From fcf63d6b8ab9b12c2ce1b4bde12a3c391029c998 Mon Sep 17 00:00:00 2001 From: Andrew Donnellan Date: Fri, 10 Feb 2023 19:03:37 +1100 Subject: [PATCH] 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: Benjamin Gray Fixes: 2454a7af0f2a ("powerpc/pseries: define driver for Platform KeyStore") Signed-off-by: Andrew Donnellan Reviewed-by: Russell Currey Signed-off-by: Russell Currey Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230210080401.345462-3-ajd@linux.ibm.com --- arch/powerpc/platforms/pseries/plpks.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c index 9e85b6d..a01cf2f 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -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); -- 2.7.4