Commit Graph

144 Commits

Author SHA1 Message Date
Linus Torvalds
bc3012f4e3 Merge tag 'v6.7-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
 "API:
   - Add virtual-address based lskcipher interface
   - Optimise ahash/shash performance in light of costly indirect calls
   - Remove ahash alignmask attribute

  Algorithms:
   - Improve AES/XTS performance of 6-way unrolling for ppc
   - Remove some uses of obsolete algorithms (md4, md5, sha1)
   - Add FIPS 202 SHA-3 support in pkcs1pad
   - Add fast path for single-page messages in adiantum
   - Remove zlib-deflate

  Drivers:
   - Add support for S4 in meson RNG driver
   - Add STM32MP13x support in stm32
   - Add hwrng interface support in qcom-rng
   - Add support for deflate algorithm in hisilicon/zip"

* tag 'v6.7-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (283 commits)
  crypto: adiantum - flush destination page before unmapping
  crypto: testmgr - move pkcs1pad(rsa,sha3-*) to correct place
  Documentation/module-signing.txt: bring up to date
  module: enable automatic module signing with FIPS 202 SHA-3
  crypto: asymmetric_keys - allow FIPS 202 SHA-3 signatures
  crypto: rsa-pkcs1pad - Add FIPS 202 SHA-3 support
  crypto: FIPS 202 SHA-3 register in hash info for IMA
  x509: Add OIDs for FIPS 202 SHA-3 hash and signatures
  crypto: ahash - optimize performance when wrapping shash
  crypto: ahash - check for shash type instead of not ahash type
  crypto: hash - move "ahash wrapping shash" functions to ahash.c
  crypto: talitos - stop using crypto_ahash::init
  crypto: chelsio - stop using crypto_ahash::init
  crypto: ahash - improve file comment
  crypto: ahash - remove struct ahash_request_priv
  crypto: ahash - remove crypto_ahash_alignmask
  crypto: gcm - stop using alignmask of ahash
  crypto: chacha20poly1305 - stop using alignmask of ahash
  crypto: ccm - stop using alignmask of ahash
  net: ipv6: stop checking crypto_ahash_alignmask
  ...
2023-11-02 16:15:30 -10:00
Andrea Righi
17fc8084aa module/decompress: use kvmalloc() consistently
We consistently switched from kmalloc() to vmalloc() in module
decompression to prevent potential memory allocation failures with large
modules, however vmalloc() is not as memory-efficient and fast as
kmalloc().

Since we don't know in general the size of the workspace required by the
decompression algorithm, it is more reasonable to use kvmalloc()
consistently, also considering that we don't have special memory
requirements here.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-11-02 07:35:39 -10:00
Kees Cook
ea0b0bcef4 module: Annotate struct module_notes_attrs with __counted_by
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct module_notes_attrs.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-11-01 13:07:32 -07:00
Zhu Mao
fd06da7761 module: Fix comment typo
Delete duplicated word in comment.

Signed-off-by: Zhu Mao <zhumao001@208suo.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-11-01 13:07:08 -07:00
Andrea Righi
3737df782c module/decompress: use vmalloc() for gzip decompression workspace
Use a similar approach as commit a419beac4a ("module/decompress: use
vmalloc() for zstd decompression workspace") and replace kmalloc() with
vmalloc() also for the gzip module decompression workspace.

In this case the workspace is represented by struct inflate_workspace
that can be fairly large for kmalloc() and it can potentially lead to
allocation errors on certain systems:

$ pahole inflate_workspace
struct inflate_workspace {
	struct inflate_state       inflate_state;        /*     0  9544 */
	/* --- cacheline 149 boundary (9536 bytes) was 8 bytes ago --- */
	unsigned char              working_window[32768]; /*  9544 32768 */

	/* size: 42312, cachelines: 662, members: 2 */
	/* last cacheline: 8 bytes */
};

Considering that there is no need to use continuous physical memory,
simply switch to vmalloc() to provide a more reliable in-kernel module
decompression.

