We must properly handle an errors when we increase the rlimit counter
and the ucounts reference counter. We have to this with RCU protection
to prevent possible use-after-free that could occur due to concurrent
put_cred_rcu().
The following reproducer triggers the problem:
$ cat testcase.sh
case "${STEP:-0}" in
0)
ulimit -Si 1
ulimit -Hi 1
STEP=1 unshare -rU "$0"
killall sleep
;;
1)
for i in 1 2 3 4 5; do unshare -rU sleep 5 & done
;;
esac
with the KASAN report being along the lines of
BUG: KASAN: use-after-free in put_ucounts+0x17/0xa0
Write of size 4 at addr ffff8880045f031c by task swapper/2/0
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.13.0+ #19
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-alt4 04/01/2014
Call Trace:
<IRQ>
put_ucounts+0x17/0xa0
put_cred_rcu+0xd5/0x190
rcu_core+0x3bf/0xcb0
__do_softirq+0xe3/0x341
irq_exit_rcu+0xbe/0xe0
sysvec_apic_timer_interrupt+0x6a/0x90
</IRQ>
asm_sysvec_apic_timer_interrupt+0x12/0x20
default_idle_call+0x53/0x130
do_idle+0x311/0x3c0
cpu_startup_entry+0x14/0x20
secondary_startup_64_no_verify+0xc2/0xcb
Allocated by task 127:
kasan_save_stack+0x1b/0x40
__kasan_kmalloc+0x7c/0x90
alloc_ucounts+0x169/0x2b0
set_cred_ucounts+0xbb/0x170
ksys_unshare+0x24c/0x4e0
__x64_sys_unshare+0x16/0x20
do_syscall_64+0x37/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 0:
kasan_save_stack+0x1b/0x40
kasan_set_track+0x1c/0x30
kasan_set_free_info+0x20/0x30
__kasan_slab_free+0xeb/0x120
kfree+0xaa/0x460
put_cred_rcu+0xd5/0x190
rcu_core+0x3bf/0xcb0
__do_softirq+0xe3/0x341
The buggy address belongs to the object at ffff8880045f0300
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 28 bytes inside of
192-byte region [ffff8880045f0300, ffff8880045f03c0)
The buggy address belongs to the page:
page:000000008de0a388 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880045f0000 pfn:0x45f0
flags: 0x100000000000200(slab|node=0|zone=1)
raw: 0100000000000200 ffffea00000f4640 0000000a0000000a ffff888001042a00
raw: ffff8880045f0000 000000008010000d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880045f0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880045f0280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880045f0300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880045f0380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8880045f0400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Disabling lock debugging due to kernel taint
Fixes: d646969055 ("Reimplement RLIMIT_SIGPENDING on top of ucounts")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull more ACPI updates from Rafael Wysocki:
"These include fixes of the recently introduced support for the
Platform Runtime Mechanism (PRM) feature, a new backlight quirk, a
suspend-to-idle wakeup fix for non-Intel platforms and a fix for the
AMBA bus resource list in /proc/iomem.
Specifics:
- Fix up the recently added Platform Runtime Mechanism (PRM) support
by correnting a couple of implementation mistakes in it and adding
a Kconfig help text to describe it (Aubrey Li, Rafael Wysocki).
- Add backlight quirk for Dell Vostro 3350 (Hans de Goede).
- Avoid spurious wakeups from suspend-to-idle on non-Intel platforms
by restricting special EC GPE handling to the Intel ones (Mario
Limonciello).
- Modify the AMBA bus support in ACPI to avoid adding using resource
names in /proc/iomem (Liguang Zhang)"
* tag 'acpi-5.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: Do not singal PRM support if not enabled
ACPI: Correct \_SB._OSC bit definition for PRM
ACPI: Kconfig: Provide help text for the ACPI_PRMT option
ACPI: PM: Only mark EC GPE for wakeup on Intel systems
ACPI: video: Add quirk for the Dell Vostro 3350
ACPI: AMBA: Fix resource name in /proc/iomem
Pull more power management updates from Rafael Wysocki:
"These include cpufreq core simplifications and fixes, cpufreq driver
updates, cpuidle driver update, a generic power domains (genpd)
locking fix and a debug-related simplification of the PM core.
