4.19-stable patches

added patches:
	efivarfs-request-at-most-512-bytes-for-variable-names.patch

diff --git a/queue-4.19/efivarfs-request-at-most-512-bytes-for-variable-names.patch b/queue-4.19/efivarfs-request-at-most-512-bytes-for-variable-names.patch
new file mode 100644 (file)
index 0000000..e994b1a
--- /dev/null
+++ b/queue-4.19/efivarfs-request-at-most-512-bytes-for-variable-names.patch
@@ -0,0 +1,76 @@
+From f45812cc23fb74bef62d4eb8a69fe7218f4b9f2a Mon Sep 17 00:00:00 2001
+From: Tim Schumacher <timschumi@gmx.de>
+Date: Fri, 26 Jan 2024 17:25:23 +0100
+Subject: efivarfs: Request at most 512 bytes for variable names
+
+From: Tim Schumacher <timschumi@gmx.de>
+
+commit f45812cc23fb74bef62d4eb8a69fe7218f4b9f2a upstream.
+
+Work around a quirk in a few old (2011-ish) UEFI implementations, where
+a call to `GetNextVariableName` with a buffer size larger than 512 bytes
+will always return EFI_INVALID_PARAMETER.
+
+There is some lore around EFI variable names being up to 1024 bytes in
+size, but this has no basis in the UEFI specification, and the upper
+bounds are typically platform specific, and apply to the entire variable
+(name plus payload).
+
+Given that Linux does not permit creating files with names longer than
+NAME_MAX (255) bytes, 512 bytes (== 256 UTF-16 characters) is a
+reasonable limit.
+
+Cc: <stable@vger.kernel.org> # 6.1+
+Signed-off-by: Tim Schumacher <timschumi@gmx.de>
+Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
+[timschumi@gmx.de: adjusted diff for changed context and code move]
+Signed-off-by: Tim Schumacher <timschumi@gmx.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/firmware/efi/vars.c |   17 +++++++++++------
+ 1 file changed, 11 insertions(+), 6 deletions(-)
+
+--- a/drivers/firmware/efi/vars.c
++++ b/drivers/firmware/efi/vars.c
+@@ -440,7 +440,7 @@ int efivar_init(int (*func)(efi_char16_t
+               void *data, bool duplicates, struct list_head *head)
+ {
+       const struct efivar_operations *ops;
+-      unsigned long variable_name_size = 1024;
++      unsigned long variable_name_size = 512;
+       efi_char16_t *variable_name;
+       efi_status_t status;
+       efi_guid_t vendor_guid;
+@@ -463,12 +463,13 @@ int efivar_init(int (*func)(efi_char16_t
+       }
+ 
+       /*
+-       * Per EFI spec, the maximum storage allocated for both
+-       * the variable name and variable data is 1024 bytes.
++       * A small set of old UEFI implementations reject sizes
++       * above a certain threshold, the lowest seen in the wild
++       * is 512.
+        */
+ 
+       do {
+-              variable_name_size = 1024;
++              variable_name_size = 512;
+ 
+               status = ops->get_next_variable(&variable_name_size,
+                                               variable_name,
+@@ -512,9 +513,13 @@ int efivar_init(int (*func)(efi_char16_t
+                       break;
+               case EFI_NOT_FOUND:
+                       break;
++              case EFI_BUFFER_TOO_SMALL:
++                      pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n",
++                              variable_name_size);
++                      status = EFI_NOT_FOUND;
++                      break;
+               default:
+-                      printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
+-                              status);
++                      pr_warn("efivars: get_next_variable: status=%lx\n", status);
+                       status = EFI_NOT_FOUND;
+                       break;
+               }

diff --git a/queue-4.19/series b/queue-4.19/series
index 001c8f60dc1778987dd13b1cf5ff5ef6ae2a352b..d38eed6da161ca26bd653b42833bc52bf99928e5 100644 (file)
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -86,6 +86,7 @@ loop-factor-out-setting-loop-device-size.patch
 loop-refactor-loop_set_status-size-calculation.patch
 loop-properly-observe-rotational-flag-of-underlying-device.patch
 perf-core-fix-reentry-problem-in-perf_output_read_group.patch
+efivarfs-request-at-most-512-bytes-for-variable-names.patch
 loop-factor-out-configuring-loop-from-status.patch
 loop-check-for-overflow-while-configuring-loop.patch
 loop-loop_set_status_from_info-check-before-assignment.patch