Fixes: b1ae6dc41e ("module: add in-kernel support for decompressing")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-11-01 13:07:08 -07:00
Dimitri John Ledkov
446b1e0b7b module: enable automatic module signing with FIPS 202 SHA-3
Add Kconfig options to use SHA-3 for kernel module signing. 256 size
for RSA only, and higher sizes for RSA and NIST P-384.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-27 18:04:30 +08:00
Dimitri John Ledkov
fc3225fd6f module: Do not offer sha224 for built-in module signing
sha224 does not provide enough security against collision attacks
relative to the default keys used for signing (RSA 4k & P-384). Also
sha224 never became popular, as sha256 got widely adopter ahead of
sha224 being introduced.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-20 13:39:26 +08:00
Dimitri John Ledkov
16ab7cb582 crypto: pkcs7 - remove sha1 support
Removes support for sha1 signed kernel modules, importing sha1 signed
x.509 certificates.

rsa-pkcs1pad keeps sha1 padding support, which seems to be used by
virtio driver.

sha1 remains available as there are many drivers and subsystems using
it. Note only hmac(sha1) with secret keys remains cryptographically
secure.

In the kernel there are filesystems, IMA, tpm/pcr that appear to be
using sha1. Maybe they can all start to be slowly upgraded to
something else i.e. blake3, ParallelHash, SHAKE256 as needed.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-20 13:39:26 +08:00
Andrea Righi
a419beac4a module/decompress: use vmalloc() for zstd decompression workspace
Using kmalloc() to allocate the decompression workspace for zstd may
trigger the following warning when large modules are loaded (i.e., xfs):

[    2.961884] WARNING: CPU: 1 PID: 254 at mm/page_alloc.c:4453 __alloc_pages+0x2c3/0x350
...
[    2.989033] Call Trace:
[    2.989841]  <TASK>
[    2.990614]  ? show_regs+0x6d/0x80
[    2.991573]  ? __warn+0x89/0x160
[    2.992485]  ? __alloc_pages+0x2c3/0x350
[    2.993520]  ? report_bug+0x17e/0x1b0
[    2.994506]  ? handle_bug+0x51/0xa0
[    2.995474]  ? exc_invalid_op+0x18/0x80
[    2.996469]  ? asm_exc_invalid_op+0x1b/0x20
[    2.997530]  ? module_zstd_decompress+0xdc/0x2a0
[    2.998665]  ? __alloc_pages+0x2c3/0x350
[    2.999695]  ? module_zstd_decompress+0xdc/0x2a0
[    3.000821]  __kmalloc_large_node+0x7a/0x150
[    3.001920]  __kmalloc+0xdb/0x170
[    3.002824]  module_zstd_decompress+0xdc/0x2a0
[    3.003857]  module_decompress+0x37/0xc0
[    3.004688]  init_module_from_file+0xd0/0x100
[    3.005668]  idempotent_init_module+0x11c/0x2b0
[    3.006632]  __x64_sys_finit_module+0x64/0xd0
[    3.007568]  do_syscall_64+0x59/0x90
[    3.008373]  ? ksys_read+0x73/0x100
[    3.009395]  ? exit_to_user_mode_prepare+0x30/0xb0
[    3.010531]  ? syscall_exit_to_user_mode+0x37/0x60
[    3.011662]  ? do_syscall_64+0x68/0x90
[    3.012511]  ? do_syscall_64+0x68/0x90
[    3.013364]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8

However, continuous physical memory does not seem to be required in
module_zstd_decompress(), so use vmalloc() instead, to prevent the
warning and avoid potential failures at loading compressed modules.

Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-08-29 09:39:08 -07:00
James Morse
2abcc4b5a6 module: Expose module_init_layout_section()
module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.

arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.

Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.

Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
|  module_emit_plt_entry+0x184/0x1cc
|  apply_relocate_add+0x2bc/0x8e4
|  load_module+0xe34/0x1bd4
|  init_module_from_file+0x84/0xc0
|  __arm64_sys_finit_module+0x1b8/0x27c
|  invoke_syscall.constprop.0+0x5c/0x104
|  do_el0_svc+0x58/0x160
|  el0_svc+0x38/0x110
|  el0t_64_sync_handler+0xc0/0xc4
|  el0t_64_sync+0x190/0x194

Instead of duplicating module_init_layout_section()s logic, expose it.

Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-08-03 13:42:02 -07:00
Christoph Hellwig
9011e49d54 modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules
It has recently come to my attention that nvidia is circumventing the
protection added in 262e6ae708 ("modules: inherit
TAINT_PROPRIETARY_MODULE") by importing exports from their proprietary
modules into an allegedly GPL licensed module and then rexporting them.

