diff options
Diffstat (limited to 'debian/patches/bugfix/x86/x86-efistub-Clear-decompressor-BSS-in-native-EFI-ent.patch')
| -rw-r--r-- | debian/patches/bugfix/x86/x86-efistub-Clear-decompressor-BSS-in-native-EFI-ent.patch | 68 |
1 files changed, 0 insertions, 68 deletions
diff --git a/debian/patches/bugfix/x86/x86-efistub-Clear-decompressor-BSS-in-native-EFI-ent.patch b/debian/patches/bugfix/x86/x86-efistub-Clear-decompressor-BSS-in-native-EFI-ent.patch deleted file mode 100644 index 63c4cafae..000000000 --- a/debian/patches/bugfix/x86/x86-efistub-Clear-decompressor-BSS-in-native-EFI-ent.patch +++ /dev/null @@ -1,68 +0,0 @@ -From: Ard Biesheuvel <ardb@kernel.org> -Date: Fri, 15 Mar 2024 16:26:16 +0100 -Subject: x86/efistub: Clear decompressor BSS in native EFI entrypoint -Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=9274ec2003042bf0ed847cb80ffcfab543a0a33a - -[ Upstream commit b3810c5a2cc4a6665f7a65bed5393c75ce3f3aa2 ] - -The EFI stub on x86 no longer invokes the decompressor as a subsequent -boot stage, but calls into the decompression code directly while running -in the context of the EFI boot services. - -This means that when using the native EFI entrypoint (as opposed to the -EFI handover protocol, which clears BSS explicitly), the firmware PE -image loader is being relied upon to ensure that BSS is zeroed before -the EFI stub is entered from the firmware. - -As Radek's report proves, this is a bad idea. Not all loaders do this -correctly, which means some global variables that should be statically -initialized to 0x0 may have junk in them. - -So clear BSS explicitly when entering via efi_pe_entry(). Note that -zeroing BSS from C code is not generally safe, but in this case, the -following assignment and dereference of a global pointer variable -ensures that the memset() cannot be deferred or reordered. - -Cc: <stable@kernel.org> # v6.1+ -Reported-by: Radek Podgorny <radek@podgorny.cz> -Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz -Signed-off-by: Ard Biesheuvel <ardb@kernel.org> -Signed-off-by: Sasha Levin <sashal@kernel.org> ---- - drivers/firmware/efi/libstub/x86-stub.c | 6 ++++-- - 1 file changed, 4 insertions(+), 2 deletions(-) - -diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c -index 784e1b2ae5cc..aa07051459f5 100644 ---- a/drivers/firmware/efi/libstub/x86-stub.c -+++ b/drivers/firmware/efi/libstub/x86-stub.c -@@ -21,6 +21,8 @@ - #include "efistub.h" - #include "x86-stub.h" - -+extern char _bss[], _ebss[]; -+ - const efi_system_table_t *efi_system_table; - const efi_dxe_services_table_t *efi_dxe_table; - static efi_loaded_image_t *image = NULL; -@@ -432,6 +434,8 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, - efi_status_t status; - char *cmdline_ptr; - -+ memset(_bss, 0, _ebss - _bss); -+ - efi_system_table = sys_table_arg; - - /* Check if we were booted by the EFI firmware */ -@@ -950,8 +954,6 @@ void __noreturn efi_stub_entry(efi_handle_t handle, - void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, - struct boot_params *boot_params) - { -- extern char _bss[], _ebss[]; -- - memset(_bss, 0, _ebss - _bss); - efi_stub_entry(handle, sys_table_arg, boot_params); - } --- -2.43.0 - |