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Daniel Borkmann ac616f7935 uaccess: Add strict non-pagefault kernel-space read function
[upstream commit 75a1a607bb7e6d918be3aca11ec2214a275392f4]

Add two new probe_kernel_read_strict() and strncpy_from_unsafe_strict()
helpers which by default alias to the __probe_kernel_read() and the
__strncpy_from_unsafe(), respectively, but can be overridden by archs
which have non-overlapping address ranges for kernel space and user
space in order to bail out with -EFAULT when attempting to probe user
memory including non-canonical user access addresses [0]:

  4-level page tables:
    user-space mem: 0x0000000000000000 - 0x00007fffffffffff
    non-canonical:  0x0000800000000000 - 0xffff7fffffffffff

  5-level page tables:
    user-space mem: 0x0000000000000000 - 0x00ffffffffffffff
    non-canonical:  0x0100000000000000 - 0xfeffffffffffffff

The idea is that these helpers are complementary to the probe_user_read()
and strncpy_from_unsafe_user() which probe user-only memory. Both added
helpers here do the same, but for kernel-only addresses.

Both set of helpers are going to be used for BPF tracing. They also
explicitly avoid throwing the splat for non-canonical user addresses from
00c42373d397 ("x86-64: add warning for non-canonical user access address
dereferences").

For compat, the current probe_kernel_read() and strncpy_from_unsafe() are
left as-is.

  [0] Documentation/x86/x86_64/mm.txt

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: x86@kernel.org
Link: https://lore.kernel.org/bpf/eefeefd769aa5a013531f491a71f0936779e916b.1572649915.git.daniel@iogearbox.net
2022-06-21 10:27:04 +08:00
Documentation kdump: update Documentation about crashkernel 2022-06-06 13:53:00 +08:00
LICENSES Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
arch uaccess: Add strict non-pagefault kernel-space read function 2022-06-21 10:27:04 +08:00
block block: dont count passthrough req as inflight 2022-06-01 10:11:12 +08:00
certs certs: Fix blacklist flag type confusion 2021-04-12 12:52:25 +08:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-20 16:07:34 +08:00
drivers net: tun: track dropped skb via kfree_skb_reason() 2022-06-17 10:08:51 +08:00
fs dax: Fix incorrect argument passed to xas_set_err() 2022-06-09 10:01:21 +08:00
include uaccess: Add strict non-pagefault kernel-space read function 2022-06-21 10:27:04 +08:00
init cgroup: bpf: make v1 support eBPF 2022-02-17 12:58:28 +08:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2021-03-16 16:27:51 +08:00
kernel cgroup: add cgroup.id to show each css id within a cgroup 2022-06-21 10:27:04 +08:00
lib libfdt: include fdt_addresses.c 2022-06-06 14:14:45 +08:00
mm uaccess: Add strict non-pagefault kernel-space read function 2022-06-21 10:27:04 +08:00
net bpf: Check types of arguments passed into helpers 2022-06-21 10:27:03 +08:00
package arm64/config: open CONFIG_IOSCHED_BFQ and CONFIG_BFQ_GROUP_IOSCHED 2022-06-10 17:13:42 +08:00
samples kfifo: fix ternary sign extension bugs 2021-05-20 16:08:01 +08:00
scripts kabi: kabi check support 2021-06-23 07:24:18 +00:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-20 16:07:35 +08:00
sound ALSA: usb: midi: don't return -ENOMEM when usb_urb_ep_type_check fails 2021-05-20 16:07:59 +08:00
tools bpf: Add attach_btf_id attribute to program load 2022-06-21 10:27:03 +08:00
usr Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
virt KVM: Stop looking for coalesced MMIO zones if the bus is destroyed 2021-05-20 16:07:44 +08:00
.clang-format Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
.cocciconfig Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
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Kconfig Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
MAINTAINERS x86/sgx: Update MAINTAINERS 2021-07-12 08:56:46 +00:00
Makefile Rebase to linux long term 5.4.119 2021-05-20 16:08:02 +08:00
README Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
README.md Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
backport_remove_lists.txt Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
tools_key.pub Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00

README.md

Tencent Linux Kernel 4.0