Given that symbol_get was only ever intended for tightly cooperating
modules using very internal symbols it is logical to restrict it to
being used on EXPORT_SYMBOL_GPL and prevent nvidia from costly DMCA
Circumvention of Access Controls law suites.

All symbols except for four used through symbol_get were already exported
as EXPORT_SYMBOL_GPL, and the remaining four ones were switched over in
the preparation patches.

Fixes: 262e6ae708 ("modules: inherit TAINT_PROPRIETARY_MODULE")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-08-02 11:18:22 -07:00
Palmer Dabbelt
ff09f6fd29 modpost, kallsyms: Treat add '$'-prefixed symbols as mapping symbols
Trying to restrict the '$'-prefix change to RISC-V caused some fallout,
so let's just treat all those symbols as special.

Fixes: c05780ef3c ("module: Ignore RISC-V mapping symbols too")
Link: https://lore.kernel.org/all/20230712015747.77263-1-wangkefeng.wang@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-07-24 12:09:47 -07:00
Palmer Dabbelt
c05780ef3c module: Ignore RISC-V mapping symbols too
RISC-V has an extended form of mapping symbols that we use to encode
the ISA when it changes in the middle of an ELF.  This trips up modpost
as a build failure, I haven't yet verified it yet but I believe the
kallsyms difference should result in stacks looking sane again.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-07-10 12:45:23 -07:00
Linus Torvalds
f196220715 module: fix init_module_from_file() error handling
Vegard Nossum pointed out two different problems with the error handling
in init_module_from_file():

 (a) the idempotent loading code didn't clean up properly in some error
     cases, leaving the on-stack 'struct idempotent' element still in
     the hash table

 (b) failure to read the module file would nonsensically update the
     'invalid_kread_bytes' stat counter with the error value

The first error is quite nasty, in that it can then cause subsequent
idempotent loads of that same file to access stale stack contents of the
previous failure.  The case may not happen in any normal situation
(explaining all the "Tested-by's on the original change), and requires
admin privileges, but syzkaller triggers random bad behavior as a
result:

    BUG: soft lockup in sys_finit_module
    BUG: unable to handle kernel paging request in init_module_from_file
    general protection fault in init_module_from_file
    INFO: task hung in init_module_from_file
    KASAN: out-of-bounds Read in init_module_from_file
    KASAN: slab-out-of-bounds Read in init_module_from_file
    ...

The second error is fairly benign and just leads to nonsensical stats
(and has been around since the debug stats were added).

Vegard also provided a patch for the idempotent loading issue, but I'd
rather re-organize the code and make it more legible using another level
of helper functions than add the usual "goto out" error handling.

Link: https://lore.kernel.org/lkml/20230704100852.23452-1-vegard.nossum@oracle.com/
Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reported-by: syzbot+9c2bdc9d24e4a7abe741@syzkaller.appspotmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-07-04 10:17:11 -07:00
Linus Torvalds
ad2885979e Merge tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Remove the deprecated rule to build *.dtbo from *.dts

 - Refactor section mismatch detection in modpost

 - Fix bogus ARM section mismatch detections

 - Fix error of 'make gtags' with O= option

 - Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error
   with the latest LLVM version

 - Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed

 - Ignore more compiler-generated symbols for kallsyms

 - Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles

 - Enable more kernel-doc warnings with W=2

 - Refactor <linux/export.h> by generating KSYMTAB data by modpost

 - Deprecate <asm/export.h> and <asm-generic/export.h>

 - Remove the EXPORT_DATA_SYMBOL macro

 - Move the check for static EXPORT_SYMBOL back to modpost, which makes
   the build faster

 - Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm

 - Warn missing MODULE_DESCRIPTION when building modules with W=1

 - Make 'make clean' robust against too long argument error

 - Exclude more objects from GCOV to fix CFI failures with GCOV

 - Allow 'make modules_install' to install modules.builtin and
   modules.builtin.modinfo even when CONFIG_MODULES is disabled

 - Include modules.builtin and modules.builtin.modinfo in the
   linux-image Debian package even when CONFIG_MODULES is disabled

