| Message ID | 20221008055359.286426-1-Jason@zx2c4.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | treewide cleanup of random integer usage | expand |
On Fri, Oct 07, 2022 at 11:53:52PM -0600, Jason A. Donenfeld wrote: > Changes v4->v5: > - Coccinelle is now used for as much mechanical aspects as possible, > with mechanical parts split off from non-mechanical parts. This should > drastically reduce the amount of code that needs to be reviewed > carefully. Each commit mentions now if it was done by hand or is > mechanical. All look good to me, thanks for the cleanups. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On Fri, Oct 07, 2022 at 11:53:52PM -0600, Jason A. Donenfeld wrote: > Changes v4->v5: > - Coccinelle is now used for as much mechanical aspects as possible, > with mechanical parts split off from non-mechanical parts. This should > drastically reduce the amount of code that needs to be reviewed > carefully. Each commit mentions now if it was done by hand or is > mechanical. > > 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(). Same for > get_random_int(). > - 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: > > 1) Replace `prandom_u32() % max` and variants thereof with > prandom_u32_max(max). > > * Part 1 is done with Coccinelle. Part 2 is done by hand. > > 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. > > * Part 1 is done with Coccinelle. Part 2 is done by hand. > > 3) Replace remaining deprecated uses of prandom_u32() and > get_random_int() with get_random_u32(). > > * A boring search and replace operation. > > 4) Replace remaining deprecated uses of prandom_bytes() with > get_random_bytes(). > > * A boring search and replace operation. > > 5) Remove the deprecated and now-unused prandom_u32() and > prandom_bytes() inline wrapper functions. > > * Just deleting code and updating comments. > > 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! The number of lines touched is quite small, so this > should be reviewable, and as much as is possible has been pushed into > Coccinelle scripts. For the series: Reviewed-by: Yury Norov <yury.norov@gmail.com> Although, looking at it, I have a feeling that kernel needs to drop all fixed-size random APIs like get_random_uXX() or get_random_int(), because people will continue using the 'get_random_int() % num' carelessly. Thanks, Yury
On Fri, Oct 07, 2022 at 11:53:52PM -0600, Jason A. Donenfeld wrote: > This is a five part treewide cleanup of random integer handling. The > rules for random integers are: Reviewing the delta between of my .cocci rules and your v5, everything matches, except for get_random_int() conversions for files not in your tree: diff --git a/drivers/gpu/drm/tests/drm_buddy_test.c b/drivers/gpu/drm/tests/drm_buddy_test.c index 7a2b2d6bc3fe..62f69589a72d 100644 --- a/drivers/gpu/drm/tests/drm_buddy_test.c +++ b/drivers/gpu/drm/tests/drm_buddy_test.c @@ -729,7 +729,7 @@ static void drm_test_buddy_alloc_limit(struct kunit *test) static int drm_buddy_init_test(struct kunit *test) { while (!random_seed) - random_seed = get_random_int(); + random_seed = get_random_u32(); return 0; } diff --git a/drivers/gpu/drm/tests/drm_mm_test.c b/drivers/gpu/drm/tests/drm_mm_test.c index 659d1af4dca7..c4b66eeae203 100644 --- a/drivers/gpu/drm/tests/drm_mm_test.c +++ b/drivers/gpu/drm/tests/drm_mm_test.c @@ -2212,7 +2212,7 @@ static void drm_test_mm_color_evict_range(struct kunit *test) static int drm_mm_init_test(struct kunit *test) { while (!random_seed) - random_seed = get_random_int(); + random_seed = get_random_u32(); return 0; } So, I guess I mean to say that "prandom: remove unused functions" is going to cause some pain. :) Perhaps don't push that to -next, and do a final pass next merge window to catch any new stuff, and then send those updates and the removal before -rc1 closes?
