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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 16:22:22 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-12 16:22:22 -0800 |
commit | 268325bda5299836a6ad4c3952474a2be125da5f (patch) | |
tree | 5f7b22109b7a21d0aab68cab8de0ee201426aae1 /net/ipv6 | |
parent | ca1443c7e75a28c6fde5c67cb1904b624cf43c36 (diff) | |
parent | 3e6743e28b9b43d37ced234bdf8e19955d0216f8 (diff) |
Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
- Replace prandom_u32_max() and various open-coded variants of it,
there is now a new family of functions that uses fast rejection
sampling to choose properly uniformly random numbers within an
interval:
get_random_u32_below(ceil) - [0, ceil)
get_random_u32_above(floor) - (floor, U32_MAX]
get_random_u32_inclusive(floor, ceil) - [floor, ceil]
Coccinelle was used to convert all current users of
prandom_u32_max(), as well as many open-coded patterns, resulting in
improvements throughout the tree.
I'll have a "late" 6.1-rc1 pull for you that removes the now unused
prandom_u32_max() function, just in case any other trees add a new
use case of it that needs to converted. According to linux-next,
there may be two trivial cases of prandom_u32_max() reintroductions
that are fixable with a 's/.../.../'. So I'll have for you a final
conversion patch doing that alongside the removal patch during the
second week.
This is a treewide change that touches many files throughout.
- More consistent use of get_random_canary().
- Updates to comments, documentation, tests, headers, and
simplification in configuration.
- The arch_get_random*_early() abstraction was only used by arm64 and
wasn't entirely useful, so this has been replaced by code that works
in all relevant contexts.
- The kernel will use and manage random seeds in non-volatile EFI
variables, refreshing a variable with a fresh seed when the RNG is
initialized. The RNG GUID namespace is then hidden from efivarfs to
prevent accidental leakage.
These changes are split into random.c infrastructure code used in the
EFI subsystem, in this pull request, and related support inside of
EFISTUB, in Ard's EFI tree. These are co-dependent for full
functionality, but the order of merging doesn't matter.
- Part of the infrastructure added for the EFI support is also used for
an improvement to the way vsprintf initializes its siphash key,
replacing an sleep loop wart.
- The hardware RNG framework now always calls its correct random.c
input function, add_hwgenerator_randomness(), rather than sometimes
going through helpers better suited for other cases.
- The add_latent_entropy() function has long been called from the fork
handler, but is a no-op when the latent entropy gcc plugin isn't
used, which is fine for the purposes of latent entropy.
But it was missing out on the cycle counter that was also being mixed
in beside the latent entropy variable. So now, if the latent entropy
gcc plugin isn't enabled, add_latent_entropy() will expand to a call
to add_device_randomness(NULL, 0), which adds a cycle counter,
without the absent latent entropy variable.
- The RNG is now reseeded from a delayed worker, rather than on demand
when used. Always running from a worker allows it to make use of the
CPU RNG on platforms like S390x, whose instructions are too slow to
do so from interrupts. It also has the effect of adding in new inputs
more frequently with more regularity, amounting to a long term
transcript of random values. Plus, it helps a bit with the upcoming
vDSO implementation (which isn't yet ready for 6.2).
- The jitter entropy algorithm now tries to execute on many different
CPUs, round-robining, in hopes of hitting even more memory latencies
and other unpredictable effects. It also will mix in a cycle counter
when the entropy timer fires, in addition to being mixed in from the
main loop, to account more explicitly for fluctuations in that timer
firing. And the state it touches is now kept within the same cache
line, so that it's assured that the different execution contexts will
cause latencies.
* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits)
random: include <linux/once.h> in the right header
random: align entropy_timer_state to cache line
random: mix in cycle counter when jitter timer fires
random: spread out jitter callback to different CPUs
random: remove extraneous period and add a missing one in comments
efi: random: refresh non-volatile random seed when RNG is initialized
vsprintf: initialize siphash key using notifier
random: add back async readiness notifier
random: reseed in delayed work rather than on-demand
random: always mix cycle counter in add_latent_entropy()
hw_random: use add_hwgenerator_randomness() for early entropy
random: modernize documentation comment on get_random_bytes()
random: adjust comment to account for removed function
random: remove early archrandom abstraction
random: use random.trust_{bootloader,cpu} command line option only
stackprotector: actually use get_random_canary()
stackprotector: move get_random_canary() into stackprotector.h
treewide: use get_random_u32_inclusive() when possible
treewide: use get_random_u32_{above,below}() instead of manual loop
treewide: use get_random_u32_below() instead of deprecated function
...