 - Revive "Entering directory" logging for the latest Make version

* tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits)
  modpost: define more R_ARM_* for old distributions
  kbuild: revive "Entering directory" for Make >= 4.4.1
  kbuild: set correct abs_srctree and abs_objtree for package builds
  scripts/mksysmap: Ignore prefixed KCFI symbols
  kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb
  kbuild: builddeb: always make modules_install, to install modules.builtin*
  modpost: continue even with unknown relocation type
  modpost: factor out Elf_Sym pointer calculation to section_rel()
  modpost: factor out inst location calculation to section_rel()
  kbuild: Disable GCOV for *.mod.o
  kbuild: Fix CFI failures with GCOV
  kbuild: make clean rule robust against too long argument error
  script: modpost: emit a warning when the description is missing
  kbuild: make modules_install copy modules.builtin(.modinfo)
  linux/export.h: rename 'sec' argument to 'license'
  modpost: show offset from symbol for section mismatch warnings
  modpost: merge two similar section mismatch warnings
  kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
  modpost: use null string instead of NULL pointer for default namespace
  modpost: squash sym_update_namespace() into sym_add_exported()
  ...
2023-07-01 09:24:31 -07:00
Linus Torvalds
4e3c09e954 Merge tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull module updates from Luis Chamberlain:
 "The changes queued up for modules are pretty tame, mostly code removal
  of moving of code.

  Only two minor functional changes are made, the only one which stands
  out is Sebastian Andrzej Siewior's simplification of module reference
  counting by removing preempt_disable() and that has been tested on
  linux-next for well over a month without no regressions.

  I'm now, I guess, also a kitchen sink for some kallsyms changes"

[ There was a mis-communication about the concurrent module load changes
  that I had expected to come through Luis despite me authoring the
  patch. So some of the module updates were left hanging in the email
  ether, and I just committed them separately.

  It's my bad - I should have made it more clear that I expected my
  own patches to come through the module tree too. Now they missed
  linux-next, but hopefully that won't cause any issues    - Linus ]

* tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  kallsyms: make kallsyms_show_value() as generic function
  kallsyms: move kallsyms_show_value() out of kallsyms.c
  kallsyms: remove unsed API lookup_symbol_attrs
  kallsyms: remove unused arch_get_kallsym() helper
  module: Remove preempt_disable() from module reference counting.
2023-06-28 15:51:08 -07:00
Linus Torvalds
9b9879fc03 modules: catch concurrent module loads, treat them as idempotent
This is the new-and-improved attempt at avoiding huge memory load spikes
when the user space boot sequence tries to load hundreds (or even
thousands) of redundant duplicate modules in parallel.

See commit 9828ed3f69 ("module: error out early on concurrent load of
the same module file") for background and an earlier failed attempt that
was reverted.

That earlier attempt just said "concurrently loading the same module is
silly, just open the module file exclusively and return -ETXTBSY if
somebody else is already loading it".

While it is true that concurrent module loads of the same module is
silly, the reason that earlier attempt then failed was that the
concurrently loaded module would often be a prerequisite for another
module.

Thus failing to load the prerequisite would then cause cascading
failures of the other modules, rather than just short-circuiting that
one unnecessary module load.

At the same time, we still really don't want to load the contents of the
same module file hundreds of times, only to then wait for an eventually
successful load, and have everybody else return -EEXIST.

As a result, this takes another approach, and treats concurrent module
loads from the same file as "idempotent" in the inode.  So if one module
load is ongoing, we don't start a new one, but instead just wait for the
first one to complete and return the same return value as it did.

So unlike the first attempt, this does not return early: the intent is
not to speed up the boot, but to avoid a thundering herd problem in
allocating memory (both physical and virtual) for a module more than
once.

Also note that this does change behavior: it used to be that when you
had concurrent loads, you'd have one "winner" that would return success,
and everybody else would return -EEXIST.

In contrast, this idempotent logic goes all Oprah on the problem, and
says "You are a winner! And you are a winner! We are ALL winners".  But
since there's no possible actual real semantic difference between "you
loaded the module" and "somebody else already loaded the module", this
is more of a feel-good change than an actual honest-to-goodness semantic
change.

Of course, any true Johnny-come-latelies that don't get caught in the
concurrency filter will still return -EEXIST.  It's no different from
not even getting a seat at an Oprah taping.  That's life.

