Commit 9b6f7e163c ("mm: rework memcg kernel stack accounting") will
result in fork failing if allocating a kernel stack for a task in
dup_task_struct exceeds the kernel memory allowance for that cgroup.
Unfortunately, it also results in a crash.
This is due to the code jumping to free_stack and calling
free_thread_stack when the memcg kernel stack charge fails, but without
tsk->stack pointing at the freshly allocated stack.
This in turn results in the vfree_atomic in free_thread_stack oopsing
with a backtrace like this:
#5 [ffffc900244efc88] die at ffffffff8101f0ab
#6 [ffffc900244efcb8] do_general_protection at ffffffff8101cb86
#7 [ffffc900244efce0] general_protection at ffffffff818ff082
[exception RIP: llist_add_batch+7]
RIP: ffffffff8150d487 RSP: ffffc900244efd98 RFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88085ef55980 RCX: 0000000000000000
RDX: ffff88085ef55980 RSI: 343834343531203a RDI: 343834343531203a
RBP: ffffc900244efd98 R8: 0000000000000001 R9: ffff8808578c3600
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88029f6c21c0
R13: 0000000000000286 R14: ffff880147759b00 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#8 [ffffc900244efda0] vfree_atomic at ffffffff811df2c7
#9 [ffffc900244efdb8] copy_process at ffffffff81086e37
#10 [ffffc900244efe98] _do_fork at ffffffff810884e0
#11 [ffffc900244eff10] sys_vfork at ffffffff810887ff
#12 [ffffc900244eff20] do_syscall_64 at ffffffff81002a43
RIP: 000000000049b948 RSP: 00007ffcdb307830 RFLAGS: 00000246
RAX: ffffffffffffffda RBX: 0000000000896030 RCX: 000000000049b948
RDX: 0000000000000000 RSI: 00007ffcdb307790 RDI: 00000000005d7421
RBP: 000000000067370f R8: 00007ffcdb3077b0 R9: 000000000001ed00
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000040
R13: 000000000000000f R14: 0000000000000000 R15: 000000000088d018
ORIG_RAX: 000000000000003a CS: 0033 SS: 002b
The simplest fix is to assign tsk->stack right where it is allocated.
Link: http://lkml.kernel.org/r/20181214231726.7ee4843c@imladris.surriel.com
Fixes: 9b6f7e163c ("mm: rework memcg kernel stack accounting")
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull timer fix from Ingo Molnar:
"Fix a division by zero crash in the posix-timers code"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
posix-timers: Fix division by zero bug
Pull futex fix from Ingo Molnar:
"A single fix for a robust futexes race between sys_exit() and
sys_futex_lock_pi()"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Cure exit race
Pull networking fixes from David Miller:
1) Off by one in netlink parsing of mac802154_hwsim, from Alexander
Aring.
2) nf_tables RCU usage fix from Taehee Yoo.
3) Flow dissector needs nhoff and thoff clamping, from Stanislav
Fomichev.
4) Missing sin6_flowinfo initialization in SCTP, from Xin Long.
5) Spectrev1 in ipmr and ip6mr, from Gustavo A. R. Silva.
6) Fix r8169 crash when DEBUG_SHIRQ is enabled, from Heiner Kallweit.
7) Fix SKB leak in rtlwifi, from Larry Finger.
8) Fix state pruning in bpf verifier, from Jakub Kicinski.
9) Don't handle completely duplicate fragments as overlapping, from
Michal Kubecek.
10) Fix memory corruption with macb and 64-bit DMA, from Anssi Hannula.
11) Fix TCP fallback socket release in smc, from Myungho Jung.
12) gro_cells_destroy needs to napi_disable, from Lorenzo Bianconi.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (130 commits)
rds: Fix warning.
neighbor: NTF_PROXY is a valid ndm_flag for a dump request
net: mvpp2: fix the phylink mode validation
net/sched: cls_flower: Remove old entries from rhashtable
net/tls: allocate tls context using GFP_ATOMIC
iptunnel: make TUNNEL_FLAGS available in uapi
gro_cell: add napi_disable in gro_cells_destroy
lan743x: Remove MAC Reset from initialization
net/mlx5e: Remove the false indication of software timestamping support
net/mlx5: Typo fix in del_sw_hw_rule
net/mlx5e: RX, Fix wrong early return in receive queue poll
ipv6: explicitly initialize udp6_addr in udp_sock_create6()
bnxt_en: Fix ethtool self-test loopback.
net/rds: remove user triggered WARN_ON in rds_sendmsg
net/rds: fix warn in rds_message_alloc_sgs
ath10k: skip sending quiet mode cmd for WCN3990
mac80211: free skb fraglist before freeing the skb
nl80211: fix memory leak if validate_pae_over_nl80211() fails
net/smc: fix TCP fallback socket release
vxge: ensure data0 is initialized in when fetching firmware version information
...