Specifics:
- Drop the ->stop_cpu() (not really useful) and ->resolve_freq()
(unused) cpufreq driver callbacks and modify the users of the
former accordingly (Viresh Kumar, Rafael Wysocki).
- Add frequency invariance support to the ACPI CPPC cpufreq driver
again along with the related fixes and cleanups (Viresh Kumar).
- Update the Meditak, qcom and SCMI ARM cpufreq drivers (Fabien
Parent, Seiya Wang, Sibi Sankar, Christophe JAILLET).
- Rename black/white-lists in the DT cpufreq driver (Viresh Kumar).
- Add generic performance domains support to the dvfs DT bindings
(Sudeep Holla).
- Refine locking in the generic power domains (genpd) support code to
avoid lock dependency issues (Stephen Boyd).
- Update the MSM and qcom ARM cpuidle drivers (Bartosz Dudziak).
- Simplify the PM core debug code by using ktime_us_delta() to
compute time interval lengths (Mark-PK Tsai)"
* tag 'pm-5.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (21 commits)
PM: domains: Shrink locking area of the gpd_list_lock
PM: sleep: Use ktime_us_delta() in initcall_debug_report()
cpufreq: CPPC: Add support for frequency invariance
arch_topology: Avoid use-after-free for scale_freq_data
cpufreq: CPPC: Pass structure instance by reference
cpufreq: CPPC: Fix potential memleak in cppc_cpufreq_cpu_init
cpufreq: Remove ->resolve_freq()
cpufreq: Reuse cpufreq_driver_resolve_freq() in __cpufreq_driver_target()
cpufreq: Remove the ->stop_cpu() driver callback
cpufreq: powernv: Migrate to ->exit() callback instead of ->stop_cpu()
cpufreq: CPPC: Migrate to ->exit() callback instead of ->stop_cpu()
cpufreq: intel_pstate: Combine ->stop_cpu() and ->offline()
cpuidle: qcom: Add SPM register data for MSM8226
dt-bindings: arm: msm: Add SAW2 for MSM8226
dt-bindings: cpufreq: update cpu type and clock name for MT8173 SoC
clk: mediatek: remove deprecated CLK_INFRA_CA57SEL for MT8173 SoC
cpufreq: dt: Rename black/white-lists
cpufreq: scmi: Fix an error message
cpufreq: mediatek: add support for mt8365
dt-bindings: dvfs: Add support for generic performance domains
...
Pull nfsd updates from Bruce Fields:
- add tracepoints for callbacks and for client creation and destruction
- cache the mounts used for server-to-server copies
- expose callback information in /proc/fs/nfsd/clients/*/info
- don't hold locks unnecessarily while waiting for commits
- update NLM to use xdr_stream, as we have for NFSv2/v3/v4
* tag 'nfsd-5.14' of git://linux-nfs.org/~bfields/linux: (69 commits)
nfsd: fix NULL dereference in nfs3svc_encode_getaclres
NFSD: Prevent a possible oops in the nfs_dirent() tracepoint
nfsd: remove redundant assignment to pointer 'this'
nfsd: Reduce contention for the nfsd_file nf_rwsem
lockd: Update the NLMv4 SHARE results encoder to use struct xdr_stream
lockd: Update the NLMv4 nlm_res results encoder to use struct xdr_stream
lockd: Update the NLMv4 TEST results encoder to use struct xdr_stream
lockd: Update the NLMv4 void results encoder to use struct xdr_stream
lockd: Update the NLMv4 FREE_ALL arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 SHARE arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 SM_NOTIFY arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 nlm_res arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 UNLOCK arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 CANCEL arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 LOCK arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 TEST arguments decoder to use struct xdr_stream
lockd: Update the NLMv4 void arguments decoder to use struct xdr_stream
lockd: Update the NLMv1 SHARE results encoder to use struct xdr_stream
lockd: Update the NLMv1 nlm_res results encoder to use struct xdr_stream
lockd: Update the NLMv1 TEST results encoder to use struct xdr_stream
...