See the long thread on the kernel mailing list about this all, which
includes some numbers for memory use before and after the patch.

Link: https://lore.kernel.org/lkml/20230524213620.3509138-1-mcgrof@kernel.org/
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Tested-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Rudi Heitbaum <rudi@heitbaum..com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-06-28 15:46:44 -07:00
Linus Torvalds
054a73009c module: split up 'finit_module()' into init_module_from_file() helper
This will simplify the next step, where we can then key off the inode to
do one idempotent module load.

Let's do the obvious re-organization in one step, and then the new code
in another.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-06-28 15:46:43 -07:00
Masahiro Yamada
ddb5cdbafa kbuild: generate KSYMTAB entries by modpost
Commit 7b4537199a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.

For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().

The EXPORT_SYMBOL() compilation is split into two stages.

When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.

For example,

    EXPORT_SYMBOL(foo);
    EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);

will be encoded into the following assembly code:

    .section ".export_symbol","a"
    __export_symbol_foo:
            .asciz ""                      /* license */
            .asciz ""                      /* name space */
            .balign 8
            .quad foo                      /* symbol reference */
    .previous

    .section ".export_symbol","a"
    __export_symbol_bar:
            .asciz "GPL"                   /* license */
            .asciz "BAR_NAMESPACE"         /* name space */
            .balign 8
            .quad bar                      /* symbol reference */
    .previous

They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.

Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:

    KSYMTAB_FUNC(foo, "", "");
    KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");

KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.

With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.

[1] Deprecate EXPORT_DATA_SYMBOL()

In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.

Commit 22823ab419 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.

However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.

In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.

There are only two users of EXPORT_DATA_SYMBOL:

  EXPORT_DATA_SYMBOL_GPL(empty_zero_page)    (arch/ia64/kernel/head.S)
  EXPORT_DATA_SYMBOL(ia64_ivt)               (arch/ia64/kernel/ivt.S)

They are transformed as follows and output into .vmlinux.export.c

  KSYMTAB_DATA(empty_zero_page, "_gpl", "");
  KSYMTAB_DATA(ia64_ivt, "", "");

The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().

EXPORT_DATA_SYMBOL() is now deprecated.

[2] merge <linux/export.h> and <asm-generic/export.h>

There are two similar header implementations:

  include/linux/export.h        for .c files
  include/asm-generic/export.h  for .S files

Ideally, the functionality should be consistent between them, but they
tend to diverge.

Commit 8651ec01da ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.

This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.

<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.

They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.

[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.

We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2023-06-22 21:17:10 +09:00
Lucas De Marchi
fadb74f9f2 module/decompress: Fix error checking on zstd decompression
While implementing support for in-kernel decompression in kmod,
finit_module() was returning a very suspicious value:

	finit_module(3, "", MODULE_INIT_COMPRESSED_FILE) = 18446744072717407296

It turns out the check for module_get_next_page() failing is wrong,
and hence the decompression was not really taking place. Invert
the condition to fix it.

Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Cc: stable@kernel.org
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-06-01 14:36:46 -07:00
Song Liu
db3e33dd8b module: fix module load for ia64
Frank reported boot regression in ia64 as:

