| Message ID | 20230329052926.69632-4-alexghiti@rivosinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | riscv: Introduce KASLR | expand |
On Tue, 28 Mar 2023 22:29:25 PDT (-0700), alexghiti@rivosinc.com wrote: > This prepares for riscv to use the same functions to handle the pĥysical > kernel move when KASLR is enabled. > > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> > --- > drivers/firmware/efi/libstub/arm64-stub.c | 111 +------------ This LGTM, but I'd prefer at least an Ack from either the Arm or EFI folks. I think that makes it too late for this merge window. > .../firmware/efi/libstub/efi-stub-helper.c | 151 ++++++++++++++++++ > drivers/firmware/efi/libstub/efistub.h | 8 + > 3 files changed, 167 insertions(+), 103 deletions(-) > > diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c > index d4a6b12a8741..b9e0d2cf09aa 100644 > --- a/drivers/firmware/efi/libstub/arm64-stub.c > +++ b/drivers/firmware/efi/libstub/arm64-stub.c > @@ -14,42 +14,6 @@ > > #include "efistub.h" > > -/* > - * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail > - * to provide space, and fail to zero it). Check for this condition by double > - * checking that the first and the last byte of the image are covered by the > - * same EFI memory map entry. > - */ > -static bool check_image_region(u64 base, u64 size) > -{ > - struct efi_boot_memmap *map; > - efi_status_t status; > - bool ret = false; > - int map_offset; > - > - status = efi_get_memory_map(&map, false); > - if (status != EFI_SUCCESS) > - return false; > - > - for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { > - efi_memory_desc_t *md = (void *)map->map + map_offset; > - u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; > - > - /* > - * Find the region that covers base, and return whether > - * it covers base+size bytes. > - */ > - if (base >= md->phys_addr && base < end) { > - ret = (base + size) <= end; > - break; > - } > - } > - > - efi_bs_call(free_pool, map); > - > - return ret; > -} > - > efi_status_t handle_kernel_image(unsigned long *image_addr, > unsigned long *image_size, > unsigned long *reserve_addr, > @@ -59,31 +23,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, > { > efi_status_t status; > unsigned long kernel_size, kernel_codesize, kernel_memsize; > - u32 phys_seed = 0; > - u64 min_kimg_align = efi_get_kimg_min_align(); > - > - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { > - efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; > - void *p; > - > - if (efi_nokaslr) { > - efi_info("KASLR disabled on kernel command line\n"); > - } else if (efi_bs_call(handle_protocol, image_handle, > - &li_fixed_proto, &p) == EFI_SUCCESS) { > - efi_info("Image placement fixed by loader\n"); > - } else { > - status = efi_get_random_bytes(sizeof(phys_seed), > - (u8 *)&phys_seed); > - if (status == EFI_NOT_FOUND) { > - efi_info("EFI_RNG_PROTOCOL unavailable\n"); > - efi_nokaslr = true; > - } else if (status != EFI_SUCCESS) { > - efi_err("efi_get_random_bytes() failed (0x%lx)\n", > - status); > - efi_nokaslr = true; > - } > - } > - } > > if (image->image_base != _text) > efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n"); > @@ -96,49 +35,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, > kernel_codesize = __inittext_end - _text; > kernel_memsize = kernel_size + (_end - _edata); > *reserve_size = kernel_memsize; > + *image_addr = (unsigned long)_text; > > - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { > - /* > - * If KASLR is enabled, and we have some randomness available, > - * locate the kernel at a randomized offset in physical memory. > - */ > - status = efi_random_alloc(*reserve_size, min_kimg_align, > - reserve_addr, phys_seed, > - EFI_LOADER_CODE); > - if (status != EFI_SUCCESS) > - efi_warn("efi_random_alloc() failed: 0x%lx\n", status); > - } else { > - status = EFI_OUT_OF_RESOURCES; > - } > - > - if (status != EFI_SUCCESS) { > - if (!check_image_region((u64)_text, kernel_memsize)) { > - efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); > - } else if (IS_ALIGNED((u64)_text, min_kimg_align) && > - (u64)_end < EFI_ALLOC_LIMIT) { > - /* > - * Just execute from wherever we were loaded by the > - * UEFI PE/COFF loader if the placement is suitable. > - */ > - *image_addr = (u64)_text; > - *reserve_size = 0; > - return EFI_SUCCESS; > - } > - > - status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, > - ULONG_MAX, min_kimg_align, > - EFI_LOADER_CODE); > - > - if (status != EFI_SUCCESS) { > - efi_err("Failed to relocate kernel\n"); > - *reserve_size = 0; > - return status; > - } > - } > - > - *image_addr = *reserve_addr; > - memcpy((void *)*image_addr, _text, kernel_size); > - caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); > + status = efi_kaslr_relocate_kernel(image_addr, > + reserve_addr, reserve_size, > + kernel_size, kernel_codesize, > + kernel_memsize, > + efi_kaslr_get_phys_seed(image_handle)); > + if (status != EFI_SUCCESS) > + return status; > > return EFI_SUCCESS; > } > diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c > index 1e0203d74691..40ac2625949c 100644 > --- a/drivers/firmware/efi/libstub/efi-stub-helper.c > +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c > @@ -718,3 +718,154 @@ void efi_remap_image(unsigned long image_base, unsigned alloc_size, > efi_warn("Failed to remap data region non-executable\n"); > } > } > + > +/** > + * efi_kaslr_get_phys_seed() - Get random seed for physical kernel KASLR > + * @image_handle: Handle to the image > + * > + * If KASLR is not disabled, obtain a random seed using EFI_RNG_PROTOCOL > + * that will be used to move the kernel physical mapping. > + * > + * Return: the random seed > + */ > +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle) > +{ > + efi_status_t status; > + u32 phys_seed; > + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; > + void *p; > + > + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) > + return 0; > + > + if (efi_nokaslr) { > + efi_info("KASLR disabled on kernel command line\n"); > + } else if (efi_bs_call(handle_protocol, image_handle, > + &li_fixed_proto, &p) == EFI_SUCCESS) { > + efi_info("Image placement fixed by loader\n"); > + } else { > + status = efi_get_random_bytes(sizeof(phys_seed), > + (u8 *)&phys_seed); > + if (status == EFI_SUCCESS) { > + return phys_seed; > + } else if (status == EFI_NOT_FOUND) { > + efi_info("EFI_RNG_PROTOCOL unavailable\n"); > + efi_nokaslr = true; > + } else if (status != EFI_SUCCESS) { > + efi_err("efi_get_random_bytes() failed (0x%lx)\n", > + status); > + efi_nokaslr = true; > + } > + } > + > + return 0; > +} > + > +/* > + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail > + * to provide space, and fail to zero it). Check for this condition by double > + * checking that the first and the last byte of the image are covered by the > + * same EFI memory map entry. > + */ > +static bool check_image_region(u64 base, u64 size) > +{ > + struct efi_boot_memmap *map; > + efi_status_t status; > + bool ret = false; > + int map_offset; > + > + status = efi_get_memory_map(&map, false); > + if (status != EFI_SUCCESS) > + return false; > + > + for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { > + efi_memory_desc_t *md = (void *)map->map + map_offset; > + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; > + > + /* > + * Find the region that covers base, and return whether > + * it covers base+size bytes. > + */ > + if (base >= md->phys_addr && base < end) { > + ret = (base + size) <= end; > + break; > + } > + } > + > + efi_bs_call(free_pool, map); > + > + return ret; > +} > + > +/** > + * efi_kaslr_relocate_kernel() - Relocate the kernel (random if KASLR enabled) > + * @image_addr: Pointer to the current kernel location > + * @reserve_addr: Pointer to the relocated kernel location > + * @reserve_size: Size of the relocated kernel > + * @kernel_size: Size of the text + data > + * @kernel_codesize: Size of the text > + * @kernel_memsize: Size of the text + data + bss > + * @phys_seed: Random seed used for the relocation > + * > + * If KASLR is not enabled, this function relocates the kernel to a fixed > + * address (or leave it as its current location). If KASLR is enabled, the > + * kernel physical location is randomized using the seed in parameter. > + * > + * Return: status code, EFI_SUCCESS if relocation is successful > + */ > +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, > + unsigned long *reserve_addr, > + unsigned long *reserve_size, > + unsigned long kernel_size, > + unsigned long kernel_codesize, > + unsigned long kernel_memsize, > + u32 phys_seed) > +{ > + efi_status_t status; > + u64 min_kimg_align = efi_get_kimg_min_align(); > + > + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { > + /* > + * If KASLR is enabled, and we have some randomness available, > + * locate the kernel at a randomized offset in physical memory. > + */ > + status = efi_random_alloc(*reserve_size, min_kimg_align, > + reserve_addr, phys_seed, > + EFI_LOADER_CODE); > + if (status != EFI_SUCCESS) > + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); > + } else { > + status = EFI_OUT_OF_RESOURCES; > + } > + > + if (status != EFI_SUCCESS) { > + if (!check_image_region(*image_addr, kernel_memsize)) { > + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); > + } else if (IS_ALIGNED(*image_addr, min_kimg_align) && > + (u64)_end < EFI_ALLOC_LIMIT) { > + /* > + * Just execute from wherever we were loaded by the > + * UEFI PE/COFF loader if the placement is suitable. > + */ > + *reserve_size = 0; > + return EFI_SUCCESS; > + } > + > + status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, > + ULONG_MAX, min_kimg_align, > + EFI_LOADER_CODE); > + > + if (status != EFI_SUCCESS) { > + efi_err("Failed to relocate kernel\n"); > + *reserve_size = 0; > + return status; > + } > + } > + > + memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); > + *image_addr = *reserve_addr; > + > + caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); > + > + return status; > +} > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h > index 6bd3bb86d967..64273371ce96 100644 > --- a/drivers/firmware/efi/libstub/efistub.h > +++ b/drivers/firmware/efi/libstub/efistub.h > @@ -1098,5 +1098,13 @@ const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize); > > void efi_remap_image(unsigned long image_base, unsigned alloc_size, > unsigned long code_size); > +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, > + unsigned long *reserve_addr, > + unsigned long *reserve_size, > + unsigned long kernel_size, > + unsigned long kernel_codesize, > + unsigned long kernel_memsize, > + u32 phys_seed); > +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); > > #endif
On 4/29/23 21:50, Palmer Dabbelt wrote: > On Tue, 28 Mar 2023 22:29:25 PDT (-0700), alexghiti@rivosinc.com wrote: >> This prepares for riscv to use the same functions to handle the pĥysical >> kernel move when KASLR is enabled. >> >> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> >> --- >> drivers/firmware/efi/libstub/arm64-stub.c | 111 +------------ > > This LGTM, but I'd prefer at least an Ack from either the Arm or EFI > folks. I think that makes it too late for this merge window. Note that I have a minor fix (RANDOMIZE_BASE should depend on 64BIT) and kernel test robot reported a few warnings and errors: ld: efi-stub-helper.c:undefined reference to `efi_icache_sync' efi-stub-helper.c:undefined reference to `efi_get_kimg_min_align' drivers/firmware/efi/libstub/efi-stub-helper.c:825:23: warning: implicit declaration of function 'efi_get_kimg_min_align' is invalid in C99 I'll wait for feedbacks and send a v3. Thanks, Alex > >> .../firmware/efi/libstub/efi-stub-helper.c | 151 ++++++++++++++++++ >> drivers/firmware/efi/libstub/efistub.h | 8 + >> 3 files changed, 167 insertions(+), 103 deletions(-) >> >> diff --git a/drivers/firmware/efi/libstub/arm64-stub.c >> b/drivers/firmware/efi/libstub/arm64-stub.c >> index d4a6b12a8741..b9e0d2cf09aa 100644 >> --- a/drivers/firmware/efi/libstub/arm64-stub.c >> +++ b/drivers/firmware/efi/libstub/arm64-stub.c >> @@ -14,42 +14,6 @@ >> >> #include "efistub.h" >> >> -/* >> - * Distro versions of GRUB may ignore the BSS allocation entirely >> (i.e., fail >> - * to provide space, and fail to zero it). Check for this condition >> by double >> - * checking that the first and the last byte of the image are >> covered by the >> - * same EFI memory map entry. >> - */ >> -static bool check_image_region(u64 base, u64 size) >> -{ >> - struct efi_boot_memmap *map; >> - efi_status_t status; >> - bool ret = false; >> - int map_offset; >> - >> - status = efi_get_memory_map(&map, false); >> - if (status != EFI_SUCCESS) >> - return false; >> - >> - for (map_offset = 0; map_offset < map->map_size; map_offset += >> map->desc_size) { >> - efi_memory_desc_t *md = (void *)map->map + map_offset; >> - u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; >> - >> - /* >> - * Find the region that covers base, and return whether >> - * it covers base+size bytes. >> - */ >> - if (base >= md->phys_addr && base < end) { >> - ret = (base + size) <= end; >> - break; >> - } >> - } >> - >> - efi_bs_call(free_pool, map); >> - >> - return ret; >> -} >> - >> efi_status_t handle_kernel_image(unsigned long *image_addr, >> unsigned long *image_size, >> unsigned long *reserve_addr, >> @@ -59,31 +23,6 @@ efi_status_t handle_kernel_image(unsigned long >> *image_addr, >> { >> efi_status_t status; >> unsigned long kernel_size, kernel_codesize, kernel_memsize; >> - u32 phys_seed = 0; >> - u64 min_kimg_align = efi_get_kimg_min_align(); >> - >> - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { >> - efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; >> - void *p; >> - >> - if (efi_nokaslr) { >> - efi_info("KASLR disabled on kernel command line\n"); >> - } else if (efi_bs_call(handle_protocol, image_handle, >> - &li_fixed_proto, &p) == EFI_SUCCESS) { >> - efi_info("Image placement fixed by loader\n"); >> - } else { >> - status = efi_get_random_bytes(sizeof(phys_seed), >> - (u8 *)&phys_seed); >> - if (status == EFI_NOT_FOUND) { >> - efi_info("EFI_RNG_PROTOCOL unavailable\n"); >> - efi_nokaslr = true; >> - } else if (status != EFI_SUCCESS) { >> - efi_err("efi_get_random_bytes() failed (0x%lx)\n", >> - status); >> - efi_nokaslr = true; >> - } >> - } >> - } >> >> if (image->image_base != _text) >> efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has >> bogus value\n"); >> @@ -96,49 +35,15 @@ efi_status_t handle_kernel_image(unsigned long >> *image_addr, >> kernel_codesize = __inittext_end - _text; >> kernel_memsize = kernel_size + (_end - _edata); >> *reserve_size = kernel_memsize; >> + *image_addr = (unsigned long)_text; >> >> - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { >> - /* >> - * If KASLR is enabled, and we have some randomness available, >> - * locate the kernel at a randomized offset in physical memory. >> - */ >> - status = efi_random_alloc(*reserve_size, min_kimg_align, >> - reserve_addr, phys_seed, >> - EFI_LOADER_CODE); >> - if (status != EFI_SUCCESS) >> - efi_warn("efi_random_alloc() failed: 0x%lx\n", status); >> - } else { >> - status = EFI_OUT_OF_RESOURCES; >> - } >> - >> - if (status != EFI_SUCCESS) { >> - if (!check_image_region((u64)_text, kernel_memsize)) { >> - efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI >> memory region\n"); >> - } else if (IS_ALIGNED((u64)_text, min_kimg_align) && >> - (u64)_end < EFI_ALLOC_LIMIT) { >> - /* >> - * Just execute from wherever we were loaded by the >> - * UEFI PE/COFF loader if the placement is suitable. >> - */ >> - *image_addr = (u64)_text; >> - *reserve_size = 0; >> - return EFI_SUCCESS; >> - } >> - >> - status = efi_allocate_pages_aligned(*reserve_size, >> reserve_addr, >> - ULONG_MAX, min_kimg_align, >> - EFI_LOADER_CODE); >> - >> - if (status != EFI_SUCCESS) { >> - efi_err("Failed