The kernel/kmod.c is already only built if we enabled modules, so
just stuff it under kernel/module/kmod.c and unify the MAINTAINERS
file for it.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The setup_load_info() was actually had ELF validation checks of its
own. To later cache useful variables as an secondary step just means
looping again over the ELF sections we just validated. We can simply
keep tabs of the key sections of interest as we validate the module
ELF section in one swoop, so do that and merge the two routines
together.
Expand a bit on the documentation / intent / goals.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The integrity of the struct module we load is important, and although
our ELF validator already checks that the module section must match
struct module, add a stop-gap check before we memcpy() the final minted
module. This also makes those inspecting the code what the goal is.
While at it, clarify the goal behind updating the sh_addr address.
The current comment is pretty misleading.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The ELF ".gnu.linkonce.this_module" section is special, it is what we
use to construct the struct module __this_module, which THIS_MODULE
points to. When userspace loads a module we always deal first with a
copy of the userspace buffer, and twiddle with the userspace copy's
version of the struct module. Eventually we allocate memory to do a
memcpy() of that struct module, under the assumption that the module
size is right. But we have no validity checks against the size or
the requirements for the section.
Add some validity checks for the special module section early and while
at it, cache the module section index early, so we don't have to do that
later.
While at it, just move over the assigment of the info->mod to make the
code clearer. The validity checker also adds an explicit size check to
ensure the module section size matches the kernel's run time size for
sizeof(struct module). This should prevent sloppy loads of modules
which are built today *without* actually increasing the size of
the struct module. A developer today can for example expand the size
of struct module, rebuild a directoroy 'make fs/xfs/' for example and
then try to insmode the driver there. That module would in effect have
an incorrect size. This new size check would put a stop gap against such
mistakes.
This also makes the entire goal of ".gnu.linkonce.this_module" pretty
clear. Before this patch verification of the goal / intent required some
Indian Jones whips, torches and cleaning up big old spider webs.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Converge on a compromise: so long as we have a module hit our linked
list of modules we taint. That is, the module was about to become live.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
It is silly to have taints spread out all over, we can just compromise
and add them if the module ever hit our linked list. Our sanity checkers
should just prevent crappy drivers / bogus ELF modules / etc and kconfig
options should be enough to let you *not* load things you don't want.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
check_modinfo() actually does two things:
a) sanity checks, some of which are fatal, and so we
prevent the user from completing trying to load a module
b) taints the kernel
The taints are pretty heavy handed because we're tainting the kernel
*before* we ever even get to load the module into the modules linked
list. That is, it it can fail for other reasons later as we review the
module's structure.
But this commit makes no functional changes, it just makes the intent
clearer and splits the code up where needed to make that happen.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The work to taint the kernel due to a module should be split
up eventually. To aid with this, split up the tainting on
check_modinfo_livepatch().
This let's us bring more early checks together which do return
a value, and makes changes easier to read later where we stuff
all the work to do the taints in one single routine.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The set_license() routine would seem to a reader to do some sort of
setting, but it does not. It just adds a taint if the license is
not set or proprietary.
This makes what the code is doing clearer, so much we can remove
the comment about it.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This moves check_modinfo() to early_mod_check(). This
doesn't make any functional changes either, as check_modinfo()
was the first call on layout_and_allocate(), so we're just
moving it back one routine and at the end.
This let's us keep separate the checkers from the allocator.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Move early sanity checkers for the module into a helper.
This let's us make it clear when we are working with the
local copy of the module prior to allocation.
This produces no functional changes, it just makes subsequent
changes easier to read.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Add a for_each_modinfo_entry() to make it easier to read and use.
This produces no functional changes but makes this code easiert
to read as we are used to with loops in the kernel and trims more
lines of code.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This makes it clearer what it is doing. While at it,
make it available to other code other than main.c.
This will be used in the subsequent patch and make
the changes easier to read.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Instead of forward declaring routines for get_modinfo() just move
everything up. This makes no functional changes.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Use kunmap_local() to unmap pages locally mapped with kmap_local_page().
kunmap_local() must be called on the kernel virtual address returned by
kmap_local_page(), differently from how we use kunmap() which instead
expects the mapped page as its argument.
In module_zstd_decompress() we currently map with kmap_local_page() and
unmap with kunmap(). This breaks the code and so it should be fixed.
