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: <20250324142042.29010-14-darwi@linutronix.de>
Date: Mon, 24 Mar 2025 15:20:34 +0100
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	John Ogness <john.ogness@...utronix.de>,
	x86@...nel.org,
	x86-cpuid@...ts.linux.dev,
	LKML <linux-kernel@...r.kernel.org>,
	"Ahmed S. Darwish" <darwi@...utronix.de>
Subject: [PATCH v3 13/20] tools/x86/kcpuid: Consolidate index validity checks

Let index_to_cpuid_range() return a CPUID range only if the passed index
is within a CPUID range's maximum supported function on the CPU.
Returning a CPUID range that is invalid on the CPU for the passed index
does not make sense.

This also avoids repeating the "function index is within CPUID range"
checks, both at setup_cpuid_range() and index_to_func().

Signed-off-by: Ahmed S. Darwish <darwi@...utronix.de>
---
 tools/arch/x86/kcpuid/kcpuid.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index 0ba0d440482c..8f81fd66e8dd 100644
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -101,10 +101,12 @@ static char *range_to_str(struct cpuid_range *range)
 
 struct cpuid_range *index_to_cpuid_range(u32 index)
 {
+	u32 func_idx = index & CPUID_FUNCTION_MASK;
+	u32 range_idx = index & CPUID_INDEX_MASK;
 	struct cpuid_range *range;
 
 	for_each_cpuid_range(range) {
-		if (range->index == (index & CPUID_INDEX_MASK))
+		if (range->index == range_idx && (u32)range->nr > func_idx)
 			return range;
 	}
 
@@ -331,17 +333,16 @@ static void parse_line(char *line)
 	/* index/main-leaf */
 	index = strtoull(tokens[0], NULL, 0);
 
-	/* Skip line parsing if it's not covered by known ranges */
+	/*
+	 * Skip line parsing if the index is not covered by known-valid
+	 * CPUID ranges on this CPU.
+	 */
 	range = index_to_cpuid_range(index);
 	if (!range)
 		return;
 
-	/* Skip line parsing for non-existing indexes */
-	index &= CPUID_FUNCTION_MASK;
-	if ((int)index >= range->nr)
-		return;
-
 	/* Skip line parsing if the index CPUID output is all zero */
+	index &= CPUID_FUNCTION_MASK;
 	func = &range->funcs[index];
 	if (!func->nr)
 		return;
@@ -505,17 +506,13 @@ static void show_range(struct cpuid_range *range)
 
 static inline struct cpuid_func *index_to_func(u32 index)
 {
+	u32 func_idx = index & CPUID_FUNCTION_MASK;
 	struct cpuid_range *range;
-	u32 func_idx;
 
 	range = index_to_cpuid_range(index);
 	if (!range)
 		return NULL;
 
-	func_idx = index & CPUID_FUNCTION_MASK;
-	if ((func_idx + 1) > (u32)range->nr)
-		return NULL;
-
 	return &range->funcs[func_idx];
 }
 
-- 
2.48.1


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