riscv: ptrace: reject CFI regset access when extensions are absent

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riscv_cfi_get() and riscv_cfi_set() do not check whether the Zicfilp
or Zicfiss extensions are present. On systems without them,
PTRACE_GETREGSET on REGSET_CFI still succeeds and returns a zeroed
user_cfi_state, misleading debuggers into believing the register set
is available, and PTRACE_SETREGSET silently accepts writes that have
no effect (e.g. clearing SR_ELP).

Reject the access with -EINVAL when neither branch landing pads nor
shadow stack is available to userspace, using the same availability
helpers as the prctl path.

Fixes: 2af7c9cf02 ("riscv/ptrace: expose riscv CFI status and state via ptrace and in core files")
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Link: https://patch.msgid.link/20260820063233.2567-1-cp0613@linux.alibaba.com
Cc: stable@vger.kernel.org
Signed-off-by: Paul Walmsley <pjw@kernel.org>

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Chen Pei 2026-08-20 14:32:33 +08:00 • committed by Paul Walmsley

parent 07e23d0b6f

commit adadf6df0b

1 changed files with 6 additions and 0 deletions

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arch/riscv/kernel/ptrace.c

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