Cc: Piotr Gorski <piotrgorski@cachyos.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Piotr Gorski <piotrgorski@cachyos.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Moving find_kallsyms_symbol_value from kernel/module/internal.h to
include/linux/module.h. The reason is that internal.h is not prepared to
be included when CONFIG_MODULES=n. find_kallsyms_symbol_value is used by
kernel/bpf/verifier.c and including internal.h from it (without modules)
leads into a compilation error:
In file included from ../include/linux/container_of.h:5,
from ../include/linux/list.h:5,
from ../include/linux/timer.h:5,
from ../include/linux/workqueue.h:9,
from ../include/linux/bpf.h:10,
from ../include/linux/bpf-cgroup.h:5,
from ../kernel/bpf/verifier.c:7:
../kernel/bpf/../module/internal.h: In function 'mod_find':
../include/linux/container_of.h:20:54: error: invalid use of undefined type 'struct module'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~
[...]
This patch fixes the above error.
Fixes: 31bf1dbccf ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/oe-kbuild-all/202303161404.OrmfCy09-lkp@intel.com/
Link: https://lore.kernel.org/bpf/20230317095601.386738-1-vmalik@redhat.com
This resolves two problems with attachment of fentry/fexit/fmod_ret/lsm
to functions located in modules:
1. The verifier tries to find the address to attach to in kallsyms. This
is always done by searching the entire kallsyms, not respecting the
module in which the function is located. Such approach causes an
incorrect attachment address to be computed if the function to attach
to is shadowed by a function of the same name located earlier in
kallsyms.
2. If the address to attach to is located in a module, the module
reference is only acquired in register_fentry. If the module is
unloaded between the place where the address is found
(bpf_check_attach_target in the verifier) and register_fentry, it is
possible that another module is loaded to the same address which may
lead to potential errors.
Since the attachment must contain the BTF of the program to attach to,
we extract the module from it and search for the function address in the
correct module (resolving problem no. 1). Then, the module reference is
taken directly in bpf_check_attach_target and stored in the bpf program
(in bpf_prog_aux). The reference is only released when the program is
unloaded (resolving problem no. 2).
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/3f6a9d8ae850532b5ef864ef16327b0f7a669063.1678432753.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Bring dynamic debug in line with other subsystems by using the module
notifier callbacks. This results in a net decrease in core module
code.
Additionally, Jim Cromie has a new dynamic debug classmap feature,
which requires that jump labels be initialized prior to dynamic debug.
Specifically, the new feature toggles a jump label from the existing
dynamic_debug_setup() function. However, this does not currently work
properly, because jump labels are initialized via the
'module_notify_list' notifier chain, which is invoked after the
current call to dynamic_debug_setup(). Thus, this patch ensures that
jump labels are initialized prior to dynamic debug by setting the
dynamic debug notifier priority to 0, while jump labels have the
higher priority of 1.
Tested by Jim using his new test case, and I've verfied the correct
printing via: # modprobe test_dynamic_debug dyndbg.
Link: https://lore.kernel.org/lkml/20230113193016.749791-21-jim.cromie@gmail.com/
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202302190427.9iIK2NfJ-lkp@intel.com/
Tested-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
CC: Jim Cromie <jim.cromie@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
The function within is defined in the main.c file, but not called
elsewhere, so remove this unused function.
This routine became no longer used after commit ("module: replace
module_layout with module_memory").
kernel/module/main.c:3007:19: warning: unused function 'within'.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4035
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
[mcgrof: adjust commit log to explain why this change is needed]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:
1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
obvious how these data are used (are they RO, RX, or RW?)
Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:
MOD_TEXT,
MOD_DATA,
MOD_RODATA,
MOD_RO_AFTER_INIT,
MOD_INIT_TEXT,
MOD_INIT_DATA,
MOD_INIT_RODATA,
and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.
Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.
module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.
Signed-off-by: Song Liu <song@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Luis Chamberlain
Fabio M. De FrancescoandLuis Chamberlain
Zhen LeiandLuis Chamberlain
Viktor MalikandDaniel Borkmann
Jason BaronandLuis Chamberlain
Jiapeng ChongandLuis Chamberlain
Song LiuandLuis Chamberlain
Alexey DobriyanandPetr Mladek