On Sat, Oct 08, 2022 at 08:41:14PM -0700, Kees Cook wrote: > On Fri, Oct 07, 2022 at 11:53:52PM -0600, Jason A. Donenfeld wrote: > > This is a five part treewide cleanup of random integer handling. The > > rules for random integers are: > > Reviewing the delta between of my .cocci rules and your v5, everything > matches, except for get_random_int() conversions for files not in > your tree: > [...] > So, I guess I mean to say that "prandom: remove unused functions" is > going to cause some pain. :) Perhaps don't push that to -next, and do a > final pass next merge window to catch any new stuff, and then send those > updates and the removal before -rc1 closes? Ooof. Actually I think what I'll do is include a suggested diff for the merge commit that fixes up the remaining two thankfully trivial cases. Jason
Changes v4->v5: - Coccinelle is now used for as much mechanical aspects as possible, with mechanical parts split off from non-mechanical parts. This should drastically reduce the amount of code that needs to be reviewed carefully. Each commit mentions now if it was done by hand or is mechanical. 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(). Same for get_random_int(). - 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: 1) Replace `prandom_u32() % max` and variants thereof with prandom_u32_max(max). * Part 1 is done with Coccinelle. Part 2 is done by hand. 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. * Part 1 is done with Coccinelle. Part 2 is done by hand. 3) Replace remaining deprecated uses of prandom_u32() and get_random_int() with get_random_u32(). * A boring search and replace operation. 4) Replace remaining deprecated uses of prandom_bytes() with get_random_bytes(). * A boring search and replace operation. 5) Remove the deprecated and now-unused prandom_u32() and prandom_bytes() inline wrapper functions. * Just deleting code and updating comments. 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! The number of lines touched is quite small, so this should be reviewable, and as much as is possible has been pushed into Coccinelle scripts. Thanks, Jason Cc: Andreas Noever <andreas.noever@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Dave Airlie <airlied@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Florian Westphal <fw@strlen.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Cc: H. Peter Anvin <hpa@zytor.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Jan Kara <jack@suse.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jozsef Kadlecsik <kadlec@netfilter.org> Cc: KP Singh <kpsingh@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Graf <tgraf@suug.ch> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Vignesh Raghavendra <vigneshr@ti.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: dri-devel@lists.freedesktop.org Cc: kasan-dev@googlegroups.com Cc: kernel-janitors@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-block@vger.kernel.org Cc: linux-crypto@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-mmc@vger.kernel.org Cc: linux-mtd@lists.infradead.org Cc: linux-nvme@lists.infradead.org Cc: linux-parisc@vger.kernel.org Cc: linux-rdma@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-um@lists.infradead.org Cc: linux-usb@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: loongarch@lists.linux.dev Cc: netdev@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: x86@kernel.org Jason A. Donenfeld (7): treewide: use prandom_u32_max() when possible, part 1 treewide: use prandom_u32_max() when possible, part 2 treewide: use get_random_{u8,u16}() when possible, part 1 treewide: use get_random_{u8,u16}() when possible, part 2 treewide: use get_random_u32() when possible treewide: use get_random_bytes when possible prandom: remove unused functions Documentation/networking/filter.rst | 2 +- arch/arm/kernel/process.c | 2 +- arch/arm/kernel/signal.c | 2 +- arch/arm64/kernel/process.c | 2 +- arch/arm64/kernel/syscall.c | 2 +- arch/loongarch/kernel/process.c | 2 +- arch/loongarch/kernel/vdso.c | 2 +- arch/mips/kernel/process.c | 2 +- arch/mips/kernel/vdso.c | 2 +- arch/parisc/kernel/process.c | 2 +- arch/parisc/kernel/sys_parisc.c | 4 +- arch/parisc/kernel/vdso.c | 2 +- arch/powerpc/crypto/crc-vpmsum_test.c | 2 +- arch/powerpc/kernel/process.c | 2 +- arch/s390/kernel/process.c | 4 +- arch/s390/kernel/vdso.c | 2 +- arch/s390/mm/mmap.c | 2 +- arch/sparc/vdso/vma.c | 2 +- arch/um/kernel/process.c | 2 +- arch/x86/entry/vdso/vma.c | 2 +- arch/x86/kernel/cpu/amd.c | 2 +- arch/x86/kernel/module.c | 2 +- arch/x86/kernel/process.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/char/random.c | 11 +-- drivers/dma/dmatest.c | 2 +- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +- drivers/gpu/drm/i915/i915_gem_gtt.c | 6 +- .../gpu/drm/i915/selftests/i915_selftest.c | 2 +- drivers/gpu/drm/selftests/test-drm_buddy.c | 2 +- drivers/gpu/drm/selftests/test-drm_mm.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/bcache/request.c | 2 +- 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 +- .../test-drivers/vivid/vivid-touch-cap.c | 6 +- drivers/misc/habanalabs/gaudi2/gaudi2.c | 2 +- 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 +- .../broadcom/brcm80211/brcmfmac/pno.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/net/wireless/st/cw1200/wsm.c | 2 +- drivers/net/wireless/ti/wlcore/main.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/ntfs3/fslog.c | 6 +- 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/nodemask.h | 2 +- include/linux/prandom.h | 12 --- include/linux/random.h | 5 - include/net/netfilter/nf_queue.h | 2 +- include/net/red.h | 2 +- include/net/sock.h | 2 +- kernel/bpf/bloom_filter.c | 2 +- kernel/bpf/core.c | 6 +- kernel/bpf/hashtab.c | 2 +- kernel/bpf/verifier.c | 2 +- kernel/kcsan/selftest.c | 4 +- kernel/locking/test-ww_mutex.c | 4 +- kernel/time/clocksource.c | 2 +- lib/cmdline_kunit.c | 4 +- lib/fault-inject.c | 2 +- lib/find_bit_benchmark.c | 4 +- lib/kobject.c | 2 +- lib/random32.c | 4 +- lib/reed_solomon/test_rslib.c | 12 +-- lib/sbitmap.c | 4 +- lib/test-string_helpers.c | 2 +- lib/test_fprobe.c | 2 +- lib/test_hexdump.c | 10 +- lib/test_kasan.c | 6 +- lib/test_kprobes.c | 2 +- lib/test_list_sort.c | 2 +- lib/test_min_heap.c | 6 +- lib/test_objagg.c | 2 +- lib/test_rhashtable.c | 6 +- lib/test_vmalloc.c | 19 +--- lib/uuid.c | 2 +- mm/migrate.c | 2 +- mm/shmem.c | 2 +- mm/slab.c | 2 +- mm/slub.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 | 4 +- 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 +- 186 files changed, 379 insertions(+), 422 deletions(-)