[PATCH v2 0/5] treewide cleanup of random integer usage
Jason A. Donenfeld
Jason at zx2c4.com
Thu Oct 6 06:25:05 PDT 2022
[Posting v2 right away, because I CC'd too many people for v1, and email
systems worldwide exploded.]
Hi folks,
This is a five part treewide cleanup of random integer handling. The
rules for random integers are:
- If you want a secure or an insecure random u64, use get_random_u64().
- If you want a secure or an insecure random u32, use get_random_u32().
* The old function prandom_u32() has been deprecated for a while now
and is just a wrapper around get_random_u32().
- If you want a secure or an insecure random u16, use get_random_u16().
- If you want a secure or an insecure random u8, use get_random_u8().
- If you want secure or insecure random bytes, use get_random_bytes().
* The old function prandom_bytes() has been deprecated for a while now
and has long been a wrapper around get_random_bytes().
- If you want a non-uniform random u32, u16, or u8 bounded by a certain
open interval maximum, use prandom_u32_max().
* I say "non-uniform", because it doesn't do any rejection sampling or
divisions. Hence, it stays within the prandom_* namespace.
These rules ought to be applied uniformly, so that we can clean up the
deprecated functions, and earn the benefits of using the modern
functions. In particular, in addition to the boring substitutions, this
patchset accomplishes a few nice effects:
- By using prandom_u32_max() with an upper-bound that the compiler can
prove at compile-time is ≤65536 or ≤256, internally get_random_u16()
or get_random_u8() is used, which wastes fewer batched random bytes,
and hence has higher throughput.
- By using prandom_u32_max() instead of %, when the upper-bound is not a
constant, division is still avoided, because prandom_u32_max() uses
a faster multiplication-based trick instead.
- By using get_random_u16() or get_random_u8() in cases where the return
value is intended to indeed be a u16 or a u8, we waste fewer batched
random bytes, and hence have higher throughput.
So, based on those rules and benefits from following them, this patchset
breaks down into the following five steps, which were done mostly
manually:
1) Replace `prandom_u32() % max` and variants thereof with
prandom_u32_max(max).
2) Replace `(type)get_random_u32()` and variants thereof with
get_random_u16() or get_random_u8(). I took the pains to actually
look and see what every lvalue type was across the entire tree.
3) Replace remaining deprecated uses of prandom_u32() with
get_random_u32().
4) Replace remaining deprecated uses of prandom_bytes() with
get_random_bytes().
5) Remove the deprecated and now-unused prandom_u32() and
prandom_bytes() inline wrapper functions.
I was thinking of taking this through my random.git tree (on which this
series is currently based) and submitting it near the end of the merge
window, or waiting for the very end of the 6.1 cycle when there will be
the fewest new patches brewing. If somebody with some treewide-cleanup
experience might share some wisdom about what the best timing usually
winds up being, I'm all ears.
Please take a look!
Thanks,
Jason
Cc: Andreas Noever <andreas.noever at gmail.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Cc: Borislav Petkov <bp at alien8.de>
Cc: Christoph Böhmwalder <christoph.boehmwalder at linbit.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Daniel Borkmann <daniel at iogearbox.net>
