Commit fcf63d6b authored by Andrew Donnellan's avatar Andrew Donnellan Committed by Michael Ellerman
Browse files

powerpc/pseries: Fix alignment of PLPKS structures and buffers 



A number of structures and buffers passed to PKS hcalls have alignment
requirements, which could on occasion cause problems:

- Authorisation structures must be 16-byte aligned and must not cross a
  page boundary

- Label structures must not cross page boundaries

- Password output buffers must not cross page boundaries

To ensure correct alignment, we adjust the allocation size of each of
these structures/buffers to be the closest power of 2 that is at least the
size of the structure/buffer (since kmalloc() guarantees that an
allocation of a power of 2 size will be aligned to at least that size).

Reported-by: default avatarBenjamin Gray <bgray@linux.ibm.com>
Fixes: 2454a7af ("powerpc/pseries: define driver for Platform KeyStore")
Signed-off-by: default avatarAndrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: default avatarRussell Currey <ruscur@russell.cc>
Signed-off-by: default avatarRussell Currey <ruscur@russell.cc>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230210080401.345462-3-ajd@linux.ibm.com
parent f74dcbfd

arch/powerpc/platforms/pseries/plpks.c

+7 −3
Original line number Diff line number Diff line
@@ -126,7 +126,8 @@ static int plpks_gen_password(void) 
	u8 *password, consumer = PKS_OS_OWNER;

	int rc;



	password = kzalloc(maxpwsize, GFP_KERNEL);

	// The password must not cross a page boundary, so we align to the next power of 2

	password = kzalloc(roundup_pow_of_two(maxpwsize), GFP_KERNEL);

	if (!password)

		return -ENOMEM;
@@ -162,7 +163,9 @@ static struct plpks_auth *construct_auth(u8 consumer) 
	if (consumer > PKS_OS_OWNER)

		return ERR_PTR(-EINVAL);



	auth = kzalloc(struct_size(auth, password, maxpwsize), GFP_KERNEL);

	// The auth structure must not cross a page boundary and must be

	// 16 byte aligned. We align to the next largest power of 2

	auth = kzalloc(roundup_pow_of_two(struct_size(auth, password, maxpwsize)), GFP_KERNEL);

	if (!auth)

		return ERR_PTR(-ENOMEM);
@@ -196,7 +199,8 @@ static struct label *construct_label(char *component, u8 varos, u8 *name, 
	if (component && slen > sizeof(label->attr.prefix))

		return ERR_PTR(-EINVAL);



	label = kzalloc(sizeof(*label), GFP_KERNEL);

	// The label structure must not cross a page boundary, so we align to the next power of 2

	label = kzalloc(roundup_pow_of_two(sizeof(*label)), GFP_KERNEL);

	if (!label)

		return ERR_PTR(-ENOMEM);