to relocate kernel\n"); >> - *reserve_size = 0; >> - return status; >> - } >> - } >> - >> - *image_addr = *reserve_addr; >> - memcpy((void *)*image_addr, _text, kernel_size); >> - caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); >> + status = efi_kaslr_relocate_kernel(image_addr, >> + reserve_addr, reserve_size, >> + kernel_size, kernel_codesize, >> + kernel_memsize, >> + efi_kaslr_get_phys_seed(image_handle)); >> + if (status != EFI_SUCCESS) >> + return status; >> >> return EFI_SUCCESS; >> } >> diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c >> b/drivers/firmware/efi/libstub/efi-stub-helper.c >> index 1e0203d74691..40ac2625949c 100644 >> --- a/drivers/firmware/efi/libstub/efi-stub-helper.c >> +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c >> @@ -718,3 +718,154 @@ void efi_remap_image(unsigned long image_base, >> unsigned alloc_size, >> efi_warn("Failed to remap data region non-executable\n"); >> } >> } >> + >> +/** >> + * efi_kaslr_get_phys_seed() - Get random seed for physical kernel >> KASLR >> + * @image_handle: Handle to the image >> + * >> + * If KASLR is not disabled, obtain a random seed using >> EFI_RNG_PROTOCOL >> + * that will be used to move the kernel physical mapping. >> + * >> + * Return: the random seed >> + */ >> +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle) >> +{ >> + efi_status_t status; >> + u32 phys_seed; >> + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; >> + void *p; >> + >> + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) >> + return 0; >> + >> + if (efi_nokaslr) { >> + efi_info("KASLR disabled on kernel command line\n"); >> + } else if (efi_bs_call(handle_protocol, image_handle, >> + &li_fixed_proto, &p) == EFI_SUCCESS) { >> + efi_info("Image placement fixed by loader\n"); >> + } else { >> + status = efi_get_random_bytes(sizeof(phys_seed), >> + (u8 *)&phys_seed); >> + if (status == EFI_SUCCESS) { >> + return phys_seed; >> + } else if (status == EFI_NOT_FOUND) { >> + efi_info("EFI_RNG_PROTOCOL unavailable\n"); >> + efi_nokaslr = true; >> + } else if (status != EFI_SUCCESS) { >> + efi_err("efi_get_random_bytes() failed (0x%lx)\n", >> + status); >> + efi_nokaslr = true; >> + } >> + } >> + >> + return 0; >> +} >> + >> +/* >> + * Distro versions of GRUB may ignore the BSS allocation entirely >> (i.e., fail >> + * to provide space, and fail to zero it). Check for this condition >> by double >> + * checking that the first and the last byte of the image are >> covered by the >> + * same EFI memory map entry. >> + */ >> +static bool check_image_region(u64 base, u64 size) >> +{ >> + struct efi_boot_memmap *map; >> + efi_status_t status; >> + bool ret = false; >> + int map_offset; >> + >> + status = efi_get_memory_map(&map, false); >> + if (status != EFI_SUCCESS) >> + return false; >> + >> + for (map_offset = 0; map_offset < map->map_size; map_offset += >> map->desc_size) { >> + efi_memory_desc_t *md = (void *)map->map + map_offset; >> + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; >> + >> + /* >> + * Find the region that covers base, and return whether >> + * it covers base+size bytes. >> + */ >> + if (base >= md->phys_addr && base < end) { >> + ret = (base + size) <= end; >> + break; >> + } >> + } >> + >> + efi_bs_call(free_pool, map); >> + >> + return ret; >> +} >> + >> +/** >> + * efi_kaslr_relocate_kernel() - Relocate the kernel (random if >> KASLR enabled) >> + * @image_addr: Pointer to the current kernel location >> + * @reserve_addr: Pointer to the relocated kernel location >> + * @reserve_size: Size of the relocated kernel >> + * @kernel_size: Size of the text + data >> + * @kernel_codesize: Size of the text >> + * @kernel_memsize: Size of the text + data + bss >> + * @phys_seed: Random seed used for the relocation >> + * >> + * If KASLR is not enabled, this function relocates the kernel to a >> fixed >> + * address (or leave it as its current location). If KASLR is >> enabled, the >> + * kernel