Stefan reported, that the glibc tst-robustpi4 test case fails
occasionally. That case creates the following race between
sys_exit() and sys_futex_lock_pi():
CPU0 CPU1
sys_exit() sys_futex()
do_exit() futex_lock_pi()
exit_signals(tsk) No waiters:
tsk->flags |= PF_EXITING; *uaddr == 0x00000PID
mm_release(tsk) Set waiter bit
exit_robust_list(tsk) { *uaddr = 0x80000PID;
Set owner died attach_to_pi_owner() {
*uaddr = 0xC0000000; tsk = get_task(PID);
} if (!tsk->flags & PF_EXITING) {
... attach();
tsk->flags |= PF_EXITPIDONE; } else {
if (!(tsk->flags & PF_EXITPIDONE))
return -EAGAIN;
return -ESRCH; <--- FAIL
}
ESRCH is returned all the way to user space, which triggers the glibc test
case assert. Returning ESRCH unconditionally is wrong here because the user
space value has been changed by the exiting task to 0xC0000000, i.e. the
FUTEX_OWNER_DIED bit is set and the futex PID value has been cleared. This
is a valid state and the kernel has to handle it, i.e. taking the futex.
Cure it by rereading the user space value when PF_EXITING and PF_EXITPIDONE
is set in the task which 'owns' the futex. If the value has changed, let
the kernel retry the operation, which includes all regular sanity checks
and correctly handles the FUTEX_OWNER_DIED case.
If it hasn't changed, then return ESRCH as there is no way to distinguish
this case from malfunctioning user space. This happens when the exiting
task did not have a robust list, the robust list was corrupted or the user
space value in the futex was simply bogus.
Reported-by: Stefan Liebler <stli@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200467
Link: https://lkml.kernel.org/r/20181210152311.986181245@linutronix.de
The dma_direct_supported() function intends to check the DMA mask against
specific values. However, the phys_to_dma() function includes the SME
encryption mask, which defeats the intended purpose of the check. This
results in drivers that support less than 48-bit DMA (SME encryption mask
is bit 47) from being able to set the DMA mask successfully when SME is
active, which results in the driver failing to initialize.
Change the function used to check the mask from phys_to_dma() to
__phys_to_dma() so that the SME encryption mask is not part of the check.
Fixes: c1d0af1a1d ("kernel/dma/direct: take DMA offset into account in dma_direct_supported")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Alexei Starovoitov says:
====================
pull-request: bpf 2018-12-15
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) fix liveness propagation of callee saved registers, from Jakub.
2) fix overflow in bpf_jit_limit knob, from Daniel.
3) bpf_flow_dissector api fix, from Stanislav.
4) bpf_perf_event api fix on powerpc, from Sandipan.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently for liveness and state pruning the register parentage
chains don't include states of the callee. This makes some sense
as the callee can't access those registers. However, this means
that READs done after the callee returns will not propagate into
the states of the callee. Callee will then perform pruning
disregarding differences in caller state.
Example:
0: (85) call bpf_user_rnd_u32
1: (b7) r8 = 0
2: (55) if r0 != 0x0 goto pc+1
3: (b7) r8 = 1
4: (bf) r1 = r8
5: (85) call pc+4
6: (15) if r8 == 0x1 goto pc+1
7: (05) *(u64 *)(r9 - 8) = r3
8: (b7) r0 = 0
9: (95) exit
10: (15) if r1 == 0x0 goto pc+0
11: (95) exit
Here we acquire unknown state with call to get_random() [1]. Then
we store this random state in r8 (either 0 or 1) [1 - 3], and make
a call on line 5. Callee does nothing but a trivial conditional
jump (to create a pruning point). Upon return caller checks the
state of r8 and either performs an unsafe read or not.
