From: Jann Horn jannh@google.com
stable inclusion from stable-v5.10.104 commit 667df6fe3ece20aaaefc8838659a7e0504cd9a32 bugzilla: https://gitee.com/openeuler/kernel/issues/I56XAC
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/firmware/efi/vars.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index abdc8a6a3963..cae590bd08f2 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -742,6 +742,7 @@ int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, { 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 *name, efi_guid_t vendor, u32 attributes, 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;