From: Paul Walmsley <pjw@kernel.org>
To: Michael Neuling <mikey@neuling.org>
Cc: pjw@kernel.org, ajones@ventanamicro.com,
akpm@linux-foundation.org, aleksa.paunovic@htecgroup.com,
alex@ghiti.fr, aou@eecs.berkeley.edu, arikalo@gmail.com,
arnd@arndb.de, bjorn@rivosinc.com, david@redhat.com,
djordje.todorovic@htecgroup.com, guoren@kernel.org,
junhui.liu@pigmoral.tech, kevin.brodsky@arm.com,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
ljs@kernel.org, namcao@linutronix.de, oleg@redhat.com,
osalvador@suse.de, palmer@dabbelt.com,
panqinglin2020@iscas.ac.cn, rppt@kernel.org,
rvishwanathan@mips.com, vishal.moola@gmail.com
Subject: Re: [PATCH v2] riscv: Fix register corruption from uninitialized cregs on error
Date: Fri, 1 May 2026 21:14:11 -0600 (MDT) [thread overview]
Message-ID: <f34b72a2-6001-3a30-1653-60b3d2e9dad0@kernel.org> (raw)
In-Reply-To: <20260501062320.2339562-1-mikey@neuling.org>
On Fri, 1 May 2026, Michael Neuling wrote:
> compat_riscv_gpr_set() calls cregs_to_regs() unconditionally, even when
> user_regset_copyin() fails. Since cregs is an uninitialized stack
> variable, a copyin failure causes uninitialized stack data to be written
> into the target task's pt_regs, corrupting its register state and
> potentially leaking kernel stack contents.
>
> compat_restore_sigcontext() has the same issue: it calls cregs_to_regs()
> even when __copy_from_user() fails, leading to the same corruption of
> the signal-returning task's register state on error.
>
> Only call cregs_to_regs() when the user copy succeeds.
>
> Fixes: 4608c159594f ("riscv: compat: ptrace: Add compat_arch_ptrace implement")
> Fixes: 7383ee05314b ("riscv: compat: signal: Add rt_frame implementation")
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Assisted-by: Cursor:claude-4.6-opus-high-thinking
Thanks very much; queued for v7.1-rc.
- Paul
next prev parent reply other threads:[~2026-05-02 3:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-09 9:11 [PATCH 0/5] riscv: Assorted bug fixes Michael Neuling
2026-04-09 9:11 ` [PATCH 1/5] riscv: errata: Fix bitwise vs logical AND in MIPS errata patching Michael Neuling
2026-05-01 2:08 ` Paul Walmsley
2026-04-09 9:11 ` [PATCH 2/5] riscv: ptrace: Fix register corruption in compat_riscv_gpr_set on error Michael Neuling
2026-05-01 2:05 ` Paul Walmsley
2026-05-01 6:21 ` Michael Neuling
2026-05-01 6:23 ` [PATCH v2] riscv: Fix register corruption from uninitialized cregs " Michael Neuling
2026-05-02 3:14 ` Paul Walmsley [this message]
2026-04-09 9:11 ` [PATCH 3/5] riscv: mm: Fix NULL pointer dereference in __set_memory Michael Neuling
2026-04-09 12:37 ` David Hildenbrand (Arm)
2026-04-10 6:23 ` Michael Neuling
2026-04-10 7:42 ` David Hildenbrand (Arm)
2026-04-10 7:53 ` Mike Rapoport
2026-04-10 7:59 ` David Hildenbrand (Arm)
2026-04-10 8:55 ` Michael Neuling
2026-04-09 9:11 ` [PATCH 4/5] riscv: mm: Fix NULL dereferences in napot hugetlb functions Michael Neuling
2026-04-09 12:36 ` David Hildenbrand (Arm)
2026-04-09 9:11 ` [PATCH 5/5] riscv: mm: Fix TOCTOU race in remove_pte_mapping Michael Neuling
2026-04-09 12:32 ` David Hildenbrand (Arm)
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