physical location is randomized using the seed in parameter. >> + * >> + * Return: status code, EFI_SUCCESS if relocation is successful >> + */ >> +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, >> + unsigned long *reserve_addr, >> + unsigned long *reserve_size, >> + unsigned long kernel_size, >> + unsigned long kernel_codesize, >> + unsigned long kernel_memsize, >> + u32 phys_seed) >> +{ >> + efi_status_t status; >> + u64 min_kimg_align = efi_get_kimg_min_align(); >> + >> + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { >> + /* >> + * If KASLR is enabled, and we have some randomness available, >> + * locate the kernel at a randomized offset in physical memory. >> + */ >> + status = efi_random_alloc(*reserve_size, min_kimg_align, >> + reserve_addr, phys_seed, >> + EFI_LOADER_CODE); >> + if (status != EFI_SUCCESS) >> + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); >> + } else { >> + status = EFI_OUT_OF_RESOURCES; >> + } >> + >> + if (status != EFI_SUCCESS) { >> + if (!check_image_region(*image_addr, kernel_memsize)) { >> + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI >> memory region\n"); >> + } else if (IS_ALIGNED(*image_addr, min_kimg_align) && >> + (u64)_end < EFI_ALLOC_LIMIT) { >> + /* >> + * Just execute from wherever we were loaded by the >> + * UEFI PE/COFF loader if the placement is suitable. >> + */ >> + *reserve_size = 0; >> + return EFI_SUCCESS; >> + } >> + >> + status = efi_allocate_pages_aligned(*reserve_size, >> reserve_addr, >> + ULONG_MAX, min_kimg_align, >> + EFI_LOADER_CODE); >> + >> + if (status != EFI_SUCCESS) { >> + efi_err("Failed to relocate kernel\n"); >> + *reserve_size = 0; >> + return status; >> + } >> + } >> + >> + memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); >> + *image_addr = *reserve_addr; >> + >> + caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); >> + >> + return status; >> +} >> diff --git a/drivers/firmware/efi/libstub/efistub.h >> b/drivers/firmware/efi/libstub/efistub.h >> index 6bd3bb86d967..64273371ce96 100644 >> --- a/drivers/firmware/efi/libstub/efistub.h >> +++ b/drivers/firmware/efi/libstub/efistub.h >> @@ -1098,5 +1098,13 @@ const u8 *__efi_get_smbios_string(u8 type, int >> offset, int recsize); >> >> void efi_remap_image(unsigned long image_base, unsigned alloc_size, >> unsigned long code_size); >> +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, >> + unsigned long *reserve_addr, >> + unsigned long *reserve_size, >> + unsigned long kernel_size, >> + unsigned long kernel_codesize, >> + unsigned long kernel_memsize, >> + u32 phys_seed); >> +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); >> >> #endif > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index d4a6b12a8741..b9e0d2cf09aa 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -14,42 +14,6 @@ #include "efistub.h" -/* - * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail - * to provide space, and fail to zero it). Check for this condition by double - * checking that the first and the last byte of the image are covered by the - * same EFI memory map entry. - */ -static bool check_image_region(u64 base, u64 size) -{ - struct efi_boot_memmap *map; - efi_status_t status; - bool ret = false; - int map_offset; - - status = efi_get_memory_map(&map, false); - if (status != EFI_SUCCESS) - return false; - - for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { - efi_memory_desc_t *md = (void *)map->map + map_offset; - u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; - - /* - * Find the region that covers base, and return whether - * it covers base+size bytes. - */ - if (base >= md->phys_addr && base < end) { - ret = (base + size) <= end; - break; - } - } - - efi_bs_call(free_pool, map); - - return ret; -} - efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, @@ -59,31 +23,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, { efi_status_t status; unsigned long kernel_size, kernel_codesize, kernel_memsize; - u32 