Cc: Dave Airlie <airlied at redhat.com>
Cc: Dave Hansen <dave.hansen at linux.intel.com>
Cc: David S. Miller <davem at davemloft.net>
Cc: Eric Dumazet <edumazet at google.com>
Cc: Florian Westphal <fw at strlen.de>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>,
Cc: H. Peter Anvin <hpa at zytor.com>
Cc: Herbert Xu <herbert at gondor.apana.org.au>
Cc: Hugh Dickins <hughd at google.com>
Cc: Jakub Kicinski <kuba at kernel.org>
Cc: James E.J. Bottomley <jejb at linux.ibm.com>
Cc: Jan Kara <jack at suse.com>
Cc: Jason Gunthorpe <jgg at ziepe.ca>
Cc: Jens Axboe <axboe at kernel.dk>
Cc: Johannes Berg <johannes at sipsolutions.net>
Cc: Jonathan Corbet <corbet at lwn.net>
Cc: Jozsef Kadlecsik <kadlec at netfilter.org>
Cc: KP Singh <kpsingh at kernel.org>
Cc: Kees Cook <keescook at chromium.org>
Cc: Marco Elver <elver at google.com>
Cc: Mauro Carvalho Chehab <mchehab at kernel.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Pablo Neira Ayuso <pablo at netfilter.org>
Cc: Paolo Abeni <pabeni at redhat.com>
Cc: Theodore Ts'o <tytso at mit.edu>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Thomas Graf <tgraf at suug.ch>
Cc: Ulf Hansson <ulf.hansson at linaro.org>
Cc: Vignesh Raghavendra <vigneshr at ti.com>
Cc: Yury Norov <yury.norov at gmail.com>
Cc: dri-devel at lists.freedesktop.org
Cc: kasan-dev at googlegroups.com
Cc: kernel-janitors at vger.kernel.org
Cc: linux-block at vger.kernel.org
Cc: linux-crypto at vger.kernel.org
Cc: linux-doc at vger.kernel.org
Cc: linux-fsdevel at vger.kernel.org
Cc: linux-media at vger.kernel.org
Cc: linux-mm at kvack.org
Cc: linux-mmc at vger.kernel.org
Cc: linux-mtd at lists.infradead.org
Cc: linux-nvme at lists.infradead.org
Cc: linux-rdma at vger.kernel.org
Cc: linux-usb at vger.kernel.org
Cc: linux-wireless at vger.kernel.org
Cc: netdev at vger.kernel.org
Jason A. Donenfeld (5):
treewide: use prandom_u32_max() when possible
treewide: use get_random_{u8,u16}() when possible
treewide: use get_random_u32() when possible
treewide: use get_random_bytes when possible
prandom: remove unused functions
Documentation/networking/filter.rst | 2 +-
arch/powerpc/crypto/crc-vpmsum_test.c | 2 +-
arch/x86/mm/pat/cpa-test.c | 4 +-
block/blk-crypto-fallback.c | 2 +-
crypto/async_tx/raid6test.c | 2 +-
crypto/testmgr.c | 94 +++++++++----------
drivers/block/drbd/drbd_receiver.c | 4 +-
drivers/dma/dmatest.c | 2 +-
drivers/infiniband/core/cma.c | 2 +-
drivers/infiniband/hw/cxgb4/cm.c | 4 +-
drivers/infiniband/hw/cxgb4/id_table.c | 4 +-
drivers/infiniband/hw/hfi1/tid_rdma.c | 2 +-
drivers/infiniband/hw/hns/hns_roce_ah.c | 5 +-
drivers/infiniband/hw/mlx4/mad.c | 2 +-
drivers/infiniband/ulp/ipoib/ipoib_cm.c | 2 +-
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3 +-
drivers/md/raid5-cache.c | 2 +-
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 2 +-
.../media/test-drivers/vivid/vivid-radio-rx.c | 4 +-
drivers/mmc/core/core.c | 4 +-
drivers/mmc/host/dw_mmc.c | 2 +-
drivers/mtd/nand/raw/nandsim.c | 8 +-
drivers/mtd/tests/mtd_nandecctest.c | 12 +--
drivers/mtd/tests/speedtest.c | 2 +-
drivers/mtd/tests/stresstest.c | 19 +---
drivers/mtd/ubi/debug.c | 2 +-
drivers/mtd/ubi/debug.h | 6 +-
drivers/net/bonding/bond_main.c | 2 +-
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +-
drivers/net/ethernet/broadcom/cnic.c | 5 +-
