The third argument of strscpy() is optional and can be left away iff
the destination is an array and the maximum size of the copy is the
size of destination.
Remove the third argument for those cases where this is possible.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Use asm_inline for all inline assemblies which make use of the EX_TABLE or
ALTERNATIVE macros.
These macros expand to many lines and the compiler assumes the number of
lines within an inline assembly is the same as the number of instructions
within an inline assembly. This has an effect on inlining and loop
unrolling decisions.
In order to avoid incorrect assumptions use asm_inline, which tells the
compiler that an inline assembly has the smallest possible size.
In order to avoid confusion when asm_inline should be used or not, since a
couple of inline assemblies are quite large: the rule is to always use
asm_inline whenever the EX_TABLE or ALTERNATIVE macro is used. In specific
cases there may be reasons to not follow this guideline, but that should
be documented with the corresponding code.
Using the inline qualifier everywhere has only a small effect on the kernel
image size:
add/remove: 0/10 grow/shrink: 19/8 up/down: 1492/-1858 (-366)
The only location where this seems to matter is load_unaligned_zeropad()
from word-at-a-time.h where the compiler inlines more functions within the
dcache code, which is indeed code where performance matters.
Suggested-by: Juergen Christ <jchrist@linux.ibm.com>
Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Building cert_store.o with W=1 reveals this bug:
CC arch/s390/kernel/cert_store.o
arch/s390/kernel/cert_store.c:443:45: warning: ‘sprintf’ may write a terminating nul past the end of the destination [-Wformat-overflow=]
443 | sprintf(desc + name_len, ":%04u:%08u", vce->vce_hdr.vc_index, cs_token);
| ^
arch/s390/kernel/cert_store.c:443:9: note: ‘sprintf’ output between 15 and 18 bytes into a destination of size 15
443 | sprintf(desc + name_len, ":%04u:%08u", vce->vce_hdr.vc_index, cs_token);
Fix this by using the correct maximum width for each integer component
in both buffer length calculation and format string. Also switch to
using snprintf() to guard against potential future changes to the
integer range of each component.
Fixes: 8cf57d7217 ("s390: add support for user-defined certificates")
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Enable receiving the user-defined certificates from the s390x
hypervisor via new diagnose 0x320 calls, and make them available to the
Linux root user as 'cert_store_key' type keys in a so-called
'cert_store' keyring.
New user-space interfaces:
/sys/firmware/cert_store/refresh
Writing to this attribute re-fetches certificates via DIAG 0x320
/sys/firmware/cert_store/cs_status
Reading from this attribute returns either of:
"uninitialized"
If no certificate has been retrieved yet
"ok"
If certificates have been successfully retrieved
"failed (<number>)"
If certificate retrieval failed with reason code <number>
New debug trace areas:
/sys/kernel/debug/s390dbf/cert_store_msg
/sys/kernel/debug/s390dbf/cert_store_hexdump
Usage example:
To initiate request for certificates available to the system as root:
$ echo 1 > /sys/firmware/cert_store/refresh
Upon success the '/sys/firmware/cert_store/cs_status' contains
the value 'ok'.
$ cat /sys/firmware/cert_store/cs_status
ok
Get the ID of the keyring 'cert_store':
$ keyctl search @us keyring cert_store
OR
$ keyctl link @us @s; keyctl request keyring cert_store
Obtain list of IDs of certificates:
$ keyctl rlist <cert_store keyring ID>
Display certificate content as hex-dump:
$ keyctl read <certificate ID>
Read certificate contents as binary data:
$ keyctl pipe <certificate ID> >cert_data
Display certificate description:
$ keyctl describe <certificate ID>
The certificate description has the following format:
<64 bytes certificate name in EBCDIC> ':'
<certificate index as obtained from hypervisor> ':'
<certificate store token obtained from hypervisor>
The certificate description in /proc/keys has certificate name
represented in ASCII.
Users can read but cannot update the content of the certificate.
Signed-off-by: Anastasia Eskova <anastasia.eskova@ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