phys_seed = 0; - u64 min_kimg_align = efi_get_kimg_min_align(); - - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { - efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; - void *p; - - if (efi_nokaslr) { - efi_info("KASLR disabled on kernel command line\n"); - } else if (efi_bs_call(handle_protocol, image_handle, - &li_fixed_proto, &p) == EFI_SUCCESS) { - efi_info("Image placement fixed by loader\n"); - } else { - status = efi_get_random_bytes(sizeof(phys_seed), - (u8 *)&phys_seed); - if (status == EFI_NOT_FOUND) { - efi_info("EFI_RNG_PROTOCOL unavailable\n"); - efi_nokaslr = true; - } else if (status != EFI_SUCCESS) { - efi_err("efi_get_random_bytes() failed (0x%lx)\n", - status); - efi_nokaslr = true; - } - } - } if (image->image_base != _text) efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n"); @@ -96,49 +35,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, kernel_codesize = __inittext_end - _text; kernel_memsize = kernel_size + (_end - _edata); *reserve_size = kernel_memsize; + *image_addr = (unsigned long)_text; - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { - /* - * If KASLR is enabled, and we have some randomness available, - * locate the kernel at a randomized offset in physical memory. - */ - status = efi_random_alloc(*reserve_size, min_kimg_align, - reserve_addr, phys_seed, - EFI_LOADER_CODE); - if (status != EFI_SUCCESS) - efi_warn("efi_random_alloc() failed: 0x%lx\n", status); - } else { - status = EFI_OUT_OF_RESOURCES; - } - - if (status != EFI_SUCCESS) { - if (!check_image_region((u64)_text, kernel_memsize)) { - efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); - } else if (IS_ALIGNED((u64)_text, min_kimg_align) && - (u64)_end < EFI_ALLOC_LIMIT) { - /* - * Just execute from wherever we were loaded by the - * UEFI PE/COFF loader if the placement is suitable. - */ - *image_addr = (u64)_text; - *reserve_size = 0; - return EFI_SUCCESS; - } - - status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, - ULONG_MAX, min_kimg_align, - EFI_LOADER_CODE); - - if (status != EFI_SUCCESS) { - efi_err("Failed to relocate kernel\n"); - *reserve_size = 0; - return status; - } - } - - *image_addr = *reserve_addr; - memcpy((void *)*image_addr, _text, kernel_size); - caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); + status = efi_kaslr_relocate_kernel(image_addr, + reserve_addr, reserve_size, + kernel_size, kernel_codesize, + kernel_memsize, + efi_kaslr_get_phys_seed(image_handle)); + if (status != EFI_SUCCESS) + return status; return EFI_SUCCESS; } diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 1e0203d74691..40ac2625949c 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -718,3 +718,154 @@ void efi_remap_image(unsigned long image_base, unsigned alloc_size, efi_warn("Failed to remap data region non-executable\n"); } } + +/** + * efi_kaslr_get_phys_seed() - Get random seed for physical kernel KASLR + * @image_handle: Handle to the image + * + * If KASLR is not disabled, obtain a random seed using EFI_RNG_PROTOCOL + * that will be used to move the kernel physical mapping. + * + * Return: the random seed + */ +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle) +{ + efi_status_t status; + u32 phys_seed; + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; + void *p; + + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + return 0; + + if (efi_nokaslr) { + efi_info("KASLR disabled on kernel command line\n"); + } else if (efi_bs_call(handle_protocol, image_handle, + &li_fixed_proto, &p) == EFI_SUCCESS) { + efi_info("Image placement fixed by loader\n"); + } else { + status = efi_get_random_bytes(sizeof(phys_seed), + (u8 *)&phys_seed); + if (status == EFI_SUCCESS) { + return phys_seed; + } else if (status == EFI_NOT_FOUND) { + efi_info("EFI_RNG_PROTOCOL unavailable\n"); + efi_nokaslr = true; + } else if (status != EFI_SUCCESS) { + efi_err("efi_get_random_bytes() failed (0x%lx)\n", + status); + efi_nokaslr = true; + } + } + + return 