ELILO v3.16 for EFI/IA-64
..
Uncompressing Linux... done
Loading file AC100221.initrd.img...done
[    0.000000] Linux version 6.4.0-rc3 (root@x4270) (ia64-linux-gcc
(GCC) 12.2.0, GNU ld (GNU Binutils) 2.39) #1 SMP Thu May 25 15:52:20
CEST 2023
[    0.000000] efi: EFI v1.1 by HP
[    0.000000] efi: SALsystab=0x3ee7a000 ACPI 2.0=0x3fe2a000
ESI=0x3ee7b000 SMBIOS=0x3ee7c000 HCDP=0x3fe28000
[    0.000000] PCDP: v3 at 0x3fe28000
[    0.000000] earlycon: uart8250 at MMIO 0x00000000f4050000 (options
'9600n8')
[    0.000000] printk: bootconsole [uart8250] enabled
[    0.000000] ACPI: Early table checksum verification disabled
[    0.000000] ACPI: RSDP 0x000000003FE2A000 000028 (v02 HP    )
[    0.000000] ACPI: XSDT 0x000000003FE2A02C 0000CC (v01 HP     rx2620
00000000 HP   00000000)
[...]
[    3.793350] Run /init as init process
Loading, please wait...
Starting systemd-udevd version 252.6-1
[    3.951100] ------------[ cut here ]------------
[    3.951100] WARNING: CPU: 6 PID: 140 at kernel/module/main.c:1547
__layout_sections+0x370/0x3c0
[    3.949512] Unable to handle kernel paging request at virtual address
1000000000000000
[    3.951100] Modules linked in:
[    3.951100] CPU: 6 PID: 140 Comm: (udev-worker) Not tainted 6.4.0-rc3 #1
[    3.956161] (udev-worker)[142]: Oops 11003706212352 [1]
[    3.951774] Hardware name: hp server rx2620                   , BIOS
04.29
11/30/2007
[    3.951774]
[    3.951774] Call Trace:
[    3.958339] Unable to handle kernel paging request at virtual address
1000000000000000
[    3.956161] Modules linked in:
[    3.951774]  [<a0000001000156d0>] show_stack.part.0+0x30/0x60
[    3.951774]                                 sp=e000000183a67b20
bsp=e000000183a61628
[    3.956161]
[    3.956161]

which bisect to module_memory change [1].

Debug showed that ia64 uses some special sections:

__layout_sections: section .got (sh_flags 10000002) matched to MOD_INVALID
__layout_sections: section .sdata (sh_flags 10000003) matched to MOD_INVALID
__layout_sections: section .sbss (sh_flags 10000003) matched to MOD_INVALID

All these sections are loaded to module core memory before [1].

Fix ia64 boot by loading these sections to MOD_DATA (core rw data).

[1] commit ac3b432839 ("module: replace module_layout with module_memory")

Fixes: ac3b432839 ("module: replace module_layout with module_memory")
Reported-by: Frank Scheiner <frank.scheiner@web.de>
Closes: https://lists.debian.org/debian-ia64/2023/05/msg00010.html
Closes: https://marc.info/?l=linux-ia64&m=168509859125505
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Song Liu <song@kernel.org>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-05-30 09:29:40 -07:00
Maninder Singh
4f521bab5b kallsyms: remove unsed API lookup_symbol_attrs
with commit '7878c231dae0 ("slab: remove /proc/slab_allocators")'
lookup_symbol_attrs usage is removed.

Thus removing redundant API.

Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-05-26 15:10:18 -07:00
Sebastian Andrzej Siewior
cb0b50b813 module: Remove preempt_disable() from module reference counting.
The preempt_disable() section in module_put() was added in commit
   e1783a240f ("module: Use this_cpu_xx to dynamically allocate counters")

while the per-CPU counter were switched to another API. The API requires
that during the RMW operation the CPU remained the same.

This counting API was later replaced with atomic_t in commit
   2f35c41f58 ("module: Replace module_ref with atomic_t refcnt")

Since this atomic_t replacement there is no need to keep preemption
disabled while the reference counter is modified.

Remove preempt_disable() from module_put(), __module_get() and
try_module_get().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-05-23 22:23:18 -07:00
Harshit Mogalapalli
d36f6efbe0 module: Fix use-after-free bug in read_file_mod_stats()
Smatch warns:
	kernel/module/stats.c:394 read_file_mod_stats()
	warn: passing freed memory 'buf'

We are passing 'buf' to simple_read_from_buffer() after freeing it.

Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'.

Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-05-22 14:13:13 -07:00
Arnd Bergmann
0b891c83d8 module: include internal.h in module/dups.c
Two newly introduced functions are declared in a header that is not
included before the definition, causing a warning with sparse or
'make W=1':

kernel/module/dups.c:118:6: error: no previous prototype for 'kmod_dup_request_exists_wait' [-Werror=missing-prototypes]
  118 | bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/module/dups.c:220:6: error: no previous prototype for 'kmod_dup_request_announce' [-Werror=missing-prototypes]
  220 | void kmod_dup_request_announce(char *module_name, int ret)
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~

Add an explicit include to ensure the prototypes match.

Fixes: 8660484ed1 ("module: add debugging auto-load duplicate module support")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304141440.DYO4NAzp-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-05-02 20:33:36 -07:00