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From: "tip-bot2 for Andy Lutomirski" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	stable@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: [tip: x86/urgent] x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls
Date: Sat, 06 Mar 2021 10:44:09 -0000	[thread overview]
Message-ID: <161502744987.398.7050665815456355997.tip-bot2@tip-bot2> (raw)
In-Reply-To: <8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org>

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     e59ba7bf71a09e474198741563e0e587ae43d1c7
Gitweb:        https://git.kernel.org/tip/e59ba7bf71a09e474198741563e0e587ae43d1c7
Author:        Andy Lutomirski <luto@kernel.org>
AuthorDate:    Thu, 04 Mar 2021 11:05:54 -08:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Sat, 06 Mar 2021 11:37:00 +01:00

x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls

On a 32-bit fast syscall that fails to read its arguments from user
memory, the kernel currently does syscall exit work but not
syscall entry work.  This confuses audit and ptrace.  For example:

    $ ./tools/testing/selftests/x86/syscall_arg_fault_32
    ...
    strace: pid 264258: entering, ptrace_syscall_info.op == 2
    ...

This is a minimal fix intended for ease of backporting.  A more
complete cleanup is coming.

Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.1614884673.git.luto@kernel.org

---
 arch/x86/entry/common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a2433ae..4efd39a 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -128,7 +128,8 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
 		regs->ax = -EFAULT;
 
 		instrumentation_end();
-		syscall_exit_to_user_mode(regs);
+		local_irq_disable();
+		irqentry_exit_to_user_mode(regs);
 		return false;
 	}
 

  parent reply	other threads:[~2021-03-06 10:44 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04 19:05 [PATCH v3 00/11] kentry: A stable bugfix and a bunch of improvements Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 01/11] x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls Andy Lutomirski
2021-03-05 10:16   ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2021-03-06 10:44   ` tip-bot2 for Andy Lutomirski [this message]
2021-03-06 12:18   ` tip-bot2 for Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 02/11] kentry: Rename irqentry to kentry Andy Lutomirski
2021-03-08  9:45   ` Mark Rutland
2021-03-04 19:05 ` [PATCH v3 03/11] x86/dumpstack: Remove unnecessary range check fetching opcode bytes Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 04/11] x86/kthread,dumpstack: Set task_pt_regs->cs.RPL=3 for kernel threads Andy Lutomirski
2021-03-04 20:19   ` Ira Weiny
2021-03-04 19:05 ` [PATCH v3 05/11] x86/entry: Convert ret_from_fork to C Andy Lutomirski
2021-03-05  0:55   ` Brian Gerst
2021-03-04 19:05 ` [PATCH v3 06/11] kentry: Simplify the common syscall API Andy Lutomirski
2021-03-08  9:49   ` Mark Rutland
2021-03-04 19:06 ` [PATCH v3 07/11] kentry: Make entry/exit_to_user_mode() arm64-only Andy Lutomirski
2021-03-08 10:06   ` Mark Rutland
2021-03-14  1:18     ` Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 08/11] entry: Make CONFIG_DEBUG_ENTRY available outside x86 Andy Lutomirski
2021-03-08 10:13   ` Mark Rutland
2021-03-29 11:50     ` Sven Schnelle
2021-03-04 19:06 ` [PATCH v3 09/11] kentry: Add debugging checks for proper kentry API usage Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 10/11] kentry: Check that syscall entries and syscall exits match Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 11/11] kentry: Verify kentry state in instrumentation_begin/end() Andy Lutomirski

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