kernel/linux.git/drivers/firmware/efi, branch v4.14.263

efi: Change down_interruptible() in virt_efi_reset_system() to down_trylock()

2021-10-20T08:42:03+00:00

commit 38fa3206bf441911258e5001ac8b6738693f8d82 upstream. While reboot the system by sysrq, the following bug will be occur. BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:90 in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 10052, name: rc.shutdown CPU: 3 PID: 10052 Comm: rc.shutdown Tainted: G W O 5.10.0 #1 Call trace: dump_backtrace+0x0/0x1c8 show_stack+0x18/0x28 dump_stack+0xd0/0x110 ___might_sleep+0x14c/0x160 __might_sleep+0x74/0x88 down_interruptible+0x40/0x118 virt_efi_reset_system+0x3c/0xd0 efi_reboot+0xd4/0x11c machine_restart+0x60/0x9c emergency_restart+0x1c/0x2c sysrq_handle_reboot+0x1c/0x2c __handle_sysrq+0xd0/0x194 write_sysrq_trigger+0xbc/0xe4 proc_reg_write+0xd4/0xf0 vfs_write+0xa8/0x148 ksys_write+0x6c/0xd8 __arm64_sys_write+0x18/0x28 el0_svc_common.constprop.3+0xe4/0x16c do_el0_svc+0x1c/0x2c el0_svc+0x20/0x30 el0_sync_handler+0x80/0x17c el0_sync+0x158/0x180 The reason for this problem is that irq has been disabled in machine_restart() and then it calls down_interruptible() in virt_efi_reset_system(), which would occur sleep in irq context, it is dangerous! Commit 99409b935c9a("locking/semaphore: Add might_sleep() to down_*() family") add might_sleep() in down_interruptible(), so the bug info is here. down_trylock() can solve this problem, cause there is no might_sleep. -------- Cc: Signed-off-by: Zhang Jianhua Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi/cper: use stack buffer for error record decoding

2021-10-20T08:42:03+00:00

commit b3a72ca80351917cc23f9e24c35f3c3979d3c121 upstream. Joe reports that using a statically allocated buffer for converting CPER error records into human readable text is probably a bad idea. Even though we are not aware of any actual issues, a stack buffer is clearly a better choice here anyway, so let's move the buffer into the stack frames of the two functions that refer to it. Cc: Reported-by: Joe Perches Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: cper: fix snprintf() use in cper_dimm_err_location()

2021-06-10T10:43:49+00:00

[ Upstream commit 942859d969de7f6f7f2659a79237a758b42782da ] snprintf() should be given the full buffer size, not one less. And it guarantees nul-termination, so doing it manually afterwards is pointless. It's even potentially harmful (though probably not in practice because CPER_REC_LEN is 256), due to the "return how much would have been written had the buffer been big enough" semantics. I.e., if the bank and/or device strings are long enough that the "DIMM location ..." output gets truncated, writing to msg[n] is a buffer overflow. Signed-off-by: Rasmus Villemoes Fixes: 3760cd20402d4 ("CPER: Adjust code flow of some functions") Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efi: Allow EFI_MEMORY_XP and EFI_MEMORY_RO both to be cleared

2021-06-10T10:43:49+00:00

[ Upstream commit 45add3cc99feaaf57d4b6f01d52d532c16a1caee ] UEFI spec 2.9, p.108, table 4-1 lists the scenario that both attributes are cleared with the description "No memory access protection is possible for Entry". So we can have valid entries where both attributes are cleared, so remove the check. Signed-off-by: Heiner Kallweit Fixes: 10f0d2f577053 ("efi: Implement generic support for the Memory Attributes table") Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efi: Make it possible to disable efivar_ssdt entirely

2020-07-09T07:36:33+00:00

commit 435d1a471598752446a72ad1201b3c980526d869 upstream. In most cases, such as CONFIG_ACPI_CUSTOM_DSDT and CONFIG_ACPI_TABLE_UPGRADE, boot-time modifications to firmware tables are tied to specific Kconfig options. Currently this is not the case for modifying the ACPI SSDT via the efivar_ssdt kernel command line option and associated EFI variable. This patch adds CONFIG_EFI_CUSTOM_SSDT_OVERLAYS, which defaults disabled, in order to allow enabling or disabling that feature during the build. Cc: Signed-off-by: Peter Jones Link: https://lore.kernel.org/r/20200615202408.2242614-1-pjones@redhat.com Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi/esrt: Fix reference count leak in esre_create_sysfs_entry.

