtqueue_poll_timeout().

OK, I can throw together a patch to this effect. Based on your description here, we're tentatively punting on the idea of just collecting into the zero pool for now, right? My understanding is that 128 bits into the zero pool is the bare minimum and 256 bits per pool per second as a good compromise between there and where we're at now.

Sep 19 2021, 8:49 PM

Sep 18 2021

cem added a comment to D32013: virtqueue: add virtqueue_poll_timeout().

If that's an option, then sure. =-) I didn't/don't understand fortuna's design well enough to make claims about what a reasonable rate is. If we can securely drop it down to <= 1kB/s on average then yeah, we can probably just not care about this at all.

Sep 18 2021, 7:57 PM
cem added a comment to D32013: virtqueue: add virtqueue_poll_timeout().

I hadn’t seen the patch moving the stack buffer to the softc when I wrote my earlier remarks. I still think we should be polling less volume.

Sep 18 2021, 6:25 PM
cem added a comment to D32014: virtio_random: timeout rather than blocking entropy collection.

As mentioned earlier in the stack I don’t think this mitigation is great.

Sep 18 2021, 6:21 PM
cem added a comment to D32013: virtqueue: add virtqueue_poll_timeout().

I don’t think this is a great mitigation for random - the pending request will still be written in guest memory, and we need the queue completion to know when we can free the memory.

Sep 18 2021, 6:14 PM

Aug 30 2021

cem accepted D31730: aesni: Avoid a potential out-of-bounds load in aes_encrypt_icm().

Lgtm.

Aug 30 2021, 5:55 PM

Aug 12 2021

cem added a comment to D31510: arc4random: Avoid KMSAN false positives from pre-seeding results.

LTO builds can see across CUs. I don’t know of any particular pass that would eliminate this, though.

Aug 12 2021, 2:38 PM
cem added a comment to D31510: arc4random: Avoid KMSAN false positives from pre-seeding results.

What exactly is the UB here? I'm not sure how the compiler could legally eliminate SHA256_Update(&ctx, key, sizeof(key)).

Aug 12 2021, 2:15 PM

Aug 11 2021

cem accepted D31510: arc4random: Avoid KMSAN false positives from pre-seeding results.

It's not exactly a false positive, although poisoning the output as uninitialized is sort of unhelpful. Are we confident the compiler isn't eliminating access to it (due to UB) outside of KMSAN? In the abstract, I think we would prefer to eliminate bypass_before_seeding.

Aug 11 2021, 11:05 PM

Aug 6 2021

cem accepted D31284: Use arm64 sha256 intrinsics in libmd.
Aug 6 2021, 4:34 PM

Jul 29 2021

cem closed D31292: libc qsort(3): Eliminate ambiguous sign comparison.
Jul 29 2021, 4:01 AM
cem committed rG7f8f79a5c444: libc qsort(3): Eliminate ambiguous sign comparison (authored by cem).
libc qsort(3): Eliminate ambiguous sign comparison
Jul 29 2021, 4:01 AM

Jul 28 2021

cem updated the diff for D31292: libc qsort(3): Eliminate ambiguous sign comparison.

Oops. Use C89-style comments per style(9).

Jul 28 2021, 10:31 PM
cem updated the diff for D31292: libc qsort(3): Eliminate ambiguous sign comparison.

Add comment explaining the cast.

Jul 28 2021, 5:24 PM
cem added a comment to D31327: debugnet_handle_arp(): Fix false-positive assertion for dp_state.

I don't know exactly but I figured it was simple latency with something like debugnet_arp_gw sending arp request 1, delay(500), retry -> arp request 2 sent, arp reply 1 received (state changes), delay(500), arp reply 2 received (panic due to unexpected state).

Jul 28 2021, 5:13 PM
cem accepted D31327: debugnet_handle_arp(): Fix false-positive assertion for dp_state.

This would only happen if you have multiple competing dhcp servers on a subnet, right? Edit: not dhcp, oops. Still, kind of surprising we’re getting multiple ARP responses?

Jul 28 2021, 3:37 PM

Jul 27 2021

cem accepted D31319: netdump: Fix leaking debugnet state on errors..
Jul 27 2021, 4:35 AM

Jul 24 2021

cem accepted D31300: dumpon: Fix unconfiguring netdump with "off" and "/dev/null"..
Jul 24 2021, 9:58 PM

Jul 23 2021

cem added inline comments to D31292: libc qsort(3): Eliminate ambiguous sign comparison.
Jul 23 2021, 11:38 PM
cem updated the summary of D31292: libc qsort(3): Eliminate ambiguous sign comparison.
Jul 23 2021, 9:26 PM
cem updated the diff for D31292: libc qsort(3): Eliminate ambiguous sign comparison.

Use ssize_t.

Jul 23 2021, 9:24 PM
cem added a comment to D31292: libc qsort(3): Eliminate ambiguous sign comparison.
In D31292#704741, @kib wrote:

ptrdiff_t sounds arbitrary. Why did not you used e.g. ssize_t? Because it is not defined by C STD?

Jul 23 2021, 8:49 PM
cem requested review of D31292: libc qsort(3): Eliminate ambiguous sign comparison.
Jul 23 2021, 7:56 PM
cem added inline comments to D31284: Use arm64 sha256 intrinsics in libmd.
Jul 23 2021, 5:04 PM

May 11 2021

cem added a comment to D30170: sort: Cache value of MB_CUR_MAX.

Is there a way we could make MB_CUR_MAX or __mb_cur_max suck less, in a more general way? Like, isn't it basically always four or one?

May 11 2021, 12:45 AM

May 1 2021

cem added a comment to D26743: Factor out code from fstyp into libfstyp.

I think the idea is very reasonable and could be done in a way that preserves the safety of the sandbox, at least for fstyp. I don't think the popen approach makes sense. There may be a lot of work required to sandbox the suggested consumer (mount).

May 1 2021, 7:03 PM

Apr 12 2021

cem added inline comments to D29736: OCF: Remove support for asymmetric cryptographic operations..
Apr 12 2021, 9:12 PM
cem accepted D29736: OCF: Remove support for asymmetric cryptographic operations..

Nice cleanup. I didn't review the man page language updates super thoroughly, but the parts I skimmed looked good.

Apr 12 2021, 9:11 PM

Apr 1 2021

cem accepted D29518: cryptocheck: Expand the set of sizes tested by -z..

Merci

Apr 1 2021, 10:16 PM

Mar 31 2021

cem edited P491 'pciconf -lc pci0:0:0:2' ryzen 5800x.
Mar 31 2021, 10:43 PM
cem added inline comments to D29518: cryptocheck: Expand the set of sizes tested by -z..
Mar 31 2021, 10:30 PM
cem accepted D29517: ossl: Don't encryt/decrypt too much data for chacha20..
Mar 31 2021, 6:09 PM
cem added inline comments to D29518: cryptocheck: Expand the set of sizes tested by -z..
Mar 31 2021, 6:07 PM

Mar 23 2021

cem accepted D29385: Make random() behaves as documented: "result is uniform in [0, 2^31 - 1]".

Thanks!

Mar 23 2021, 5:05 PM
cem accepted D29385: Make random() behaves as documented: "result is uniform in [0, 2^31 - 1]".

Nice find. I'd encourage using prng32_bounded instead, but I don't think this is mechanically wrong.

Mar 23 2021, 5:52 AM

Mar 16 2021

cem accepted D29173: gdb: allow setting/removing hardware watchpoints.

Awesome, thanks!

Mar 16 2021, 4:25 PM