6.1-stable review patch. If anyone has any objections, please let me know.
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From: Andrew Donnellan ajd@linux.ibm.com
[ Upstream commit fcf63d6b8ab9b12c2ce1b4bde12a3c391029c998 ]
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 bgray@linux.ibm.com Fixes: 2454a7af0f2a ("powerpc/pseries: define driver for Platform KeyStore") Signed-off-by: Andrew Donnellan ajd@linux.ibm.com Reviewed-by: Russell Currey ruscur@russell.cc Signed-off-by: Russell Currey ruscur@russell.cc Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20230210080401.345462-3-ajd@linux.ibm.com Stable-dep-of: 932bed412170 ("powerpc/kexec_file: fix cpus node update to FDT") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 25f95440a773b..d54188a355c9c 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -113,7 +113,8 @@ static int plpks_gen_password(void) u8 *password, consumer = PLPKS_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;
@@ -149,7 +150,9 @@ static struct plpks_auth *construct_auth(u8 consumer) if (consumer > PLPKS_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);
@@ -183,7 +186,8 @@ 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);