2020-06-30T19:38:03+00:00

[ Upstream commit 4ddf4739be6e375116c375f0a68bf3893ffcee21 ] kobject_init_and_add() takes reference even when it fails. If this function returns an error, kobject_put() must be called to properly clean up the memory associated with the object. Previous commit "b8eb718348b8" fixed a similar problem. Fixes: 0bb549052d33 ("efi: Add esrt support") Signed-off-by: Qiushi Wu Link: https://lore.kernel.org/r/20200528183804.4497-1-wu000273@umn.edu Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

efi/efivars: Add missing kobject_put() in sysfs entry creation error path

2020-06-20T08:25:00+00:00

commit d8bd8c6e2cfab8b78b537715255be8d7557791c0 upstream. The documentation provided by kobject_init_and_add() clearly spells out the need to call kobject_put() on the kobject if an error is returned. Add this missing call to the error path. Cc: Reported-by: 亿一 Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi/x86: Ignore the memory attributes table on i386

2020-04-24T06:00:28+00:00

[ Upstream commit dd09fad9d2caad2325a39b766ce9e79cfc690184 ] Commit: 3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures") moved the call to efi_memattr_init() from ARM specific to the generic EFI init code, in order to be able to apply the restricted permissions described in that table on x86 as well. We never enabled this feature fully on i386, and so mapping and reserving this table is pointless. However, due to the early call to memblock_reserve(), the memory bookkeeping gets confused to the point where it produces the splat below when we try to map the memory later on: ------------[ cut here ]------------ ioremap on RAM at 0x3f251000 - 0x3fa1afff WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ... Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 EIP: __ioremap_caller.constprop.0+0x249/0x260 Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ... EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001 ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296 CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690 Call Trace: ioremap_cache+0xd/0x10 ? old_map_region+0x72/0x9d old_map_region+0x72/0x9d efi_map_region+0x8/0xa efi_enter_virtual_mode+0x260/0x43b start_kernel+0x329/0x3aa i386_start_kernel+0xa7/0xab startup_32_smp+0x164/0x168 ---[ end trace e15ccf6b9f356833 ]--- Let's work around this by disregarding the memory attributes table altogether on i386, which does not result in a loss of functionality or protection, given that we never consumed the contents. Fixes: 3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ") Tested-by: Arvind Sankar Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@kernel.org Signed-off-by: Sasha Levin

efi: Add a sanity check to efivar_store_raw()

2020-03-20T09:54:20+00:00

commit d6c066fda90d578aacdf19771a027ed484a79825 upstream. Add a sanity check to efivar_store_raw() the same way efivar_{attr,size,data}_read() and efivar_show_raw() have it. Signed-off-by: Vladis Dronov Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Cc: Link: https://lore.kernel.org/r/20200305084041.24053-3-vdronov@redhat.com Link: https://lore.kernel.org/r/20200308080859.21568-25-ardb@kernel.org Signed-off-by: Greg Kroah-Hartman

efi: Fix a race and a buffer overflow while reading efivars via sysfs

2020-03-20T09:54:17+00:00

commit 286d3250c9d6437340203fb64938bea344729a0e upstream. There is a race and a buffer overflow corrupting a kernel memory while reading an EFI variable with a size more than 1024 bytes via the older sysfs method. This happens because accessing struct efi_variable in efivar_{attr,size,data}_read() and friends is not protected from a concurrent access leading to a kernel memory corruption and, at best, to a crash. The race scenario is the following: CPU0: CPU1: efivar_attr_read() var->DataSize = 1024; efivar_entry_get(... &var->DataSize) down_interruptible(&efivars_lock) efivar_attr_read() // same EFI var var->DataSize = 1024; efivar_entry_get(... &var->DataSize) down_interruptible(&efivars_lock) virt_efi_get_variable() // returns EFI_BUFFER_TOO_SMALL but // var->DataSize is set to a real // var size more than 1024 bytes up(&efivars_lock) virt_efi_get_variable() // called with var->DataSize set // to a real var size, returns // successfully and overwrites // a 1024-bytes kernel buffer up(&efivars_lock) This can be reproduced by concurrent reading of an EFI variable which size is more than 1024 bytes: ts# for cpu in $(seq 0 $(nproc --ignore=1)); do ( taskset -c $cpu \ cat /sys/firmware/efi/vars/KEKDefault*/size & ) ; done Fix this by using a local variable for a var's data buffer size so it does not get overwritten. Fixes: e14ab23dde12b80d ("efivars: efivar_entry API") Reported-by: Bob Sanders and the LTP testsuite Signed-off-by: Vladis Dronov Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Cc: Link: https://lore.kernel.org/r/20200305084041.24053-2-vdronov@redhat.com Link: https://lore.kernel.org/r/20200308080859.21568-24-ardb@kernel.org Signed-off-by: Greg Kroah-Hartman