| Message ID | a1c01892bad6e4f05da96380b63ff14a82842d27.1662459668.git.baskov@ispras.ru (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | x86_64: Improvements at compressed kernel stage | expand |
On Tue, 6 Sept 2022 at 12:42, Evgeniy Baskov <baskov@ispras.ru> wrote: > > efi_adjust_memory_range_protection() can be useful outside x86-stub.c. > > Move it to mem.c, where memory related code resides and make it > non-static. > > Change its behavior to setup exact attibutes and disallow making memory > regions readable and writable simultaniosly for supported > configurations. > > Signed-off-by: Evgeniy Baskov <baskov@ispras.ru> Acked-by: Ard Biesheuvel <ardb@kernel.org> > --- > drivers/firmware/efi/libstub/efistub.h | 4 + > drivers/firmware/efi/libstub/mem.c | 101 ++++++++++++++++++++++++ > drivers/firmware/efi/libstub/x86-stub.c | 67 ++-------------- > 3 files changed, 111 insertions(+), 61 deletions(-) > > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h > index b0ae0a454404..22fe28385db7 100644 > --- a/drivers/firmware/efi/libstub/efistub.h > +++ b/drivers/firmware/efi/libstub/efistub.h > @@ -907,6 +907,10 @@ efi_status_t efi_relocate_kernel(unsigned long *image_addr, > unsigned long alignment, > unsigned long min_addr); > > +efi_status_t efi_adjust_memory_range_protection(unsigned long start, > + unsigned long size, > + unsigned long attributes); > + > efi_status_t efi_parse_options(char const *cmdline); > > void efi_parse_option_graphics(char *option); > diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c > index feef8d4be113..89ebc8ad2c22 100644 > --- a/drivers/firmware/efi/libstub/mem.c > +++ b/drivers/firmware/efi/libstub/mem.c > @@ -130,3 +130,104 @@ void efi_free(unsigned long size, unsigned long addr) > nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE; > efi_bs_call(free_pages, addr, nr_pages); > } > + > +/** > + * efi_adjust_memory_range_protection() - change memory range protection attributes > + * @start: memory range start address > + * @size: memory range size > + * > + * Actual memory range for which memory attributes are modified is > + * the smallest ranged with start address and size aligned to EFI_PAGE_SIZE > + * that includes [start, start + size]. > + * > + * @return: status code > + */ > +efi_status_t efi_adjust_memory_range_protection(unsigned long start, > + unsigned long size, > + unsigned long attributes) > +{ > + efi_status_t status; > + efi_gcd_memory_space_desc_t desc; > + efi_physical_addr_t end, next; > + efi_physical_addr_t rounded_start, rounded_end; > + efi_physical_addr_t unprotect_start, unprotect_size; > + int has_system_memory = 0; > + > + if (efi_dxe_table == NULL) > + return EFI_UNSUPPORTED; > + > + /* > + * This function should not be used to modify attributes > + * other than writable/executable. > + */ > + > + if ((attributes & ~(EFI_MEMORY_RO | EFI_MEMORY_XP)) != 0) > + return EFI_INVALID_PARAMETER; > + > + /* > + * Disallow simultaniously executable and writable memory > + * to inforce W^X policy if direct extraction code is enabled. > + */ > + > + if ((attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0 && > + IS_ENABLED(CONFIG_EFI_STUB_EXTRACT_DIRECT)) > + return EFI_INVALID_PARAMETER; > + > + rounded_start = rounddown(start, EFI_PAGE_SIZE); > + rounded_end = roundup(start + size, EFI_PAGE_SIZE); > + > + /* > + * Don't modify memory region attributes, they are > + * already suitable, to lower the possibility to > + * encounter firmware bugs. > + */ > + > + for (end = start + size; start < end; start = next) { > + > + status = efi_dxe_call(get_memory_space_descriptor, > + start, &desc); > + > + if (status != EFI_SUCCESS) { > + efi_warn("Unable to get memory descriptor at %lx\n", > + start); > + return status; > + } > + > + next = desc.base_address + desc.length; > + > + /* > + * Only system memory is suitable for trampoline/kernel image > + * placement, so only this type of memory needs its attributes > + * to be modified. > + */ > + > + if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory) { > + efi_warn("Attempted to change protection of special memory range\n"); > + return EFI_UNSUPPORTED; > + } > + > + if (((desc.attributes ^ attributes) & > + (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) > + continue; > + > + desc.attributes &= ~(EFI_MEMORY_RO | EFI_MEMORY_XP); > + desc.attributes |= attributes; > + > + unprotect_start = max(rounded_start, desc.base_address); > + unprotect_size = min(rounded_end, next) - unprotect_start; > + > + status = efi_dxe_call(set_memory_space_attributes, > + unprotect_start, unprotect_size, > + desc.attributes); > + > + if (status != EFI_SUCCESS) { > + efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n", > + (unsigned long)unprotect_start, > + (unsigned long)(unprotect_start + unprotect_size), > + status); > + return status; > + } > + } > + > + return EFI_SUCCESS; > +} > diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c > index 05ae8bcc9d67..678f9c2ccafc 100644 > --- a/drivers/firmware/efi/libstub/x86-stub.c > +++ b/drivers/firmware/efi/libstub/x86-stub.c > @@ -212,62 +212,6 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params) > } > } > > -static void > -adjust_memory_range_protection(unsigned long start, unsigned long size) > -{ > - efi_status_t status; > - efi_gcd_memory_space_desc_t desc; > - unsigned long end, next; > - unsigned long rounded_start, rounded_end; > - unsigned long unprotect_start, unprotect_size; > - int has_system_memory = 0; > - > - if (efi_dxe_table == NULL) > - return; > - > - rounded_start = rounddown(start, EFI_PAGE_SIZE); > - rounded_end = roundup(start + size, EFI_PAGE_SIZE); > - > - /* > - * Don't modify memory region attributes, they are > - * already suitable, to lower the possibility to > - * encounter firmware bugs. > - */ > - > - for (end = start + size; start < end; start = next) { > - > - status = efi_dxe_call(get_memory_space_descriptor, start, &desc); > - > - if (status != EFI_SUCCESS) > - return; > - > - next = desc.base_address + desc.length; > - > - /* > - * Only system memory is suitable for trampoline/kernel image placement, > - * so only this type of memory needs its attributes to be modified. > - */ > - > - if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory || > - (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) > - continue; > - > - unprotect_start = max(rounded_start, (unsigned long)desc.base_address); > - unprotect_size = min(rounded_end, next) - unprotect_start; > - > - status = efi_dxe_call(set_memory_space_attributes, > - unprotect_start, unprotect_size, > - EFI_MEMORY_WB); > - > - if (status != EFI_SUCCESS) { > - efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n", > - unprotect_start, > - unprotect_start + unprotect_size, > - status); > - } > - } > -} > - > /* > * Trampoline takes 2 pages and can be loaded in first megabyte of memory > * with its end placed between 128k and 640k where BIOS might start. > @@ -291,12 +235,12 @@ setup_memory_protection(unsigned long image_base, unsigned long image_size) > * and relocated kernel image. > */ > > - adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE, > - TRAMPOLINE_PLACEMENT_SIZE); > + efi_adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE, > + TRAMPOLINE_PLACEMENT_SIZE, 0); > > #ifdef CONFIG_64BIT > if (image_base != (unsigned long)startup_32) > - adjust_memory_range_protection(image_base, image_size); > + efi_adjust_memory_range_protection(image_base, image_size, 0); > #else > /* > * Clear protection flags on a whole range of possible > @@ -306,8 +250,9 @@ setup_memory_protection(unsigned long image_base, unsigned long image_size) > * need to remove possible protection on relocated image > * itself disregarding further relocations. > */ > - adjust_memory_range_protection(LOAD_PHYSICAL_ADDR, > - KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR); > + efi_adjust_memory_range_protection(LOAD_PHYSICAL_ADDR, > + KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR, > + 0); > #endif > } > > -- > 2.35.1 >
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index b0ae0a454404..22fe28385db7 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -907,6 +907,10 @@ efi_status_t efi_relocate_kernel(unsigned long *image_addr, unsigned long alignment, unsigned long min_addr); +efi_status_t efi_adjust_memory_range_protection(unsigned long start, + unsigned long size, + unsigned long attributes); + efi_status_t efi_parse_options(char const *cmdline); void efi_parse_option_graphics(char *option); diff --git a/drivers/firmware/efi/libstub/mem.c b/drivers/firmware/efi/libstub/mem.c index feef8d4be113..89ebc8ad2c22 100644 --- a/drivers/firmware/efi/libstub/mem.c +++ b/drivers/firmware/efi/libstub/mem.c @@ -130,3 +130,104 @@ void efi_free(unsigned long size, unsigned long addr) nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE; efi_bs_call(free_pages, addr, nr_pages); } + +/** + * efi_adjust_memory_range_protection() - change memory range protection attributes + * @start: memory range start address + * @size: memory range size + * + * Actual memory range for which memory attributes are modified is + * the smallest ranged with start address and size aligned to EFI_PAGE_SIZE + * that includes [start, start + size]. + * + * @return: status code + */ +efi_status_t efi_adjust_memory_range_protection(unsigned long start, + unsigned long size, + unsigned long attributes) +{ + efi_status_t status; + efi_gcd_memory_space_desc_t desc; + efi_physical_addr_t end, next; + efi_physical_addr_t rounded_start, rounded_end; + efi_physical_addr_t unprotect_start, unprotect_size; + int has_system_memory = 0; + + if (efi_dxe_table == NULL) + return EFI_UNSUPPORTED; + + /* + * This function should not be used to modify attributes + * other than writable/executable. + */ + + if ((attributes & ~(EFI_MEMORY_RO | EFI_MEMORY_XP)) != 0) + return EFI_INVALID_PARAMETER; + + /* + * Disallow simultaniously executable and writable memory + * to inforce W^X policy if direct extraction code is enabled. + */ + + if ((attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0 && + IS_ENABLED(CONFIG_EFI_STUB_EXTRACT_DIRECT)) + return EFI_INVALID_PARAMETER; + + rounded_start = rounddown(start, EFI_PAGE_SIZE); + rounded_end = roundup(start + size, EFI_PAGE_SIZE); + + /* + * Don't modify memory region attributes, they are + * already suitable, to lower the possibility to + * encounter firmware bugs. + */ + + for (end = start + size; start < end; start = next) { + + status = efi_dxe_call(get_memory_space_descriptor, + start, &desc); + + if (status != EFI_SUCCESS) { + efi_warn("Unable to get memory descriptor at %lx\n", + start); + return status; + } + + next = desc.base_address + desc.length; + + /* + * Only system memory is suitable for trampoline/kernel image + * placement, so only this type of memory needs its attributes + * to be modified. + */ + + if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory) { + efi_warn("Attempted to change protection of special memory range\n"); + return EFI_UNSUPPORTED; + } + + if (((desc.attributes ^ attributes) & + (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) + continue; + + desc.attributes &= ~(EFI_MEMORY_RO | EFI_MEMORY_XP); + desc.attributes |= attributes; + + unprotect_start = max(rounded_start, desc.base_address); + unprotect_size = min(rounded_end, next) - unprotect_start; + + status = efi_dxe_call(set_memory_space_attributes, + unprotect_start, unprotect_size, + desc.attributes); + + if (status != EFI_SUCCESS) { + efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n", + (unsigned long)unprotect_start, + (unsigned long)(unprotect_start + unprotect_size), + status); + return status; + } + } + + return EFI_SUCCESS; +} diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 05ae8bcc9d67..678f9c2ccafc 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -212,62 +212,6 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params) } } -static void -adjust_memory_range_protection(unsigned long start, unsigned long size) -{ - efi_status_t status; - efi_gcd_memory_space_desc_t desc; - unsigned long end, next; - unsigned long rounded_start, rounded_end; - unsigned long unprotect_start, unprotect_size; - int has_system_memory = 0; - - if (efi_dxe_table == NULL) - return; - - rounded_start = rounddown(start, EFI_PAGE_SIZE); - rounded_end = roundup(start + size, EFI_PAGE_SIZE); - - /* - * Don't modify memory region attributes, they are - * already suitable, to lower the possibility to - * encounter firmware bugs. - */ - - for (end = start + size; start < end; start = next) { - - status = efi_dxe_call(get_memory_space_descriptor, start, &desc); - - if (status != EFI_SUCCESS) - return; - - next = desc.base_address + desc.length; - - /* - * Only system memory is suitable for trampoline/kernel image placement, - * so only this type of memory needs its attributes to be modified. - */ - - if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory || - (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) - continue; - - unprotect_start = max(rounded_start, (unsigned long)desc.base_address); - unprotect_size = min(rounded_end, next) - unprotect_start; - - status = efi_dxe_call(set_memory_space_attributes, - unprotect_start, unprotect_size, - EFI_MEMORY_WB); - - if (status != EFI_SUCCESS) { - efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n", - unprotect_start, - unprotect_start + unprotect_size, - status); - } - } -} - /* * Trampoline takes 2 pages and can be loaded in first megabyte of memory * with its end placed between 128k and 640k where BIOS might start. @@ -291,12 +235,12 @@ setup_memory_protection(unsigned long image_base, unsigned long image_size) * and relocated kernel image. */ - adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE, - TRAMPOLINE_PLACEMENT_SIZE); + efi_adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE, + TRAMPOLINE_PLACEMENT_SIZE, 0); #ifdef CONFIG_64BIT if (image_base != (unsigned long)startup_32) - adjust_memory_range_protection(image_base, image_size); + efi_adjust_memory_range_protection(image_base, image_size, 0); #else /* * Clear protection flags on a whole range of possible @@ -306,8 +250,9 @@ setup_memory_protection(unsigned long image_base, unsigned long image_size) * need to remove possible protection on relocated image * itself disregarding further relocations. */ - adjust_memory_range_protection(LOAD_PHYSICAL_ADDR, - KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR); + efi_adjust_memory_range_protection(LOAD_PHYSICAL_ADDR, + KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR, + 0); #endif }
efi_adjust_memory_range_protection() can be useful outside x86-stub.c. Move it to mem.c, where memory related code resides and make it non-static. Change its behavior to setup exact attibutes and disallow making memory regions readable and writable simultaniosly for supported configurations. Signed-off-by: Evgeniy Baskov <baskov@ispras.ru> --- drivers/firmware/efi/libstub/efistub.h | 4 + drivers/firmware/efi/libstub/mem.c | 101 ++++++++++++++++++++++++ drivers/firmware/efi/libstub/x86-stub.c | 67 ++-------------- 3 files changed, 111 insertions(+), 61 deletions(-)