From 8a254d90a77580244ec57e82bca7eb65656cc167 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 19 Oct 2022 23:29:58 +0200 Subject: efi: efivars: Fix variable writes without query_variable_store() Commit bbc6d2c6ef22 ("efi: vars: Switch to new wrapper layer") refactored the efivars layer so that the 'business logic' related to which UEFI variables affect the boot flow in which way could be moved out of it, and into the efivarfs driver. This inadvertently broke setting variables on firmware implementations that lack the QueryVariableInfo() boot service, because we no longer tolerate a EFI_UNSUPPORTED result from check_var_size() when calling efivar_entry_set_get_size(), which now ends up calling check_var_size() a second time inadvertently. If QueryVariableInfo() is missing, we support writes of up to 64k - let's move that logic into check_var_size(), and drop the redundant call. Cc: # v6.0 Fixes: bbc6d2c6ef22 ("efi: vars: Switch to new wrapper layer") Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/vars.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/firmware/efi/vars.c') diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index dd74d2ad3184..433b61587139 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -20,19 +21,19 @@ static struct efivars *__efivars; static DEFINE_SEMAPHORE(efivars_lock); -efi_status_t check_var_size(u32 attributes, unsigned long size) +static efi_status_t check_var_size(u32 attributes, unsigned long size) { const struct efivar_operations *fops; fops = __efivars->ops; if (!fops->query_variable_store) - return EFI_UNSUPPORTED; + return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES; return fops->query_variable_store(attributes, size, false); } -EXPORT_SYMBOL_NS_GPL(check_var_size, EFIVAR); +static efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size) { const struct efivar_operations *fops; @@ -40,11 +41,10 @@ efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size) fops = __efivars->ops; if (!fops->query_variable_store) - return EFI_UNSUPPORTED; + return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES; return fops->query_variable_store(attributes, size, true); } -EXPORT_SYMBOL_NS_GPL(check_var_size_nonblocking, EFIVAR); /** * efivars_kobject - get the kobject for the registered efivars -- cgit v1.2.3 From f11a74b45d330ad1ab986852b099747161052526 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 27 Oct 2022 15:52:31 +0200 Subject: efi: efivars: Fix variable writes with unsupported query_variable_store() Commit 8a254d90a775 ("efi: efivars: Fix variable writes without query_variable_store()") addressed an issue that was introduced during the EFI variable store refactor, where alternative implementations of the efivars layer that lacked query_variable_store() would no longer work. Unfortunately, there is another case to consider here, which was missed: if the efivars layer is backed by the EFI runtime services as usual, but the EFI implementation predates the introduction of QueryVariableInfo(), we will return EFI_UNSUPPORTED, and this is no longer being dealt with correctly. So let's fix this, and while at it, clean up the code a bit, by merging the check_var_size() routines as well as their callers. Cc: # v6.0 Fixes: bbc6d2c6ef22 ("efi: vars: Switch to new wrapper layer") Signed-off-by: Ard Biesheuvel Tested-by: Aditya Garg --- drivers/firmware/efi/vars.c | 68 +++++++++++++-------------------------------- 1 file changed, 20 insertions(+), 48 deletions(-) (limited to 'drivers/firmware/efi/vars.c') diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 433b61587139..0ba9f18312f5 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -21,29 +21,22 @@ static struct efivars *__efivars; static DEFINE_SEMAPHORE(efivars_lock); -static efi_status_t check_var_size(u32 attributes, unsigned long size) -{ - const struct efivar_operations *fops; - - fops = __efivars->ops; - - if (!fops->query_variable_store) - return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES; - - return fops->query_variable_store(attributes, size, false); -} - -static -efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size) +static efi_status_t check_var_size(bool nonblocking, u32 attributes, + unsigned long size) { const struct efivar_operations *fops; + efi_status_t status; fops = __efivars->ops; if (!fops->query_variable_store) + status = EFI_UNSUPPORTED; + else + status = fops->query_variable_store(attributes, size, + nonblocking); + if (status == EFI_UNSUPPORTED) return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES; - - return fops->query_variable_store(attributes, size, true); + return status; } /** @@ -195,26 +188,6 @@ efi_status_t efivar_get_next_variable(unsigned long *name_size, } EXPORT_SYMBOL_NS_GPL(efivar_get_next_variable, EFIVAR); -/* - * efivar_set_variable_blocking() - local helper function for set_variable - * - * Must be called with efivars_lock held. - */ -static efi_status_t -efivar_set_variable_blocking(efi_char16_t *name, efi_guid_t *vendor, - u32 attr, unsigned long data_size, void *data) -{ - efi_status_t status; - - if (data_size > 0) { - status = check_var_size(attr, data_size + - ucs2_strsize(name, 1024)); - if (status != EFI_SUCCESS) - return status; - } - return __efivars->ops->set_variable(name, vendor, attr, data_size, data); -} - /* * efivar_set_variable_locked() - set a variable identified by name/vendor * @@ -228,23 +201,21 @@ efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, efi_set_variable_t *setvar; efi_status_t status; - if (!nonblocking) - return efivar_set_variable_blocking(name, vendor, attr, - data_size, data); + if (data_size > 0) { + status = check_var_size(nonblocking, attr, + data_size + ucs2_strsize(name, 1024)); + if (status != EFI_SUCCESS) + return status; + } /* * If no _nonblocking variant exists, the ordinary one * is assumed to be non-blocking. */ - setvar = __efivars->ops->set_variable_nonblocking ?: - __efivars->ops->set_variable; + setvar = __efivars->ops->set_variable_nonblocking; + if (!setvar || !nonblocking) + setvar = __efivars->ops->set_variable; - if (data_size > 0) { - status = check_var_size_nonblocking(attr, data_size + - ucs2_strsize(name, 1024)); - if (status != EFI_SUCCESS) - return status; - } return setvar(name, vendor, attr, data_size, data); } EXPORT_SYMBOL_NS_GPL(efivar_set_variable_locked, EFIVAR); @@ -264,7 +235,8 @@ efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, if (efivar_lock()) return EFI_ABORTED; - status = efivar_set_variable_blocking(name, vendor, attr, data_size, data); + status = efivar_set_variable_locked(name, vendor, attr, data_size, + data, false); efivar_unlock(); return status; } -- cgit v1.2.3