Verifier will first explore the path with r8 == 1, creating a pruning
point at [11]. The parentage chain for r8 will include only callers
states so once verifier reaches [6] it will mark liveness only on states
in the caller, and not [11]. Now when verifier walks the paths with
r8 == 0 it will reach [11] and since REG_LIVE_READ on r8 was not
propagated there it will prune the walk entirely (stop walking
the entire program, not just the callee). Since [6] was never walked
with r8 == 0, [7] will be considered dead and replaced with "goto -1"
causing hang at runtime.
This patch weaves the callee's explored states onto the callers
parentage chain. Rough parentage for r8 would have looked like this
before:
[0] [1] [2] [3] [4] [5] [10] [11] [6] [7]
| | ,---|----. | | |
sl0: sl0: / sl0: \ sl0: sl0: sl0:
fr0: r8 <-- fr0: r8<+--fr0: r8 `fr0: r8 ,fr0: r8<-fr0: r8
\ fr1: r8 <- fr1: r8 /
\__________________/
after:
[0] [1] [2] [3] [4] [5] [10] [11] [6] [7]
| | | | | |
sl0: sl0: sl0: sl0: sl0: sl0:
fr0: r8 <-- fr0: r8 <- fr0: r8 <- fr0: r8 <-fr0: r8<-fr0: r8
fr1: r8 <- fr1: r8
Now the mark from instruction 6 will travel through callees states.
Note that we don't have to connect r0 because its overwritten by
callees state on return and r1 - r5 because those are not alive
any more once a call is made.
v2:
- don't connect the callees registers twice (Alexei: suggestion & code)
- add more details to the comment (Ed & Alexei)
v1: don't unnecessarily link caller saved regs (Jiong)
Fixes: f4d7e40a5b ("bpf: introduce function calls (verification)")
Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull tracing fixes from Steven Rostedt:
"While running various ftrace tests on new development code, the
kmemleak detector found some allocations that were not freed
correctly.
This fixes a couple of leaks in the event trigger code as well as in
adding function trace filters in trace instances"
* tag 'trace-v4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix memory leak of instance function hash filters
tracing: Fix memory leak in set_trigger_filter()
tracing: Fix memory leak in create_filter()
Michael and Sandipan report:
Commit ede95a63b5 introduced a bpf_jit_limit tuneable to limit BPF
JIT allocations. At compile time it defaults to PAGE_SIZE * 40000,
and is adjusted again at init time if MODULES_VADDR is defined.
For ppc64 kernels, MODULES_VADDR isn't defined, so we're stuck with
the compile-time default at boot-time, which is 0x9c400000 when
using 64K page size. This overflows the signed 32-bit bpf_jit_limit
value:
root@ubuntu:/tmp# cat /proc/sys/net/core/bpf_jit_limit
-1673527296
and can cause various unexpected failures throughout the network
stack. In one case `strace dhclient eth0` reported:
setsockopt(5, SOL_SOCKET, SO_ATTACH_FILTER, {len=11, filter=0x105dd27f8},
16) = -1 ENOTSUPP (Unknown error 524)
and similar failures can be seen with tools like tcpdump. This doesn't
always reproduce however, and I'm not sure why. The more consistent
failure I've seen is an Ubuntu 18.04 KVM guest booted on a POWER9
host would time out on systemd/netplan configuring a virtio-net NIC
with no noticeable errors in the logs.
Given this and also given that in near future some architectures like
arm64 will have a custom area for BPF JIT image allocations we should
get rid of the BPF_JIT_LIMIT_DEFAULT fallback / default entirely. For
4.21, we have an overridable bpf_jit_alloc_exec(), bpf_jit_free_exec()
so therefore add another overridable bpf_jit_alloc_exec_limit() helper
function which returns the possible size of the memory area for deriving
the default heuristic in bpf_jit_charge_init().
Like bpf_jit_alloc_exec() and bpf_jit_free_exec(), the new
bpf_jit_alloc_exec_limit() assumes that module_alloc() is the default
JIT memory provider, and therefore in case archs implement their custom
module_alloc() we use MODULES_{END,_VADDR} for limits and otherwise for
vmalloc_exec() cases like on ppc64 we use VMALLOC_{END,_START}.
Additionally, for archs supporting large page sizes, we should change
the sysctl to be handled as long to not run into sysctl restrictions
in future.
