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path: root/lib/efi_loader/efi_var_mem.c
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2025-02-20efi_loader: remove comparisons to string literals from runtimeIlias Apalodimas
For EFI runtime services, we manage to preserve string literals by placing the .efi_runtime section just before .data and preserving it when marking the runtime memory by marking surrounding boottime code as runtime. This is ok for now but will break if we update any linker scripts and decouple .text and .runtime sections. So let's define the strings we used to compare in the appropriate section for runtime services Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
2025-01-26efi_loader: use LOGC_EFI consistentlyHeinrich Schuchardt
The log category should be LOGC_EFI all over the EFI sub-system. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2024-05-01efi_loader: address coverity report 492766 for dead codeIlias Apalodimas
The check of the return code is already done a few lines above. Although it doesn't cause any functional issues, remove the superfluous checks Addresses-Coverity-ID: 492766 Control flow issues (DEADCODE) Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2024-04-20efi_loader: add an EFI variable with the file contentsIlias Apalodimas
Previous patches enabled SetVariableRT using a RAM backend. Although EBBR [0] defines a variable format we can teach userspace tools and write the altered variables, it's better if we skip the ABI requirements completely. So let's add a new variable, in its own namespace called "VarToFile" which contains a binary dump of the updated RT, BS and, NV variables and will be updated when GetVariable is called. Some adjustments are needed to do that. Currently we discard BS-only variables in EBS(). We need to preserve those on the RAM backend that exposes the variables. Since BS-only variables can't appear at runtime we need to move the memory masking checks from efi_var_collect() to efi_get_next_variable_name_mem()/ efi_get_variable_mem() and do the filtering at runtime. We also need an efi_var_collect() variant available at runtime, in order to construct the "VarToFile" buffer on the fly. All users and applications (for linux) have to do when updating a variable is dd that variable in the file described by "RTStorageVolatile". Linux efivarfs uses a first 4 bytes of the output to represent attributes in little-endian format. So, storing variables works like this: $~ efibootmgr -n 0001 $~ dd if=/sys/firmware/efi/efivars/VarToFile-b2ac5fc9-92b7-4acd-aeac-11e818c3130c of=/boot/efi/ubootefi.var skip=4 bs=1 [0] https://arm-software.github.io/ebbr/index.html#document-chapter5-variable-storage Suggested-by: Ard Biesheuvel <ardb@kernel.org> # dumping all variables to a variable Co-developed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> # contributed on efi_var_collect_mem() Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2023-12-21efi_loader: Remove <common.h>Tom Rini
We largely do not need <common.h> in these files, so drop it. The only exception here is that efi_freestanding.c needs <linux/types.h> and had been getting that via <common.h>. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Rini <trini@konsulko.com>
2023-07-09efi_loader: Avoid underflow when calculating remaining var store sizeAlper Nebi Yasak
The efi_var_mem_free() function calculates the available size for a new EFI variable by subtracting the occupied buffer size and the overhead for a new variable from the maximum buffer size set in Kconfig. This is then returned as QueryVariableInfo()'s RemainingVariableStorageSize output. This can underflow as the calculation is done in and processed as unsigned integer types. Check for underflow before doing the subtraction and return zero if there's no space. Fixes: f1f990a8c958 ("efi_loader: memory buffer for variables") Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2023-02-19efi_loader: avoid buffer overrun in efi_var_mem_compareHeinrich Schuchardt
We should not scan beyond the end of string name. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2022-12-29efi_loader: use u16_strlen() in efi_var_mem_ins()Heinrich Schuchardt
Don't duplicate library functionality. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2022-12-20efi_loader: fix efi_get_next_variable_name_mem()Heinrich Schuchardt
The VariableNameSize parameter is in bytes but u16_strnlen() counts u16. Fix the parameter check for null termination. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2021-10-25efi_loader: treat UEFI variable name as constHeinrich Schuchardt
UEFI variable names are typically constants and hence should be defined as const. Unfortunately some of our API functions do not define the parameters for UEFI variable names as const. This requires unnecessary conversions. Adjust parameters of several internal functions to tre UEFI variable names as const. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2021-01-20efi_loader: Avoid emitting efi_var_buf to .GOTIlias Apalodimas
