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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>, Rich Felker <dalias@libc.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>,
	ysato@users.sourceforge.jp, catalin.marinas@arm.com,
	bcain@quicinc.com, akpm@linux-foundation.org, guoren@kernel.org,
	wangkefeng.wang@huawei.com, linux-sh@vger.kernel.org
Subject: [PATCH AUTOSEL 5.10 15/15] sh: sanitize the flags on sigreturn
Date: Sun, 19 Mar 2023 20:55:59 -0400	[thread overview]
Message-ID: <20230320005559.1429040-15-sashal@kernel.org> (raw)
In-Reply-To: <20230320005559.1429040-1-sashal@kernel.org>

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit 573b22ccb7ce9ab7f0539a2e11a9d3609a8783f5 ]

We fetch %SR value from sigframe; it might have been modified by signal
handler, so we can't trust it with any bits that are not modifiable in
user mode.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/sh/include/asm/processor_32.h | 1 +
 arch/sh/kernel/signal_32.c         | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index aa92cc933889d..6c7966e627758 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -50,6 +50,7 @@
 #define SR_FD		0x00008000
 #define SR_MD		0x40000000
 
+#define SR_USER_MASK	0x00000303	// M, Q, S, T bits
 /*
  * DSP structure and data
  */
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index dd3092911efad..dc13702003f0f 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -115,6 +115,7 @@ static int
 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 {
 	unsigned int err = 0;
+	unsigned int sr = regs->sr & ~SR_USER_MASK;
 
 #define COPY(x)		err |= __get_user(regs->x, &sc->sc_##x)
 			COPY(regs[1]);
@@ -130,6 +131,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p
 	COPY(sr);	COPY(pc);
 #undef COPY
 
+	regs->sr = (regs->sr & SR_USER_MASK) | sr;
+
 #ifdef CONFIG_SH_FPU
 	if (boot_cpu_data.flags & CPU_HAS_FPU) {
 		int owned_fp;
-- 
2.39.2


      parent reply	other threads:[~2023-03-20  1:06 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-20  0:55 [PATCH AUTOSEL 5.10 01/15] HID: uhid: Over-ride the default maximum data buffer value with our own Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 02/15] HID: cp2112: Fix driver not registering GPIO IRQ chip as threaded Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 03/15] ca8210: fix mac_len negative array access Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 04/15] HID: intel-ish-hid: ipc: Fix potential use-after-free in work function Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 05/15] m68k: Only force 030 bus error if PC not in exception table Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 06/15] selftests/bpf: check that modifier resolves after pointer Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 07/15] scsi: target: iscsi: Fix an error message in iscsi_check_key() Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 08/15] scsi: hisi_sas: Check devm_add_action() return value Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 09/15] scsi: ufs: core: Add soft dependency on governor_simpleondemand Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 10/15] scsi: lpfc: Avoid usage of list iterator variable after loop Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 11/15] scsi: storvsc: Handle BlockSize change in Hyper-V VHD/VHDX file Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 12/15] platform/x86: ISST: Increase range of valid mail box commands Sasha Levin
2023-03-20 13:50   ` Pavel Machek
2023-03-27 11:25     ` Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 13/15] net: usb: cdc_mbim: avoid altsetting toggling for Telit FE990 Sasha Levin
2023-03-20  0:55 ` [PATCH AUTOSEL 5.10 14/15] net: usb: qmi_wwan: add Telit 0x1080 composition Sasha Levin
2023-03-20  0:55 ` Sasha Levin [this message]

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