Fixes: ede95a63b5 ("bpf: add bpf_jit_limit knob to restrict unpriv allocations")
Reported-by: Sandipan Das <sandipan@linux.ibm.com>
Reported-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The following commands will cause a memory leak:
# cd /sys/kernel/tracing
# mkdir instances/foo
# echo schedule > instance/foo/set_ftrace_filter
# rmdir instances/foo
The reason is that the hashes that hold the filters to set_ftrace_filter and
set_ftrace_notrace are not freed if they contain any data on the instance
and the instance is removed.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: 591dffdade ("ftrace: Allow for function tracing instance to filter functions")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When create_event_filter() fails in set_trigger_filter(), the filter may
still be allocated and needs to be freed. The caller expects the
data->filter to be updated with the new filter, even if the new filter
failed (we could add an error message by setting set_str parameter of
create_event_filter(), but that's another update).
But because the error would just exit, filter was left hanging and
nothing could free it.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: bac5fb97a1 ("tracing: Add and use generic set_trigger_filter() implementation")
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The create_filter() calls create_filter_start() which allocates a
"parse_error" descriptor, but fails to call create_filter_finish() that
frees it.
The op_stack and inverts in predicate_parse() were also not freed.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: 80765597bc ("tracing: Rewrite filter logic to be simpler and faster")
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull networking fixes from David Miller:
"A decent batch of fixes here. I'd say about half are for problems that
have existed for a while, and half are for new regressions added in
the 4.20 merge window.
1) Fix 10G SFP phy module detection in mvpp2, from Baruch Siach.
2) Revert bogus emac driver change, from Benjamin Herrenschmidt.
3) Handle BPF exported data structure with pointers when building
32-bit userland, from Daniel Borkmann.
4) Memory leak fix in act_police, from Davide Caratti.
5) Check RX checksum offload in RX descriptors properly in aquantia
driver, from Dmitry Bogdanov.
6) SKB unlink fix in various spots, from Edward Cree.
7) ndo_dflt_fdb_dump() only works with ethernet, enforce this, from
Eric Dumazet.
8) Fix FID leak in mlxsw driver, from Ido Schimmel.
9) IOTLB locking fix in vhost, from Jean-Philippe Brucker.
10) Fix SKB truesize accounting in ipv4/ipv6/netfilter frag memory
limits otherwise namespace exit can hang. From Jiri Wiesner.
11) Address block parsing length fixes in x25 from Martin Schiller.
12) IRQ and ring accounting fixes in bnxt_en, from Michael Chan.
13) For tun interfaces, only iface delete works with rtnl ops, enforce
this by disallowing add. From Nicolas Dichtel.
14) Use after free in liquidio, from Pan Bian.
15) Fix SKB use after passing to netif_receive_skb(), from Prashant
Bhole.
16) Static key accounting and other fixes in XPS from Sabrina Dubroca.
17) Partially initialized flow key passed to ip6_route_output(), from
Shmulik Ladkani.
18) Fix RTNL deadlock during reset in ibmvnic driver, from Thomas
Falcon.
19) Several small TCP fixes (off-by-one on window probe abort, NULL
deref in tail loss probe, SNMP mis-estimations) from Yuchung
Cheng"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (93 commits)
net/sched: cls_flower: Reject duplicated rules also under skip_sw
bnxt_en: Fix _bnxt_get_max_rings() for 57500 chips.
bnxt_en: Fix NQ/CP rings accounting on the new 57500 chips.
bnxt_en: Keep track of reserved IRQs.
bnxt_en: Fix CNP CoS queue regression.
net/mlx4_core: Correctly set PFC param if global pause is turned off.
Revert "net/ibm/emac: wrong bit is used for STA control"
neighbour: Avoid writing before skb->head in neigh_hh_output()
ipv6: Check available headroom in ip6_xmit() even without options
tcp: lack of available data can also cause TSO defer
ipv6: sr: properly initialize flowi6 prior passing to ip6_route_output
mlxsw: spectrum_switchdev: Fix VLAN device deletion via ioctl
mlxsw: spectrum_router: Relax GRE decap matching check
mlxsw: spectrum_switchdev: Avoid leaking FID's reference count
mlxsw: spectrum_nve: Remove easily triggerable warnings
ipv4: ipv6: netfilter: Adjust the frag mem limit when truesize changes
sctp: frag_point sanity check
tcp: fix NULL ref in tail loss probe
tcp: Do not underestimate rwnd_limited
net: use skb_list_del_init() to remove from RX sublists
...
