The sysfs core now allows instances of 'struct bin_attribute' to be moved into read-only memory. Make use of that to protect them against accidental or malicious modifications. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20241216-sysfs-const-bin_attr-powerpc-v1-2-bbed8906f476@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The setup functions are only called during the init phase of the kernel. They can be discarded and their memory reused after that. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20241216-sysfs-const-bin_attr-powerpc-v1-1-bbed8906f476@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
'struct kobj_type' is not modified. It is only used in kobject_init_and_add()/kobject_init() which takes a 'const struct kobj_type *ktype' parameter. Constifying this structure moves some data to a read-only section, so increase over all security. On a x86_64, compiled with ppc64 defconfig: Before: ====== text data bss dec hex filename 7145 606 0 7751 1e47 arch/powerpc/kernel/cacheinfo.o 3663 384 16 4063 fdf arch/powerpc/kernel/secvar-sysfs.o After: ====== text data bss dec hex filename 7193 558 0 7751 1e47 arch/powerpc/kernel/cacheinfo.o 3663 384 16 4063 fdf arch/powerpc/kernel/secvar-sysfs.o Signed-off-by: Huang Xiaojia <huangxiaojia2@huawei.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240826150957.3500237-1-huangxiaojia2@huawei.com
If attempting to read the size or data attributes of a non-existent variable (which will be possible after a later patch to expose the PLPKS via the secvar interface), don't spam the kernel log with error messages. Only print errors for return codes that aren't ENOENT. Reported-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-14-ajd@linux.ibm.com
Due to sysfs constraints, when writing to a variable, we can only handle writes of up to PAGE_SIZE. It's possible that the maximum object size is larger than PAGE_SIZE, in which case, print a warning on boot so that the user is aware. Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-13-ajd@linux.ibm.com
Currently, the list of variables is populated by calling secvar_ops->get_next() repeatedly, which is explicitly modelled on the OPAL API (including the keylen parameter). For the upcoming PLPKS backend, we have a static list of variable names. It is messy to fit that into get_next(), so instead, let the backend put a NULL-terminated array of variable names into secvar_ops->var_names, which will be used if get_next() is undefined. Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-12-ajd@linux.ibm.com
The forthcoming pseries consumer of the secvar API wants to expose a number of config variables. Allowing secvar implementations to provide their own sysfs attributes makes it easy for consumers to expose what they need to. This is not being used by the OPAL secvar implementation at present, and the config directory will not be created if no attributes are set. Signed-off-by: Russell Currey <ruscur@russell.cc> Co-developed-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-11-ajd@linux.ibm.com
Remove unnecessary prefixes from error messages in secvar_sysfs_init() (the file defines pr_fmt, so putting "secvar:" in every message is unnecessary). Make capitalisation and punctuation more consistent. Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-10-ajd@linux.ibm.com
Currently the max object size is handled in the core secvar code with an entirely OPAL-specific implementation, so create a new max_size() op and move the existing implementation into the powernv platform. Should be no functional change. Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-9-ajd@linux.ibm.com
The code that handles the format string in secvar-sysfs.c is entirely OPAL specific, so create a new "format" op in secvar_operations to make the secvar code more generic. No functional change. Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230210080401.345462-8-ajd@linux.ibm.com