user/sven/linux.git/kernel/module.c, branch v5.4.279

modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules

2023-09-23T08:59:36Z

commit 9011e49d54dcc7653ebb8a1e05b5badb5ecfa9f9 upstream. It has recently come to my attention that nvidia is circumventing the protection added in 262e6ae7081d ("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: 262e6ae7081d ("modules: inherit TAINT_PROPRIETARY_MODULE") Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain Signed-off-by: Greg Kroah-Hartman

module: Don't wait for GOING modules

2023-02-06T06:52:43Z

commit 0254127ab977e70798707a7a2b757c9f3c971210 upstream. During a system boot, it can happen that the kernel receives a burst of requests to insert the same module but loading it eventually fails during its init call. For instance, udev can make a request to insert a frequency module for each individual CPU when another frequency module is already loaded which causes the init function of the new module to return an error. Since commit 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading"), the kernel waits for modules in MODULE_STATE_GOING state to finish unloading before making another attempt to load the same module. This creates unnecessary work in the described scenario and delays the boot. In the worst case, it can prevent udev from loading drivers for other devices and might cause timeouts of services waiting on them and subsequently a failed boot. This patch attempts a different solution for the problem 6e6de3dee51a was trying to solve. Rather than waiting for the unloading to complete, it returns a different error code (-EBUSY) for modules in the GOING state. This should avoid the error situation that was described in 6e6de3dee51a (user space attempting to load a dependent module because the -EEXIST error code would suggest to user space that the first module had been loaded successfully), while avoiding the delay situation too. This has been tested on linux-next since December 2022 and passes all kmod selftests except test 0009 with module compression enabled but it has been confirmed that this issue has existed and has gone unnoticed since prior to this commit and can also be reproduced without module compression with a simple usleep(5000000) on tools/modprobe.c [0]. These failures are caused by hitting the kernel mod_concurrent_max and can happen either due to a self inflicted kernel module auto-loead DoS somehow or on a system with large CPU count and each CPU count incorrectly triggering many module auto-loads. Both of those issues need to be fixed in-kernel. [0] https://lore.kernel.org/all/Y9A4fiobL6IHp%2F%2FP@bombadil.infradead.org/ Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Co-developed-by: Martin Wilck Signed-off-by: Martin Wilck Signed-off-by: Petr Pavlu Cc: stable@vger.kernel.org Reviewed-by: Petr Mladek [mcgrof: enhance commit log with testing and kmod test result interpretation ] Signed-off-by: Luis Chamberlain Signed-off-by: Greg Kroah-Hartman

module/ftrace: handle patchable-function-entry

2022-02-23T10:59:56Z

commit a1326b17ac03a9012cb3d01e434aacb4d67a416c upstream. When using patchable-function-entry, the compiler will record the callsites into a section named "__patchable_function_entries" rather than "__mcount_loc". Let's abstract this difference behind a new FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this explicitly (e.g. with custom module linker scripts). As parisc currently handles this explicitly, it is fixed up accordingly, with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is only defined when DYNAMIC_FTRACE is selected, the parisc module loading code is updated to only use the definition in that case. When DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so this removes some redundant work in that case. To make sure that this is keep up-to-date for modules and the main kernel, a comment is added to vmlinux.lds.h, with the existing ifdeffery simplified for legibility. I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled, and verified that the section made it into the .ko files for modules. Signed-off-by: Mark Rutland Acked-by: Helge Deller Acked-by: Steven Rostedt (VMware) Reviewed-by: Ard Biesheuvel Reviewed-by: Torsten Duwe Tested-by: Amit Daniel Kachhap Tested-by: Sven Schnelle Tested-by: Torsten Duwe Cc: Ingo Molnar Cc: James E.J. Bottomley Cc: Jessica Yu Cc: linux-parisc@vger.kernel.org Cc: Stephen Boyd Signed-off-by: Greg Kroah-Hartman

Revert "module, async: async_synchronize_full() on module init iff async is used"

