From 24427cda90cbbb9015c73e2dd3329a116a00c8de Mon Sep 17 00:00:00 2001 From: Tim Schumacher Date: Thu, 28 Mar 2024 21:50:30 +0100 Subject: [PATCH] efi: pstore: Request at most 512 bytes for variable names 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 Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/efi-pstore.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c index 833cbb995dd3..5b9dc26e6bcb 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,