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[v2,1/4] efi: pstore: Request at most 512 bytes for variable names

Message ID 20240328205041.76812-1-timschumi@gmx.de
State Accepted
Commit 24427cda90cbbb9015c73e2dd3329a116a00c8de
Headers show
Series [v2,1/4] efi: pstore: Request at most 512 bytes for variable names | expand

Commit Message

Tim Schumacher March 28, 2024, 8:50 p.m. UTC
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.

This was already done to efivarfs in commit f45812cc23fb ("efivarfs:
Request at most 512 bytes for variable names"), but the second copy of
the variable iteration implementation was overlooked.

Signed-off-by: Tim Schumacher <timschumi@gmx.de>
---
Changes from v1:
 - None, resubmitted as a part of a chain.
---
 drivers/firmware/efi/efi-pstore.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--
2.44.0
diff mbox series

Patch

diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 833cbb995dd3f..5b9dc26e6bcb9 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -162,7 +162,15 @@  static ssize_t efi_pstore_read(struct pstore_record *record)
 	efi_status_t status;

 	for (;;) {
-		varname_size = 1024;
+		/*
+		 * A small set of old UEFI implementations reject sizes
+		 * above a certain threshold, the lowest seen in the wild
+		 * is 512.
+		 *
+		 * TODO: Commonize with the iteration implementation in
+		 *       fs/efivarfs to keep all the quirks in one place.
+		 */
+		varname_size = 512;

 		/*
 		 * If this is the first read() call in the pstore enumeration,