Pull gcc stackleak plugin fixes from Kees Cook:
- Remove tracing for inserted stack depth marking function (Anders
Roxell)
- Move gcc-plugin pass location to avoid objtool warnings (Alexander
Popov)
* tag 'gcc-plugins-v4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
stackleak: Register the 'stackleak_cleanup' pass before the '*free_cfg' pass
stackleak: Mark stackleak_track_stack() as notrace
Pull tracing fix from Steven Rostedt:
"This is a single commit that fixes a bug in uprobes SDT code due to a
missing mutex protection"
* tag 'trace-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
Uprobes: Fix kernel oops with delayed_uprobe_remove()
Function graph tracing recurses into itself when stackleak is enabled,
causing the ftrace graph selftest to run for up to 90 seconds and
trigger the softlockup watchdog.
Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200
200 mcount_get_lr_addr x0 // pointer to function's saved lr
(gdb) bt
\#0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200
\#1 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153
\#2 0xffffff8008555484 in stackleak_track_stack () at ../kernel/stackleak.c:106
\#3 0xffffff8008421ff8 in ftrace_ops_test (ops=0xffffff8009eaa840 <graph_ops>, ip=18446743524091297036, regs=<optimized out>) at ../kernel/trace/ftrace.c:1507
\#4 0xffffff8008428770 in __ftrace_ops_list_func (regs=<optimized out>, ignored=<optimized out>, parent_ip=<optimized out>, ip=<optimized out>) at ../kernel/trace/ftrace.c:6286
\#5 ftrace_ops_no_ops (ip=18446743524091297036, parent_ip=18446743524091242824) at ../kernel/trace/ftrace.c:6321
\#6 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153
\#7 0xffffff800832fd10 in irq_find_mapping (domain=0xffffffc03fc4bc80, hwirq=27) at ../kernel/irq/irqdomain.c:876
\#8 0xffffff800832294c in __handle_domain_irq (domain=0xffffffc03fc4bc80, hwirq=27, lookup=true, regs=0xffffff800814b840) at ../kernel/irq/irqdesc.c:650
\#9 0xffffff80081d52b4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:205
Rework so we mark stackleak_track_stack as notrace
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Alexei Starovoitov says:
====================
pull-request: bpf 2018-12-05
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) fix bpf uapi pointers for 32-bit architectures, from Daniel.
2) improve verifer ability to handle progs with a lot of branches, from Alexei.
3) strict btf checks, from Yonghong.
4) bpf_sk_lookup api cleanup, from Joe.
5) other misc fixes
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
malicious bpf program may try to force the verifier to remember
a lot of distinct verifier states.
Put a limit to number of per-insn 'struct bpf_verifier_state'.
Note that hitting the limit doesn't reject the program.
It potentially makes the verifier do more steps to analyze the program.
It means that malicious programs will hit BPF_COMPLEXITY_LIMIT_INSNS sooner
instead of spending cpu time walking long link list.
The limit of BPF_COMPLEXITY_LIMIT_STATES==64 affects cilium progs
with slight increase in number of "steps" it takes to successfully verify
the programs:
before after
bpf_lb-DLB_L3.o 1940 1940
bpf_lb-DLB_L4.o 3089 3089
bpf_lb-DUNKNOWN.o 1065 1065
bpf_lxc-DDROP_ALL.o 28052 | 28162
bpf_lxc-DUNKNOWN.o 35487 | 35541
bpf_netdev.o 10864 10864
bpf_overlay.o 6643 6643
bpf_lcx_jit.o 38437 38437
But it also makes malicious program to be rejected in 0.4 seconds vs 6.5
Hence apply this limit to unprivileged programs only.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
pathological bpf programs may try to force verifier to explode in
the number of branch states:
20: (d5) if r1 s<= 0x24000028 goto pc+0
21: (b5) if r0 <= 0xe1fa20 goto pc+2
22: (d5) if r1 s<= 0x7e goto pc+0
23: (b5) if r0 <= 0xe880e000 goto pc+0
24: (c5) if r0 s< 0x2100ecf4 goto pc+0
25: (d5) if r1 s<= 0xe880e000 goto pc+1
26: (c5) if r0 s< 0xf4041810 goto pc+0
27: (d5) if r1 s<= 0x1e007e goto pc+0
28: (b5) if r0 <= 0xe86be000 goto pc+0
29: (07) r0 += 16614
30: (c5) if r0 s< 0x6d0020da goto pc+0
31: (35) if r0 >= 0x2100ecf4 goto pc+0
Teach verifier to recognize always taken and always not taken branches.