0; +} + +/* + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail + * to provide space, and fail to zero it). Check for this condition by double + * checking that the first and the last byte of the image are covered by the + * same EFI memory map entry. + */ +static bool check_image_region(u64 base, u64 size) +{ + struct efi_boot_memmap *map; + efi_status_t status; + bool ret = false; + int map_offset; + + status = efi_get_memory_map(&map, false); + if (status != EFI_SUCCESS) + return false; + + for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { + efi_memory_desc_t *md = (void *)map->map + map_offset; + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; + + /* + * Find the region that covers base, and return whether + * it covers base+size bytes. + */ + if (base >= md->phys_addr && base < end) { + ret = (base + size) <= end; + break; + } + } + + efi_bs_call(free_pool, map); + + return ret; +} + +/** + * efi_kaslr_relocate_kernel() - Relocate the kernel (random if KASLR enabled) + * @image_addr: Pointer to the current kernel location + * @reserve_addr: Pointer to the relocated kernel location + * @reserve_size: Size of the relocated kernel + * @kernel_size: Size of the text + data + * @kernel_codesize: Size of the text + * @kernel_memsize: Size of the text + data + bss + * @phys_seed: Random seed used for the relocation + * + * If KASLR is not enabled, this function relocates the kernel to a fixed + * address (or leave it as its current location). If KASLR is enabled, the + * kernel physical location is randomized using the seed in parameter. + * + * Return: status code, EFI_SUCCESS if relocation is successful + */ +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_codesize, + unsigned long kernel_memsize, + u32 phys_seed) +{ + efi_status_t status; + u64 min_kimg_align = efi_get_kimg_min_align(); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { + /* + * If KASLR is enabled, and we have some randomness available, + * locate the kernel at a randomized offset in physical memory. + */ + status = efi_random_alloc(*reserve_size, min_kimg_align, + reserve_addr, phys_seed, + EFI_LOADER_CODE); + if (status != EFI_SUCCESS) + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); + } else { + status = EFI_OUT_OF_RESOURCES; + } + + if (status != EFI_SUCCESS) { + if (!check_image_region(*image_addr, kernel_memsize)) { + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); + } else if (IS_ALIGNED(*image_addr, min_kimg_align) && + (u64)_end < EFI_ALLOC_LIMIT) { + /* + * Just execute from wherever we were loaded by the + * UEFI PE/COFF loader if the placement is suitable. + */ + *reserve_size = 0; + return EFI_SUCCESS; + } + + status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, + ULONG_MAX, min_kimg_align, + EFI_LOADER_CODE); + + if (status != EFI_SUCCESS) { + efi_err("Failed to relocate kernel\n"); + *reserve_size = 0; + return status; + } + } + + memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); + *image_addr = *reserve_addr; + + caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); + + return status; +} diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 6bd3bb86d967..64273371ce96 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -1098,5 +1098,13 @@ const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize); void efi_remap_image(unsigned long image_base, unsigned alloc_size, unsigned long code_size); +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_codesize, + unsigned long kernel_memsize, + u32 phys_seed); +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); #endif
This prepares for riscv to use the same functions to handle the pĥysical kernel move when KASLR is enabled. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- drivers/firmware/efi/libstub/arm64-stub.c | 111 +------------ .../firmware/efi/libstub/efi-stub-helper.c | 151 ++++++++++++++++++ drivers/firmware/efi/libstub/efistub.h | 8 + 3 files changed, 167 insertions(+), 103 deletions(-)