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path: root/include/efi_variable.h
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2021-10-25efi_loader: function to get GUID for variable nameHeinrich Schuchardt
In multiple places we need the default GUID matching a variable name. The patch provides a library function. For secure boot related variables like 'PK', 'KEK', 'db' a lookup table is used. For all other variable names EFI_GLOBAL_VARIABLE is returned. 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>
2021-09-04efi_loader: efi_auth_var_type for AuditMode, DeployedModeHeinrich Schuchardt
Writing variables AuditMode and DeployedMode serves to switch between Secure Boot modes. Provide a separate value for these in efi_auth_var_type. With this patch the variables will not be read from from file even if they are marked as non-volatile by mistake. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
2021-09-04efi_loader: don't load signature database from fileHeinrich Schuchardt
The UEFI specification requires that the signature database may only be stored in tamper-resistant storage. So these variable may not be read from an unsigned file. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
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>
2020-12-20efi_loader: make variable store size customizableHeinrich Schuchardt
Currently the size of the buffer to keep UEFI variables in memory is fixed at 16384 bytes. This size has proven to be too small for some use cases. Make the size of the memory buffer for UEFI variables customizable. Reported-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
2020-08-24efi_loader: remove empty comment lineHeinrich Schuchardt
Remove a line leading to a warning in make htmldocs. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
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>
2020-07-16efi_loader: describe EFI_VAR_FILE_MAGICHeinrich Schuchardt
Add documentation for EFI_VAR_FILE_MAGIC used in the file format for UEFI variables. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-16efi_loader: pre-seed UEFI variablesHeinrich Schuchardt
Include a file with the initial values for non-volatile UEFI variables into the U-Boot binary. If this variable is set, changes to variable PK will not be allowed. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-16efi_loader: identify PK, KEK, db, dbx correctlyHeinrich Schuchardt
To determine if a varible is on the of the authentication variables PK, KEK, db, dbx we have to check both the name and the GUID. Provide a function converting the variable-name/guid pair to an enum and use it consistently. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-16efi_loader: restructure code for TEE variablesHeinrich Schuchardt
When using secure boot functions needed both for file and TEE based UEFI variables have to be moved to the common code module efi_var_common.c. 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>
2020-07-11efi_loader: UEFI variable persistenceHeinrich Schuchardt
Persist non-volatile UEFI variables in a file on the EFI system partition. The file is written whenever a non-volatile UEFI variable is changed after initialization of the UEFI sub-system. The file is read during the UEFI sub-system initialization to restore non-volatile UEFI variables. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-11efi_loader: separate UEFI variable API from implemementationHeinrich Schuchardt
Separate the remaining UEFI variable API functions GetNextVariableName and QueryVariableInfo() from internal functions implementing them. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-07-11efi_loader: prepare for read only OP-TEE variablesHeinrich Schuchardt
We currently have two implementations of UEFI variables: * variables provided via an OP-TEE module * variables stored in the U-Boot environment Read only variables are up to now only implemented in the U-Boot environment implementation. Provide a common interface for both implementations that allows handling read-only variables. As variable access is limited to very few source files put variable related definitions into new include efi_variable.h instead of efi_loader. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>