This analysis is already done for == and != comparison.
Expand it to all other branches.
It also helps real bpf programs to be verified faster:
before after
bpf_lb-DLB_L3.o 2003 1940
bpf_lb-DLB_L4.o 3173 3089
bpf_lb-DUNKNOWN.o 1080 1065
bpf_lxc-DDROP_ALL.o 29584 28052
bpf_lxc-DUNKNOWN.o 36916 35487
bpf_netdev.o 11188 10864
bpf_overlay.o 6679 6643
bpf_lcx_jit.o 39555 38437
Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Malicious user space may try to force the verifier to use as much cpu
time and memory as possible. Hence check for pending signals
while verifying the program.
Note that suspend of sys_bpf(PROG_LOAD) syscall will lead to EAGAIN,
since the kernel has to release the resources used for program verification.
Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Pull STIBP fallout fixes from Thomas Gleixner:
"The performance destruction department finally got it's act together
and came up with a cure for the STIPB regression:
- Provide a command line option to control the spectre v2 user space
mitigations. Default is either seccomp or prctl (if seccomp is
disabled in Kconfig). prctl allows mitigation opt-in, seccomp
enables the migitation for sandboxed processes.
- Rework the code to handle the conditional STIBP/IBPB control and
remove the now unused ptrace_may_access_sched() optimization
attempt
- Disable STIBP automatically when SMT is disabled
- Optimize the switch_to() logic to avoid MSR writes and invocations
of __switch_to_xtra().
- Make the asynchronous speculation TIF updates synchronous to
prevent stale mitigation state.
As a general cleanup this also makes retpoline directly depend on
compiler support and removes the 'minimal retpoline' option which just
pretended to provide some form of security while providing none"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
x86/speculation: Provide IBPB always command line options
x86/speculation: Add seccomp Spectre v2 user space protection mode
x86/speculation: Enable prctl mode for spectre_v2_user
x86/speculation: Add prctl() control for indirect branch speculation
x86/speculation: Prepare arch_smt_update() for PRCTL mode
x86/speculation: Prevent stale SPEC_CTRL msr content
x86/speculation: Split out TIF update
ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS
x86/speculation: Prepare for conditional IBPB in switch_mm()
x86/speculation: Avoid __switch_to_xtra() calls
x86/process: Consolidate and simplify switch_to_xtra() code
x86/speculation: Prepare for per task indirect branch speculation control
x86/speculation: Add command line control for indirect branch speculation
x86/speculation: Unify conditional spectre v2 print functions
x86/speculataion: Mark command line parser data __initdata
x86/speculation: Mark string arrays const correctly
x86/speculation: Reorder the spec_v2 code
x86/l1tf: Show actual SMT state
x86/speculation: Rework SMT state change
sched/smt: Expose sched_smt_present static key
...
Merge misc fixes from Andrew Morton:
"31 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (31 commits)
ocfs2: fix potential use after free
mm/khugepaged: fix the xas_create_range() error path
mm/khugepaged: collapse_shmem() do not crash on Compound
mm/khugepaged: collapse_shmem() without freezing new_page
mm/khugepaged: minor reorderings in collapse_shmem()
mm/khugepaged: collapse_shmem() remember to clear holes
mm/khugepaged: fix crashes due to misaccounted holes
mm/khugepaged: collapse_shmem() stop if punched or truncated
mm/huge_memory: fix lockdep complaint on 32-bit i_size_read()
mm/huge_memory: splitting set mapping+index before unfreeze
mm/huge_memory: rename freeze_page() to unmap_page()
initramfs: clean old path before creating a hardlink
kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
psi: make disabling/enabling easier for vendor kernels
proc: fixup map_files test on arm
debugobjects: avoid recursive calls with kmemleak
userfaultfd: shmem: UFFDIO_COPY: set the page dirty if VM_WRITE is not set
userfaultfd: shmem: add i_size checks
userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas
userfaultfd: shmem: allocate anonymous memory for MAP_PRIVATE shmem
...
Rik van Riel
Linus Torvalds
Thomas Gleixner
Lendacky, Thomas
David S. Miller
Jakub Kicinski
Daniel Borkmann
Steven Rostedt (VMware)
Ravi Bangoria
Anders Roxell
Alexei Starovoitov