From: Liam Howlett <liam.howlett@oracle.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Julien Grall <julien.grall@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Liam Howlett <liam.howlett@oracle.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: [PATCH 2/3] arm64: signal: sigreturn() and rt_sigreturn() sometime returns the wrong signals
Date: Tue, 20 Apr 2021 16:50:13 +0000 [thread overview]
Message-ID: <20210420165001.3790670-2-Liam.Howlett@Oracle.com> (raw)
In-Reply-To: <20210420165001.3790670-1-Liam.Howlett@Oracle.com>
arm64_notify_segfault() was used to force a SIGSEGV in all error cases
in sigreturn() and rt_sigreturn() to avoid writing a new sig handler.
There is now a better sig handler to use which does not search the VMA
address space and return a slightly incorrect error code. Restore the
older and correct si_code of SI_KERNEL by using arm64_notify_die(). In
the case of !access_ok(), simply return SIGSEGV with si_code
SEGV_ACCERR.
This change requires exporting arm64_notfiy_die() to the arm64 traps.h
Fixes: f71016a8a8c5 (arm64: signal: Call arm64_notify_segfault when
failing to deliver signal)
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
arch/arm64/include/asm/traps.h | 2 ++
arch/arm64/kernel/signal.c | 8 ++++++--
arch/arm64/kernel/signal32.c | 18 ++++++++++++++----
3 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 54f32a0675df..9b76144fcba6 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -29,6 +29,8 @@ void arm64_notify_segfault(unsigned long addr);
void arm64_force_sig_fault(int signo, int code, unsigned long far, const char *str);
void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, const char *str);
void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far, const char *str);
+void arm64_notify_die(const char *str, struct pt_regs *regs, int signo,
+ int sicode, unsigned long far, int err);
/*
* Move regs->pc to next instruction and do necessary setup before it
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 6237486ff6bb..9fde6dc760c3 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -544,7 +544,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
frame = (struct rt_sigframe __user *)regs->sp;
if (!access_ok(frame, sizeof (*frame)))
- goto badframe;
+ goto e_access;
if (restore_sigframe(regs, frame))
goto badframe;
@@ -555,7 +555,11 @@ SYSCALL_DEFINE0(rt_sigreturn)
return regs->regs[0];
badframe:
- arm64_notify_segfault(regs->sp);
+ arm64_notify_die("Bad frame", regs, SIGSEGV, SI_KERNEL, regs->sp, 0);
+ return 0;
+
+e_access:
+ force_signal_inject(SIGSEGV, SEGV_ACCERR, regs->sp, 0);
return 0;
}
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 2f507f565c48..af8b6c0eb8aa 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -248,7 +248,7 @@ COMPAT_SYSCALL_DEFINE0(sigreturn)
frame = (struct compat_sigframe __user *)regs->compat_sp;
if (!access_ok(frame, sizeof (*frame)))
- goto badframe;
+ goto e_access;
if (compat_restore_sigframe(regs, frame))
goto badframe;
@@ -256,7 +256,12 @@ COMPAT_SYSCALL_DEFINE0(sigreturn)
return regs->regs[0];
badframe:
- arm64_notify_segfault(regs->compat_sp);
+ arm64_notify_die("Bad frame", regs, SIGSEGV, SI_KERNEL,
+ regs->compat_sp, 0);
+ return 0;
+
+e_access:
+ force_signal_inject(SIGSEGV, SEGV_ACCERR, regs->compat_sp, 0);
return 0;
}
@@ -279,7 +284,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
frame = (struct compat_rt_sigframe __user *)regs->compat_sp;
if (!access_ok(frame, sizeof (*frame)))
- goto badframe;
+ goto e_access;
if (compat_restore_sigframe(regs, &frame->sig))
goto badframe;
@@ -290,7 +295,12 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
return regs->regs[0];
badframe:
- arm64_notify_segfault(regs->compat_sp);
+ arm64_notify_die("Bad frame", regs, SIGSEGV, SI_KERNEL,
+ regs->compat_sp, 0);
+ return 0;
+
+e_access:
+ force_signal_inject(SIGSEGV, SEGV_ACCERR, regs->compat_sp, 0);
return 0;
}
--
2.30.2
next prev parent reply other threads:[~2021-04-20 16:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 16:50 [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Liam Howlett
2021-04-20 16:50 ` Liam Howlett [this message]
2021-04-22 12:48 ` [PATCH 2/3] arm64: signal: sigreturn() and rt_sigreturn() sometime returns the wrong signals Will Deacon
2021-04-22 18:22 ` Eric W. Biederman
2021-04-22 19:24 ` Liam Howlett
2021-04-23 18:17 ` Eric W. Biederman
2021-04-23 20:03 ` Liam Howlett
2021-04-29 17:52 ` Eric W. Biederman
2021-04-30 18:48 ` Liam Howlett
2021-04-30 19:57 ` Eric W. Biederman
2021-04-30 20:31 ` Liam Howlett
2021-04-20 16:50 ` [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code Liam Howlett
2021-04-22 12:53 ` Will Deacon
2021-04-22 18:56 ` Liam Howlett
2021-04-20 21:22 ` [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation kernel test robot
2021-04-21 15:47 ` Liam Howlett
2021-04-22 12:59 ` Will Deacon
2021-04-23 1:00 ` Liam Howlett
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