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Subject[PATCH] efivars: Respect "block" flag in efivar_entry_set_safe()
Date
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. So I'm not marking this for stable backporting.

Fixes: ca0e30dcaa53 ("efi: Add nonblocking option to efi_query_variable_store()")
Signed-off-by: Jann Horn <jannh@google.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;
base-commit: 83e396641110663d3c7bb25b9bc0c6a750359ecf
--
2.35.1.473.g83b2b277ed-goog

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