From: Jann Horn jannh@google.com
commit 258dd902022cb10c83671176688074879517fd21 upstream.
When the "block" flag is false, the old code would sometimes still call check_var_size(), which wrongly tells ->query_variable_store() that it can block.
As far as I can tell, this can't really materialize as a bug at the moment, because ->query_variable_store only does something on X86 with generic EFI, and in that configuration we always take the efivar_entry_set_nonblocking() path.
Fixes: ca0e30dcaa53 ("efi: Add nonblocking option to efi_query_variable_store()") Signed-off-by: Jann Horn jannh@google.com Signed-off-by: Ard Biesheuvel ardb@kernel.org Link: https://lore.kernel.org/r/20220218180559.1432559-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/efi/vars.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -742,6 +742,7 @@ int efivar_entry_set_safe(efi_char16_t * { const struct efivar_operations *ops; efi_status_t status; + unsigned long varsize;
if (!__efivars) return -EINVAL; @@ -764,15 +765,17 @@ int efivar_entry_set_safe(efi_char16_t * return efivar_entry_set_nonblocking(name, vendor, attributes, size, data);
+ varsize = size + ucs2_strsize(name, 1024); if (!block) { if (down_trylock(&efivars_lock)) return -EBUSY; + status = check_var_size_nonblocking(attributes, varsize); } else { if (down_interruptible(&efivars_lock)) return -EINTR; + status = check_var_size(attributes, varsize); }
- status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); if (status != EFI_SUCCESS) { up(&efivars_lock); return -ENOSPC;