Pull module updates from Jessica Yu:
- Fix incorrect logic in module_kallsyms_on_each_symbol()
- Fix for a Coccinelle warning
* tag 'modules-for-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: correctly exit module_kallsyms_on_each_symbol when fn() != 0
kernel/module: Use BUG_ON instead of if condition followed by BUG
* acpi-misc:
ACPI: AMBA: Fix resource name in /proc/iomem
* acpi-video:
ACPI: video: Add quirk for the Dell Vostro 3350
* acpi-prm:
ACPI: Do not singal PRM support if not enabled
ACPI: Correct \_SB._OSC bit definition for PRM
ACPI: Kconfig: Provide help text for the ACPI_PRMT option
* pm-cpuidle:
cpuidle: qcom: Add SPM register data for MSM8226
dt-bindings: arm: msm: Add SAW2 for MSM8226
* pm-sleep:
PM: sleep: Use ktime_us_delta() in initcall_debug_report()
* pm-domains:
PM: domains: Shrink locking area of the gpd_list_lock
Pull x86 fpu updates from Thomas Gleixner:
"Fixes and improvements for FPU handling on x86:
- Prevent sigaltstack out of bounds writes.
The kernel unconditionally writes the FPU state to the alternate
stack without checking whether the stack is large enough to
accomodate it.
Check the alternate stack size before doing so and in case it's too
small force a SIGSEGV instead of silently corrupting user space
data.
- MINSIGSTKZ and SIGSTKSZ are constants in signal.h and have never
been updated despite the fact that the FPU state which is stored on
the signal stack has grown over time which causes trouble in the
field when AVX512 is available on a CPU. The kernel does not expose
the minimum requirements for the alternate stack size depending on
the available and enabled CPU features.
ARM already added an aux vector AT_MINSIGSTKSZ for the same reason.
Add it to x86 as well.
- A major cleanup of the x86 FPU code. The recent discoveries of
XSTATE related issues unearthed quite some inconsistencies,
duplicated code and other issues.
The fine granular overhaul addresses this, makes the code more
robust and maintainable, which allows to integrate upcoming XSTATE
related features in sane ways"
* tag 'x86-fpu-2021-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi_buf() again
x86/fpu/signal: Let xrstor handle the features to init
x86/fpu/signal: Handle #PF in the direct restore path
x86/fpu: Return proper error codes from user access functions
x86/fpu/signal: Split out the direct restore code
x86/fpu/signal: Sanitize copy_user_to_fpregs_zeroing()
x86/fpu/signal: Sanitize the xstate check on sigframe
x86/fpu/signal: Remove the legacy alignment check
x86/fpu/signal: Move initial checks into fpu__restore_sig()
x86/fpu: Mark init_fpstate __ro_after_init
x86/pkru: Remove xstate fiddling from write_pkru()
x86/fpu: Don't store PKRU in xstate in fpu_reset_fpstate()
x86/fpu: Remove PKRU handling from switch_fpu_finish()
x86/fpu: Mask PKRU from kernel XRSTOR[S] operations
x86/fpu: Hook up PKRU into ptrace()
x86/fpu: Add PKRU storage outside of task XSAVE buffer
x86/fpu: Dont restore PKRU in fpregs_restore_userspace()
x86/fpu: Rename xfeatures_mask_user() to xfeatures_mask_uabi()
x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to_fpregs()
x86/fpu: Rename __fpregs_load_activate() to fpregs_restore_userregs()
...
Pull xen updates from Juergen Gross:
"Only two minor patches this time: one cleanup patch and one patch
refreshing a Xen header"
* tag 'for-linus-5.14-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: sync include/xen/interface/io/ring.h with Xen's newest version
xen: Use DEVICE_ATTR_*() macro
Pull more fallthrough fixes from Gustavo Silva:
"Fix maore fall-through warnings when building the kernel with clang
and '-Wimplicit-fallthrough'"
* tag 'Wimplicit-fallthrough-clang-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
Input: Fix fall-through warning for Clang
scsi: aic94xx: Fix fall-through warning for Clang
i3c: master: cdns: Fix fall-through warning for Clang
net/mlx4: Fix fall-through warning for Clang
Pull hwspinlock updates from Bjorn Andersson:
"This adds a driver for the hardware spinlock in Allwinner sun6i"
* tag 'hwlock-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc:
dt-bindings: hwlock: sun6i: Fix various warnings in binding
hwspinlock: add sun6i hardware spinlock support
dt-bindings: hwlock: add sun6i_hwspinlock
Pull remoteproc updates from Bjorn Andersson:
"This adds support for controlling the PRU and R5F clusters on the TI
AM64x, the remote processor in i.MX7ULP, i.MX8MN/P and i.MX8ULP NXP
and the audio, compute and modem remoteprocs in the Qualcomm SC8180x
platform.