Diffstat (limited to 'net/ipv6')
-rw-r--r-- | net/ipv6/addrconf.c | 8 | ||||
-rw-r--r-- | net/ipv6/mcast.c | 10 | ||||
-rw-r--r-- | net/ipv6/output_core.c | 8 | ||||
-rw-r--r-- | net/ipv6/route.c | 2 |
4 files changed, 11 insertions, 17 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 9c3f5202a97b..d720f6f5de3f 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -104,7 +104,7 @@ static inline u32 cstamp_delta(unsigned long cstamp) static inline s32 rfc3315_s14_backoff_init(s32 irt) { /* multiply 'initial retransmission time' by 0.9 .. 1.1 */ - u64 tmp = (900000 + prandom_u32_max(200001)) * (u64)irt; + u64 tmp = get_random_u32_inclusive(900000, 1100000) * (u64)irt; do_div(tmp, 1000000); return (s32)tmp; } @@ -112,11 +112,11 @@ static inline s32 rfc3315_s14_backoff_init(s32 irt) static inline s32 rfc3315_s14_backoff_update(s32 rt, s32 mrt) { /* multiply 'retransmission timeout' by 1.9 .. 2.1 */ - u64 tmp = (1900000 + prandom_u32_max(200001)) * (u64)rt; + u64 tmp = get_random_u32_inclusive(1900000, 2100000) * (u64)rt; do_div(tmp, 1000000); if ((s32)tmp > mrt) { /* multiply 'maximum retransmission time' by 0.9 .. 1.1 */ - tmp = (900000 + prandom_u32_max(200001)) * (u64)mrt; + tmp = get_random_u32_inclusive(900000, 1100000) * (u64)mrt; do_div(tmp, 1000000); } return (s32)tmp; @@ -3967,7 +3967,7 @@ static void addrconf_dad_kick(struct inet6_ifaddr *ifp) if (ifp->flags & IFA_F_OPTIMISTIC) rand_num = 0; else - rand_num = prandom_u32_max(idev->cnf.rtr_solicit_delay ?: 1); + rand_num = get_random_u32_below(idev->cnf.rtr_solicit_delay ? : 1); nonce = 0; if (idev->cnf.enhanced_dad || diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 7860383295d8..1c02160cf7a4 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1050,7 +1050,7 @@ bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group, /* called with mc_lock */ static void mld_gq_start_work(struct inet6_dev *idev) { - unsigned long tv = prandom_u32_max(idev->mc_maxdelay); + unsigned long tv = get_random_u32_below(idev->mc_maxdelay); idev->mc_gq_running = 1; if (!mod_delayed_work(mld_wq, &idev->mc_gq_work, tv + 2)) @@ -1068,7 +1068,7 @@ static void mld_gq_stop_work(struct inet6_dev *idev) /* called with mc_lock */ static void mld_ifc_start_work(struct inet6_dev *idev, unsigned long delay) { - unsigned long tv = prandom_u32_max(delay); + unsigned long tv = get_random_u32_below(delay); if (!mod_delayed_work(mld_wq, &idev->mc_ifc_work, tv + 2)) in6_dev_hold(idev); @@ -1085,7 +1085,7 @@ static void mld_ifc_stop_work(struct inet6_dev *idev) /* called with mc_lock */ static void mld_dad_start_work(struct inet6_dev *idev, unsigned long delay) { - unsigned long tv = prandom_u32_max(delay); + unsigned long tv = get_random_u32_below(delay); if (!mod_delayed_work(mld_wq, &idev->mc_dad_work, tv + 2)) in6_dev_hold(idev); @@ -1130,7 +1130,7 @@ static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime) } if (delay >= resptime) - delay = prandom_u32_max(resptime); + delay = get_random_u32_below(resptime); if (!mod_delayed_work(mld_wq, &ma->mca_work, delay)) refcount_inc(&ma->mca_refcnt); @@ -2574,7 +2574,7 @@ static void igmp6_join_group(struct ifmcaddr6 *ma) igmp6_send(&ma->mca_addr, ma->idev->dev, ICMPV6_MGM_REPORT); - delay = prandom_u32_max(unsolicited_report_interval(ma->idev)); + delay = get_random_u32_below(unsolicited_report_interval(ma->idev)); if (cancel_delayed_work(&ma->mca_work)) { refcount_dec(&ma->mca_refcnt); diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c index 2685c3f15e9d..b5205311f372 100644 --- a/net/ipv6/output_core.c +++ b/net/ipv6/output_core.c @@ -15,13 +15,7 @@ static u32 __ipv6_select_ident(struct net *net, const struct in6_addr *dst, const struct in6_addr *src) { - u32 id; - - do { - id = get_random_u32(); - } while (!id); - - return id; + return get_random_u32_above(0); } /* This function exists only for tap drivers that must support broken diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 2f355f0ec32a..e74e0361fd92 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1713,7 +1713,7 @@ static int rt6_insert_exception(struct rt6_info *nrt, net->ipv6.rt6_stats->fib_rt_cache++; /* Randomize max depth to avoid some side channels attacks. */ - max_depth = FIB6_MAX_DEPTH + prandom_u32_max(FIB6_MAX_DEPTH); + max_depth = FIB6_MAX_DEPTH + get_random_u32_below(FIB6_MAX_DEPTH); while (bucket->depth > max_depth) rt6_exception_remove_oldest(bucket); |