From: benjamin@sipsolutions.net
To: linux-um@lists.infradead.org
Cc: Benjamin Berg <benjamin@sipsolutions.net>
Subject: [PATCH v2 18/28] um: Store full CSGSFS and SS register from mcontext
Date: Tue, 22 Nov 2022 11:07:49 +0100 [thread overview]
Message-ID: <20221122100759.208290-19-benjamin@sipsolutions.net> (raw)
In-Reply-To: <20221122100759.208290-1-benjamin@sipsolutions.net>
From: Benjamin Berg <benjamin@sipsolutions.net>
Doing this allows using registers as retrieved from an mcontext to be
pushed to a process using PTRACE_SETREGS.
It is not entirely clear to me why CSGSFS was masked. Doing so creates
issues when using the mcontext as process state in seccomp and simply
copying the register appears to work perfectly fine for ptrace.
Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
---
arch/x86/um/os-Linux/mcontext.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/um/os-Linux/mcontext.c b/arch/x86/um/os-Linux/mcontext.c
index 49c3744cac37..81b9d1f9f4e6 100644
--- a/arch/x86/um/os-Linux/mcontext.c
+++ b/arch/x86/um/os-Linux/mcontext.c
@@ -26,7 +26,6 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
COPY(RIP);
COPY2(EFLAGS, EFL);
COPY2(CS, CSGSFS);
- regs->gp[CS / sizeof(unsigned long)] &= 0xffff;
- regs->gp[CS / sizeof(unsigned long)] |= 3;
+ regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48;
#endif
}
--
2.38.1
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next prev parent reply other threads:[~2022-11-22 10:27 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 10:07 [PATCH v2 00/28] Implement SECCOMP based userland benjamin
2022-11-22 10:07 ` [PATCH v2 01/28] um: Switch printk calls to adhere to correct coding style benjamin
2022-11-22 10:07 ` [PATCH v2 02/28] um: Declare fix_range_common as a static function benjamin
2022-11-22 10:07 ` [PATCH v2 03/28] um: Drop support for hosts without SYSEMU_SINGLESTEP support benjamin
2022-11-22 10:07 ` [PATCH v2 04/28] um: Drop NULL check from start_userspace benjamin
2022-11-22 10:07 ` [PATCH v2 05/28] um: Make errors to stop ptraced child fatal during startup benjamin
2022-11-22 10:07 ` [PATCH v2 06/28] um: Don't use vfprintf() for os_info() benjamin
2022-11-22 10:07 ` [PATCH v2 07/28] um: Do not use printk in SIGWINCH helper thread benjamin
2022-11-22 10:07 ` [PATCH v2 08/28] um: Reap winch thread if it fails benjamin
2022-11-22 10:07 ` [PATCH v2 09/28] um: Do not use printk in userspace trampoline benjamin
2022-11-22 10:07 ` [PATCH v2 10/28] um: Always inline stub functions benjamin
2022-11-22 10:07 ` [PATCH v2 11/28] um: Rely on PTRACE_SETREGSET to set FS/GS base registers benjamin
2022-11-22 10:07 ` [PATCH v2 12/28] um: Remove unused register save/restore functions benjamin
2022-11-22 10:07 ` [PATCH v2 13/28] um: Mark 32bit syscall helpers as clobbering memory benjamin
2022-11-22 10:07 ` [PATCH v2 14/28] um: Remove stub-data.h include from common-offsets.h benjamin
2022-11-22 10:07 ` [PATCH v2 15/28] um: Create signal stack memory assignment in stub_data benjamin
2022-11-22 10:07 ` [PATCH v2 16/28] um: Add generic stub_syscall6 function benjamin
2022-11-22 10:07 ` [PATCH v2 17/28] um: Rework syscall handling benjamin
2022-11-22 10:07 ` benjamin [this message]
2022-11-22 10:07 ` [PATCH v2 19/28] um: Pass full mm_id to functions creating helper processes benjamin
2022-11-22 10:07 ` [PATCH v2 20/28] um: Move faultinfo extraction into userspace routine benjamin
2022-11-22 10:07 ` [PATCH v2 21/28] um: Use struct uml_pt_regs for copy_context_skas0 benjamin
2022-11-22 10:07 ` [PATCH v2 22/28] um: Add UML_SECCOMP configuration option benjamin
2022-11-22 10:07 ` [PATCH v2 23/28] um: Add stub side of SECCOMP/futex based process handling benjamin
2022-11-22 10:07 ` [PATCH v2 24/28] um: Add helper functions to get/set state for SECCOMP benjamin
2022-11-22 10:07 ` [PATCH v2 25/28] um: Add SECCOMP support detection and initialization benjamin
2022-11-22 10:07 ` [PATCH v2 26/28] um: Die if a child dies unexpectedly in seccomp mode benjamin
2022-11-22 10:07 ` [PATCH v2 27/28] um: Implement kernel side of SECCOMP based process handling benjamin
2022-11-22 10:07 ` [PATCH v2 28/28] um: Delay flushing syscalls until the thread is restarted benjamin
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