It fixes improper ordering of cdev and device creation of the
remoteproc control interface and it fixes resource leaks in the error
handling path of rproc_add() and the Qualcomm modem and wifi
remoteproc drivers.
Lastly it fixes a few build warnings and replace the dummy parameter
passed in the mailbox api of the stm32 driver to something not living
on the stack"
* tag 'rproc-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc: (32 commits)
remoteproc: qcom: pas: Add SC8180X adsp, cdsp and mpss
dt-bindings: remoteproc: qcom: pas: Add SC8180X adsp, cdsp and mpss
remoteproc: imx_rproc: support i.MX8ULP
dt-bindings: remoteproc: imx_rproc: support i.MX8ULP
remoteproc: stm32: fix mbox_send_message call
remoteproc: core: Cleanup device in case of failure
remoteproc: core: Fix cdev remove and rproc del
remoteproc: core: Move validate before device add
remoteproc: core: Move cdev add before device add
remoteproc: pru: Add support for various PRU cores on K3 AM64x SoCs
dt-bindings: remoteproc: pru: Update bindings for K3 AM64x SoCs
remoteproc: qcom_wcnss: Use devm_qcom_smem_state_get()
remoteproc: qcom_q6v5: Use devm_qcom_smem_state_get() to fix missing put()
soc: qcom: smem_state: Add devm_qcom_smem_state_get()
dt-bindings: remoteproc: qcom: pas: Fix indentation warnings
remoteproc: imx-rproc: Fix IMX_REMOTEPROC configuration
remoteproc: imx_rproc: support i.MX8MN/P
remoteproc: imx_rproc: support i.MX7ULP
remoteproc: imx_rproc: make clk optional
remoteproc: imx_rproc: initial support for mutilple start/stop method
...
In error cases the dentry may be NULL.
Before 20798dfe24, the encoder also checked dentry and
d_really_is_positive(dentry), but that looks like overkill to me--zero
status should be enough to guarantee a positive dentry.
This isn't the first time we've seen an error-case NULL dereference
hidden in the initialization of a local variable in an xdr encoder. But
I went back through the other recent rewrites and didn't spot any
similar bugs.
Reported-by: JianHong Yin <jiyin@redhat.com>
Reviewed-by: Chuck Lever III <chuck.lever@oracle.com>
Fixes: 20798dfe24 ("NFSD: Update the NFSv3 GETACL result encoder...")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The double copy of the string is a mistake, plus __assign_str()
uses strlen(), which is wrong to do on a string that isn't
guaranteed to be NUL-terminated.
Fixes: 6019ce0742 ("NFSD: Add a tracepoint to record directory entry encoding")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The pointer 'this' is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
When flushing out the unstable file writes as part of a COMMIT call, try
to perform most of of the data writes and waits outside the semaphore.
This means that if the client is sending the COMMIT as part of a memory
reclaim operation, then it can continue performing I/O, with contention
for the lock occurring only once the data sync is finished.
Fixes: 5011af4c69 ("nfsd: Fix stable writes")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add a .h file containing xdr_stream-based XDR helpers common to both
NLMv3 and NLMv4.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
To enable xdr_stream-based encoding and decoding, create a bespoke
RPC dispatch function for the lockd service.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
I'm not even sure cl_xprt can change here, but we're getting "suspicious
RCU usage" warnings, and other rpc_peeraddr2str callers are taking the
rcu lock.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The variable status is being initialized with a value that is never
read, the assignment is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Fix gcc W=1 warning:
fs/nfs_common/grace.c:91: warning: Function parameter or member 'net' not described in 'locks_in_grace'
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
