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Filename Latest commit message Latest commit date
Mark Rutland 3c197fdd07 arm64: fix compat syscall return truncation
commit e30e8d46cf605d216a799a28c77b8a41c328613a upstream.

Due to inconsistencies in the way we manipulate compat GPRs, we have a
few issues today:

* For audit and tracing, where error codes are handled as a (native)
  long, negative error codes are expected to be sign-extended to the
  native 64-bits, or they may fail to be matched correctly. Thus a
  syscall which fails with an error may erroneously be identified as
  failing.

* For ptrace, *all* compat return values should be sign-extended for
  consistency with 32-bit arm, but we currently only do this for
  negative return codes.

* As we may transiently set the upper 32 bits of some compat GPRs while
  in the kernel, these can be sampled by perf, which is somewhat
  confusing. This means that where a syscall returns a pointer above 2G,
  this will be sign-extended, but will not be mistaken for an error as
  error codes are constrained to the inclusive range [-4096, -1] where
  no user pointer can exist.

To fix all of these, we must consistently use helpers to get/set the
compat GPRs, ensuring that we never write the upper 32 bits of the
return code, and always sign-extend when reading the return code.  This
patch does so, with the following changes:

* We re-organise syscall_get_return_value() to always sign-extend for
  compat tasks, and reimplement syscall_get_error() atop. We update
  syscall_trace_exit() to use syscall_get_return_value().

* We consistently use syscall_set_return_value() to set the return
  value, ensureing the upper 32 bits are never set unexpectedly.

* As the core audit code currently uses regs_return_value() rather than
  syscall_get_return_value(), we special-case this for
  compat_user_mode(regs) such that this will do the right thing. Going
  forward, we should try to move the core audit code over to
  syscall_get_return_value().

Cc: <stable@vger.kernel.org>
Reported-by: He Zhe <zhe.he@windriver.com>
Reported-by: weiyuchen <weiyuchen3@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210802104200.21390-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
[Mark: trivial conflict resolution for v5.4.y]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-12 13:21:05 +02:00
arch arm64: fix compat syscall return truncation 2021-08-12 13:21:05 +02:00
block blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() 2021-08-12 13:20:58 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation userfaultfd: do not untag user pointers 2021-07-28 13:31:01 +02:00
drivers net/qla3xxx: fix schedule while atomic in ql_wait_for_drvr_lock and ql_adapter_reset 2021-08-12 13:21:05 +02:00
fs reiserfs: check directory items on read from disk 2021-08-12 13:21:05 +02:00
include tee: add tee_shm_alloc_kernel_buf() 2021-08-12 13:21:01 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel timers: Move clearing of base::timer_running under base:: Lock 2021-08-12 13:21:03 +02:00
lib lib/decompress_unlz4.c: correctly handle zero-padding around initrds. 2021-07-20 16:10:46 +02:00
LICENSES
mm mm: slab: fix kmem_cache_create failed when sysfs node not destroyed 2021-07-25 14:35:14 +02:00
net Bluetooth: defer cleanup of resources in hci_unregister_dev() 2021-08-12 13:20:58 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:53:30 +02:00
scripts scripts/tracing: fix the bug that can't parse raw_trace_func 2021-08-12 13:21:00 +02:00
security smackfs: restrict bytes count in smk_set_cipso() 2021-07-19 08:53:18 +02:00
sound ALSA: usb-audio: Add registration quirk for JBL Quantum 600 2021-08-12 13:20:59 +02:00
tools bpf, selftests: Adjust few selftest result_unpriv outcomes 2021-08-12 13:21:04 +02:00
usr
virt KVM: Do not leak memory for duplicate debugfs directories 2021-08-12 13:21:03 +02:00
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Makefile Linux 5.4.139 2021-08-08 09:04:09 +02:00
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