Atish reports that on RISC-V, accessing the EFI variables causes a kernel panic. An objdump of the file verifies that, since the global pointer for efi_var_buf ends up in .GOT section which is not mapped in virtual address space for Linux. <snip of efi_var_mem_find> 0000000000000084 <efi_var_mem_find>: 84: 715d addi sp,sp,-80 * objdump -dr 0000000000000086 <.LCFI2>: 86: e0a2 sd s0,64(sp) 88: fc26 sd s1,56(sp) 8a: e486 sd ra,72(sp) 8c: f84a sd s2,48(sp) 8e: f44e sd s3,40(sp) 90: f052 sd s4,32(sp) 92: ec56 sd s5,24(sp) 94: 00000497 auipc s1,0x0 94: R_RISCV_GOT_HI20 efi_var_buf 98: 0004b483 ld s1,0(s1) # 94 <.LCFI2+0xe> 98: R_RISCV_PCREL_LO12_I .L0 98: R_RISCV_RELAX *ABS* * objdump -t 0000000000000084 g F .text.efi_runtime 00000000000000b8 efi_var_mem_find With the patch applied: * objdump -dr 0000000000000086 <.LCFI2>: 86: e0a2 sd s0,64(sp) 88: fc26 sd s1,56(sp) 8a: e486 sd ra,72(sp) 8c: f84a sd s2,48(sp) 8e: f44e sd s3,40(sp) 90: f052 sd s4,32(sp) 92: ec56 sd s5,24(sp) 94: 00000497 auipc s1,0x0 94: R_RISCV_PCREL_HI20 .LANCHOR0 94: R_RISCV_RELAX *ABS* 98: 00048493 mv s1,s1 98: R_RISCV_PCREL_LO12_I .L0 98: R_RISCV_RELAX *ABS* * objdump -t 0000000000000008 l O .data.efi_runtime 0000000000000008 efi_var_buf On arm64 this works, because there's no .GOT entries for this and everything is converted to relative references. * objdump -dr (identical pre-post patch, only the new function shows up) 00000000000000b4 <efi_var_mem_find>: b4: aa0003ee mov x14, x0 b8: 9000000a adrp x10, 0 <efi_var_mem_compare> b8: R_AARCH64_ADR_PREL_PG_HI21 .data.efi_runtime bc: 91000140 add x0, x10, #0x0 bc: R_AARCH64_ADD_ABS_LO12_NC .data.efi_runtime c0: aa0103ed mov x13, x1 c4: 79400021 ldrh w1, [x1] c8: aa0203eb mov x11, x2 cc: f9400400 ldr x0, [x0, #8] d0: b940100c ldr w12, [x0, #16] d4: 8b0c000c add x12, x0, x12 So let's switch efi_var_buf to static and create a helper function for anyone that needs to update it. Fixes: e01aed47d6a0 ("efi_loader: Enable run-time variable support for tee based variables") Reported-by: Atish Patra <atishp@atishpatra.org> Tested-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-11-21efi_loader: parameter check in GetNextVariableName()Heinrich Schuchardt
If GetNextVariableName() is called with a non-existing combination of VariableName and VendorGuid, return EFI_INVALID_PARAMETER. If GetNextVariableName() is called with a string that is not zero terminated, return EFI_INVALID_PARAMETER. Reformat a line over 80 characters. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-09-14efi_loader: efi_var_mem_notify_exit_boot_servicesHeinrich Schuchardt
efi_var_mem_notify_exit_boot_services() is invoked when ExitBootServices() is called by the UEFI payload. efi_var_mem_notify_exit_boot_services() should not be defined as __efi_runtime as it is invoking EFI_ENTRY() and EFI_EXIT() which themselves are not __efi_runtime. Fixes: f1f990a8c958 ("efi_loader: memory buffer for variables") Fixes: e01aed47d6a0 ("efi_loader: Enable run-time variable support for tee based variables") Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2020-08-01efi_loader: Enable run-time variable support for tee based variablesIlias Apalodimas
We recently added functions for storing/restoring variables from a file to a memory backed buffer marked as __efi_runtime_data commit f1f990a8c958 ("efi_loader: memory buffer for variables") commit 5f7dcf079de8 ("efi_loader: UEFI variable persistence") Using the same idea we now can support GetVariable() and GetNextVariable() on the OP-TEE based variables as well. So let's re-arrange the code a bit and move the commmon code for accessing variables out of efi_variable.c. Create common functions for reading variables from memory that both implementations can use on run-time. Then just use those functions in the run-time variants of the OP-TEE based EFI variable implementation and initialize the memory buffer on ExitBootServices() Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-22efi_loader: don't use memmove() in efi_var_mem_del()Heinrich Schuchardt
efi_var_mem_del() is in __efi_runtime because it would be needed for a runtime implementation of SetVariable(). memmove() is not in __efi_runtime. So we should not use it in efi_var_mem_del(). Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-22efi_loader: efi_current_var after SetVirtualAddressMapHeinrich Schuchardt
Variable efi_current_var is a pointer to a physical memory address that becomes invalid after SetVirtualAddressMap(). Instead of converting it via ConvertPointer() simply set it to NULL. Fixes: b02a707152dc ("efi_loader: enable UEFI variables at runtime") Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-11efi_loader: memory buffer for variablesHeinrich Schuchardt
Saving UEFI variable as encoded U-Boot environment variables does not allow support at runtime. Provide functions to manage a memory buffer with UEFI variables. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>