linux-kernel - [PATCH v3 6/6] x86/uaccess: Converge [__]get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d8fcb2f521c5186639d1cfd296ddc672d9c224f4.1730166635.git.jpoimboe@kernel.org>
Date: Mon, 28 Oct 2024 18:56:19 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
	Waiman Long <longman@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	linuxppc-dev@...ts.ozlabs.org,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Mark Rutland <mark.rutland@....com>,
	"Kirill A . Shutemov" <kirill@...temov.name>
Subject: [PATCH v3 6/6] x86/uaccess: Converge [__]get_user() implementations

The x86 implementations of get_user() and __get_user() are now
identical.  Merge their implementations and make the __get_user()
implementations aliases of their get_user() counterparts.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/lib/getuser.S | 58 +++++++++---------------------------------
 1 file changed, 12 insertions(+), 46 deletions(-)

diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index 7da4fc75eba9..6f4dcb80dd46 100644
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -103,53 +103,19 @@ SYM_FUNC_START(__get_user_8)
 SYM_FUNC_END(__get_user_8)
 EXPORT_SYMBOL(__get_user_8)
 
-/* .. and the same for __get_user, just without the range checks */
-SYM_FUNC_START(__get_user_nocheck_1)
-	mask_user_address size=1
-	ASM_STAC
-	UACCESS movzbl (%_ASM_AX),%edx
-	xor %eax,%eax
-	ASM_CLAC
-	RET
-SYM_FUNC_END(__get_user_nocheck_1)
-EXPORT_SYMBOL(__get_user_nocheck_1)
-
-SYM_FUNC_START(__get_user_nocheck_2)
-	mask_user_address size=2
-	ASM_STAC
-	UACCESS movzwl (%_ASM_AX),%edx
-	xor %eax,%eax
-	ASM_CLAC
-	RET
-SYM_FUNC_END(__get_user_nocheck_2)
-EXPORT_SYMBOL(__get_user_nocheck_2)
-
-SYM_FUNC_START(__get_user_nocheck_4)
-	mask_user_address size=4
-	ASM_STAC
-	UACCESS movl (%_ASM_AX),%edx
-	xor %eax,%eax
-	ASM_CLAC
-	RET
-SYM_FUNC_END(__get_user_nocheck_4)
-EXPORT_SYMBOL(__get_user_nocheck_4)
-
-SYM_FUNC_START(__get_user_nocheck_8)
-	mask_user_address size=8
-	ASM_STAC
-#ifdef CONFIG_X86_64
-	UACCESS movq (%_ASM_AX),%rdx
-#else
-	xor %ecx,%ecx
-	UACCESS movl (%_ASM_AX),%edx
-	UACCESS movl 4(%_ASM_AX),%ecx
-#endif
-	xor %eax,%eax
-	ASM_CLAC
-	RET
-SYM_FUNC_END(__get_user_nocheck_8)
-EXPORT_SYMBOL(__get_user_nocheck_8)
+/*
+ * On x86-64, get_user() does address masking rather than a conditional bounds
+ * check so there's no functional difference compared to __get_user().
+ */
+SYM_FUNC_ALIAS(__get_user_nocheck_1, __get_user_1);
+SYM_FUNC_ALIAS(__get_user_nocheck_2, __get_user_2);
+SYM_FUNC_ALIAS(__get_user_nocheck_4, __get_user_4);
+SYM_FUNC_ALIAS(__get_user_nocheck_8, __get_user_8);
 
+EXPORT_SYMBOL(__get_user_nocheck_1);
+EXPORT_SYMBOL(__get_user_nocheck_2);
+EXPORT_SYMBOL(__get_user_nocheck_4);
+EXPORT_SYMBOL(__get_user_nocheck_8);
 
 SYM_CODE_START_LOCAL(__get_user_handle_exception)
 	ASM_CLAC
-- 
2.47.0