2022-02-23T10:59:56Z

[ Upstream commit 67d6212afda218d564890d1674bab28e8612170f ] This reverts commit 774a1221e862b343388347bac9b318767336b20b. We need to finish all async code before the module init sequence is done. In the reverted commit the PF_USED_ASYNC flag was added to mark a thread that called async_schedule(). Then the PF_USED_ASYNC flag was used to determine whether or not async_synchronize_full() needs to be invoked. This works when modprobe thread is calling async_schedule(), but it does not work if module dispatches init code to a worker thread which then calls async_schedule(). For example, PCI driver probing is invoked from a worker thread based on a node where device is attached: if (cpu < nr_cpu_ids) error = work_on_cpu(cpu, local_pci_probe, &ddi); else error = local_pci_probe(&ddi); We end up in a situation where a worker thread gets the PF_USED_ASYNC flag set instead of the modprobe thread. As a result, async_synchronize_full() is not invoked and modprobe completes without waiting for the async code to finish. The issue was discovered while loading the pm80xx driver: (scsi_mod.scan=async) modprobe pm80xx worker ... do_init_module() ... pci_call_probe() work_on_cpu(local_pci_probe) local_pci_probe() pm8001_pci_probe() scsi_scan_host() async_schedule() worker->flags |= PF_USED_ASYNC; ... < return from worker > ... if (current->flags & PF_USED_ASYNC) <--- false async_synchronize_full(); Commit 21c3c5d28007 ("block: don't request module during elevator init") fixed the deadlock issue which the reverted commit 774a1221e862 ("module, async: async_synchronize_full() on module init iff async is used") tried to fix. Since commit 0fdff3ec6d87 ("async, kmod: warn on synchronous request_module() from async workers") synchronous module loading from async is not allowed. Given that the original deadlock issue is fixed and it is no longer allowed to call synchronous request_module() from async we can remove PF_USED_ASYNC flag to make module init consistently invoke async_synchronize_full() unless async module probe is requested. Signed-off-by: Igor Pylypiv Reviewed-by: Changyuan Lyu Reviewed-by: Luis Chamberlain Acked-by: Tejun Heo Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

module: limit enabling module.sig_enforce

2021-06-30T12:47:42Z

[ Upstream commit 0c18f29aae7ce3dadd26d8ee3505d07cc982df75 ] Irrespective as to whether CONFIG_MODULE_SIG is configured, specifying "module.sig_enforce=1" on the boot command line sets "sig_enforce". Only allow "sig_enforce" to be set when CONFIG_MODULE_SIG is configured. This patch makes the presence of /sys/module/module/parameters/sig_enforce dependent on CONFIG_MODULE_SIG=y. Fixes: fda784e50aac ("module: export module signature enforcement status") Reported-by: Nayna Jain Tested-by: Mimi Zohar Tested-by: Jessica Yu Signed-off-by: Mimi Zohar Signed-off-by: Jessica Yu Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

modules: inherit TAINT_PROPRIETARY_MODULE

2021-05-11T12:04:04Z

commit 262e6ae7081df304fc625cf368d5c2cbba2bb991 upstream. If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag for all modules importing these symbols, and don't allow loading symbols from TAINT_PROPRIETARY_MODULE modules if the module previously imported gplonly symbols. Add a anti-circumvention devices so people don't accidentally get themselves into trouble this way. Comment from Greg: "Ah, the proven-to-be-illegal "GPL Condom" defense :)" [jeyu: pr_info -> pr_err and pr_warn as per discussion] Link: http://lore.kernel.org/r/20200730162957.GA22469@lst.de Acked-by: Daniel Vetter Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Greg Kroah-Hartman

modules: return licensing information from find_symbol

2021-05-11T12:04:04Z

commit ef1dac6021cc8ec5de02ce31722bf26ac4ed5523 upstream. Report the GPLONLY status through a new argument. Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Greg Kroah-Hartman

modules: rename the licence field in struct symsearch to license

2021-05-11T12:04:04Z

commit cd8732cdcc37d7077c4fa2c966b748c0662b607e upstream. Use the same spelling variant as the rest of the file. Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Greg Kroah-Hartman

modules: unexport __module_address

2021-05-11T12:04:03Z

commit 34e64705ad415ed7a816e60ef62b42fe6d1729d9 upstream. __module_address is only used by built-in code. Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Greg Kroah-Hartman

modules: unexport __module_text_address

2021-05-11T12:04:03Z

commit 3fe1e56d0e68b623dd62d8d38265d2a052e7e185 upstream. __module_text_address is only used by built-in code. Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Greg Kroah-Hartman