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Subject[PATCH] KEYS: correct alignment of system_certificate_list content in assembly file
Date
Apart from data-type specific alignment constraints, there are also
architecture-specific alignment requirements.
For example, on s390 symbols must be on even addresses implying a 2-byte
alignment. If the system_certificate_list_end symbol is on an odd address
and if this address is loaded, the least-significant bit is ignored. As a
result, the load_system_certificate_list() fails to load the certificates
because of a wrong certificate length calculation.

To be safe, align system_certificate_list on an 8-byte boundary. Also improve
the length calculation of the system_certificate_list content. Introduce a
system_certificate_list_size (8-byte aligned because of unsigned long) variable
that stores the length. Let the linker calculate this size by introducing
a start and end label for the certificate content.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
---
kernel/system_certificates.S | 14 ++++++++++++--
kernel/system_keyring.c | 4 ++--
2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/kernel/system_certificates.S b/kernel/system_certificates.S
index 4aef390..3e9868d47 100644
--- a/kernel/system_certificates.S
+++ b/kernel/system_certificates.S
@@ -3,8 +3,18 @@

__INITRODATA

+ .align 8
.globl VMLINUX_SYMBOL(system_certificate_list)
VMLINUX_SYMBOL(system_certificate_list):
+__cert_list_start:
.incbin "kernel/x509_certificate_list"
- .globl VMLINUX_SYMBOL(system_certificate_list_end)
-VMLINUX_SYMBOL(system_certificate_list_end):
+__cert_list_end:
+
+ .align 8
+ .globl VMLINUX_SYMBOL(system_certificate_list_size)
+VMLINUX_SYMBOL(system_certificate_list_size):
+#ifdef CONFIG_64BIT
+ .quad __cert_list_end - __cert_list_start
+#else
+ .long __cert_list_end - __cert_list_start
+#endif
diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c
index 564dd93..52ebc70 100644
--- a/kernel/system_keyring.c
+++ b/kernel/system_keyring.c
@@ -22,7 +22,7 @@ struct key *system_trusted_keyring;
EXPORT_SYMBOL_GPL(system_trusted_keyring);

extern __initconst const u8 system_certificate_list[];
-extern __initconst const u8 system_certificate_list_end[];
+extern __initconst const unsigned long system_certificate_list_size;

/*
* Load the compiled-in keys
@@ -60,8 +60,8 @@ static __init int load_system_certificate_list(void)

pr_notice("Loading compiled-in X.509 certificates\n");

- end = system_certificate_list_end;
p = system_certificate_list;
+ end = p + system_certificate_list_size;
while (p < end) {
/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
* than 256 bytes in size.
--
1.7.5.4


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