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Christophe Leroy d262a192d3 powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
Erhard reported the following KASAN hit while booting his PowerMac G4
with a KASAN-enabled kernel 6.13-rc6:

  BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
  Write of size 8 at addr f1000000 by task chronyd/1293

  CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G        W          6.13.0-rc6-PMacG4 #2
  Tainted: [W]=WARN
  Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
  Call Trace:
  [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
  [c24375b0] [c0504998] print_report+0xdc/0x504
  [c2437610] [c050475c] kasan_report+0xf8/0x108
  [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
  [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
  [c24376c0] [c004c014] patch_instructions+0x15c/0x16c
  [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
  [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
  [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
  [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
  [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
  [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
  [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
  [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
  [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
  --- interrupt: c00 at 0x5a1274
  NIP:  005a1274 LR: 006a3b3c CTR: 005296c8
  REGS: c2437f40 TRAP: 0c00   Tainted: G        W           (6.13.0-rc6-PMacG4)
  MSR:  0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 24004422  XER: 00000000

  GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932
  GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57
  GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002
  GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001
  NIP [005a1274] 0x5a1274
  LR [006a3b3c] 0x6a3b3c
  --- interrupt: c00

  The buggy address belongs to the virtual mapping at
   [f1000000, f1002000) created by:
   text_area_cpu_up+0x20/0x190

  The buggy address belongs to the physical page:
  page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30
  flags: 0x80000000(zone=2)
  raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001
  raw: 00000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
             ^
   f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
   f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  ==================================================================

f8 corresponds to KASAN_VMALLOC_INVALID which means the area is not
initialised hence not supposed to be used yet.

Powerpc text patching infrastructure allocates a virtual memory area
using get_vm_area() and flags it as VM_ALLOC. But that flag is meant
to be used for vmalloc() and vmalloc() allocated memory is not
supposed to be used before a call to __vmalloc_node_range() which is
never called for that area.

That went undetected until commit e4137f0881 ("mm, kasan, kmsan:
instrument copy_from/to_kernel_nofault")

The area allocated by text_area_cpu_up() is not vmalloc memory, it is
mapped directly on demand when needed by map_kernel_page(). There is
no VM flag corresponding to such usage, so just pass no flag. That way
the area will be unpoisonned and usable immediately.

Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Closes: https://lore.kernel.org/all/20250112135832.57c92322@yea/
Fixes: 37bc3e5fd7 ("powerpc/lib/code-patching: Use alternate map for patch_instruction()")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/06621423da339b374f48c0886e3a5db18e896be8.1739342693.git.christophe.leroy@csgroup.eu
2025-02-12 14:38:13 +05:30
arch powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC 2025-02-12 14:38:13 +05:30
block block-6.14-20250131 2025-01-31 11:49:30 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation ARM: 2025-02-09 09:41:38 -08:00
drivers Additional power management fix for 6.14-rc2 2025-02-09 09:47:06 -08:00
fs four SMB3 client fixes, 3 DFS related 2025-02-07 19:23:06 -08:00
include Kbuild fixes for v6.14 2025-02-09 10:05:32 -08:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring Fix a dangling pointer bug in the futex code used by the 2025-02-08 10:54:11 -08:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel seccomp fix for v6.14-rc2 2025-02-08 14:04:21 -08:00
lib hardening fixes for v6.14-rc2 2025-02-08 14:12:17 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm assorted stuff for this merge window 2025-02-01 15:07:56 -08:00
net vfs-6.14-rc2.fixes 2025-02-07 09:22:31 -08:00
rust rust: kbuild: do not export generated KASAN ODR symbols 2025-02-06 19:47:04 +01:00
samples AT_EXECVE_CHECK update for v6.14-rc1 (fix1) 2025-01-31 17:12:31 -08:00
scripts Kbuild fixes for v6.14 2025-02-09 10:05:32 -08:00
security treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
sound sound fixes for 6.14-rc1 2025-01-31 09:17:02 -08:00
tools ARM: 2025-02-09 09:41:38 -08:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap 21 hotfixes. 8 are cc:stable and the remainder address post-6.13 issues. 2025-02-01 09:49:20 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS gpio fixes for v6.14-rc2 2025-02-07 09:50:33 -08:00
Makefile Linux 6.14-rc2 2025-02-09 12:45:03 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.