diff options
author | Benjamin Gray <bgray@linux.ibm.com> | 2023-06-19 10:36:26 +0300 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-06-19 10:36:27 +0300 |
commit | 97228ca375c78bfd960767dcd4919c981add306f (patch) | |
tree | 62d0c55e78da7dcd3c727821f3c07751c8cc6ce7 /include/uapi | |
parent | 884ad5c52da253e5d38f947cd8d1d9412a47429c (diff) | |
download | linux-97228ca375c78bfd960767dcd4919c981add306f.tar.xz |
powerpc/ptrace: Expose HASHKEYR register to ptrace
The HASHKEYR register contains a secret per-process key to enable unique
hashes per process. In general it should not be exposed to userspace
at all and a regular process has no need to know its key.
However, checkpoint restore in userspace (CRIU) functionality requires
that a process be able to set the HASHKEYR of another process, otherwise
existing hashes on the stack would be invalidated by a new random key.
Exposing HASHKEYR in this way also makes it appear in core dumps, which
is a security concern. Multiple threads may share a key, for example
just after a fork() call, where the kernel cannot know if the child is
going to return back along the parent's stack. If such a thread is
coerced into making a core dump, then the HASHKEYR value will be
readable and able to be used against all other threads sharing that key,
effectively undoing any protection offered by hashst/hashchk.
Therefore we expose HASHKEYR to ptrace when CONFIG_CHECKPOINT_RESTORE is
enabled, providing a choice of increased security or migratable ROP
protected processes. This is similar to how ARM exposes its PAC keys.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616034846.311705-8-bgray@linux.ibm.com
Diffstat (limited to 'include/uapi')
-rw-r--r-- | include/uapi/linux/elf.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index cfa31f1eb5d7..b705b301d88f 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -404,6 +404,7 @@ typedef struct elf64_shdr { #define NT_PPC_TM_CDSCR 0x10f /* TM checkpointed Data Stream Control Register */ #define NT_PPC_PKEY 0x110 /* Memory Protection Keys registers */ #define NT_PPC_DEXCR 0x111 /* PowerPC DEXCR registers */ +#define NT_PPC_HASHKEYR 0x112 /* PowerPC HASHKEYR register */ #define NT_386_TLS 0x200 /* i386 TLS slots (struct user_desc) */ #define NT_386_IOPERM 0x201 /* x86 io permission bitmap (1=deny) */ #define NT_X86_XSTATE 0x202 /* x86 extended state using xsave */ |