.../chelsio/inline_crypto/chtls/chtls_cm.c | 4 +-
.../chelsio/inline_crypto/chtls/chtls_io.c | 4 +-
drivers/net/ethernet/rocker/rocker_main.c | 8 +-
drivers/net/hamradio/baycom_epp.c | 2 +-
drivers/net/hamradio/hdlcdrv.c | 2 +-
drivers/net/hamradio/yam.c | 2 +-
drivers/net/phy/at803x.c | 2 +-
drivers/net/wireguard/selftest/allowedips.c | 16 ++--
.../broadcom/brcm80211/brcmfmac/p2p.c | 2 +-
.../net/wireless/intel/iwlwifi/mvm/mac-ctxt.c | 2 +-
.../net/wireless/marvell/mwifiex/cfg80211.c | 4 +-
.../wireless/microchip/wilc1000/cfg80211.c | 2 +-
.../net/wireless/quantenna/qtnfmac/cfg80211.c | 2 +-
drivers/nvme/common/auth.c | 2 +-
drivers/scsi/cxgbi/cxgb4i/cxgb4i.c | 4 +-
drivers/scsi/fcoe/fcoe_ctlr.c | 4 +-
drivers/scsi/lpfc/lpfc_hbadisc.c | 6 +-
drivers/scsi/qedi/qedi_main.c | 2 +-
drivers/target/iscsi/cxgbit/cxgbit_cm.c | 2 +-
drivers/thunderbolt/xdomain.c | 2 +-
drivers/video/fbdev/uvesafb.c | 2 +-
fs/ceph/inode.c | 2 +-
fs/ceph/mdsmap.c | 2 +-
fs/exfat/inode.c | 2 +-
fs/ext2/ialloc.c | 3 +-
fs/ext4/ialloc.c | 7 +-
fs/ext4/ioctl.c | 4 +-
fs/ext4/mmp.c | 2 +-
fs/ext4/super.c | 7 +-
fs/f2fs/gc.c | 2 +-
fs/f2fs/namei.c | 2 +-
fs/f2fs/segment.c | 8 +-
fs/fat/inode.c | 2 +-
fs/nfsd/nfs4state.c | 4 +-
fs/ubifs/debug.c | 10 +-
fs/ubifs/journal.c | 2 +-
fs/ubifs/lpt_commit.c | 14 +--
fs/ubifs/tnc_commit.c | 2 +-
fs/xfs/libxfs/xfs_alloc.c | 2 +-
fs/xfs/libxfs/xfs_ialloc.c | 4 +-
fs/xfs/xfs_error.c | 2 +-
fs/xfs/xfs_icache.c | 2 +-
fs/xfs/xfs_log.c | 2 +-
include/linux/prandom.h | 12 ---
include/net/netfilter/nf_queue.h | 2 +-
include/net/red.h | 2 +-
include/net/sock.h | 2 +-
kernel/kcsan/selftest.c | 4 +-
kernel/time/clocksource.c | 2 +-
lib/fault-inject.c | 2 +-
lib/find_bit_benchmark.c | 4 +-
lib/random32.c | 4 +-
lib/reed_solomon/test_rslib.c | 12 +--
lib/sbitmap.c | 4 +-
lib/test_fprobe.c | 2 +-
lib/test_kprobes.c | 2 +-
lib/test_list_sort.c | 2 +-
lib/test_objagg.c | 2 +-
lib/test_rhashtable.c | 6 +-
lib/test_vmalloc.c | 19 +---
lib/uuid.c | 2 +-
mm/shmem.c | 2 +-
net/802/garp.c | 2 +-
net/802/mrp.c | 2 +-
net/ceph/mon_client.c | 2 +-
net/ceph/osd_client.c | 2 +-
net/core/neighbour.c | 2 +-
net/core/pktgen.c | 47 +++++-----
net/core/stream.c | 2 +-
net/dccp/ipv4.c | 4 +-
net/ipv4/datagram.c | 2 +-
net/ipv4/igmp.c | 6 +-
net/ipv4/inet_connection_sock.c | 2 +-
net/ipv4/inet_hashtables.c | 2 +-
net/ipv4/ip_output.c | 2 +-
net/ipv4/route.c | 2 +-
net/ipv4/tcp_cdg.c | 2 +-
net/ipv4/tcp_ipv4.c | 4 +-
net/ipv4/udp.c | 2 +-
net/ipv6/addrconf.c | 8 +-
net/ipv6/ip6_flowlabel.c | 2 +-
net/ipv6/mcast.c | 10 +-
net/ipv6/output_core.c | 2 +-
net/mac80211/rc80211_minstrel_ht.c | 2 +-
net/mac80211/scan.c | 2 +-
net/netfilter/ipvs/ip_vs_conn.c | 2 +-
net/netfilter/ipvs/ip_vs_twos.c | 4 +-
net/netfilter/nf_nat_core.c | 4 +-
net/netfilter/xt_statistic.c | 2 +-
net/openvswitch/actions.c | 2 +-
net/packet/af_packet.c | 2 +-
net/rds/bind.c | 2 +-
net/sched/act_gact.c | 2 +-
net/sched/act_sample.c | 2 +-
net/sched/sch_cake.c | 8 +-
net/sched/sch_netem.c | 22 ++---
net/sched/sch_pie.c | 2 +-
net/sched/sch_sfb.c | 2 +-
net/sctp/socket.c | 4 +-
net/sunrpc/auth_gss/gss_krb5_wrap.c | 4 +-
net/sunrpc/cache.c | 2 +-
net/sunrpc/xprt.c | 2 +-
net/sunrpc/xprtsock.c | 2 +-
net/tipc/socket.c | 2 +-
net/unix/af_unix.c | 2 +-
net/xfrm/xfrm_state.c | 2 +-
136 files changed, 305 insertions(+), 342 deletions(-)
--
2.37.3
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