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tools/x86/kcpuid: Protect against faulty "max subleaf" values

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[ Upstream commit cf96ab1a96 ]

Protect against the kcpuid code parsing faulty max subleaf numbers
through a min() expression.  Thus, ensuring that max_subleaf will always
be ≤ MAX_SUBLEAF_NUM.

Use "u32" for the subleaf numbers since kcpuid is compiled with -Wextra,
which includes signed/unsigned comparisons warnings.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-5-darwi@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ahmed S. Darwish 2024-07-18 15:47:44 +02:00 committed by Greg Kroah-Hartman
parent dfec74d685
commit 198314189f
1 changed files with 5 additions and 7 deletions
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12
tools/arch/x86/kcpuid/kcpuid.c
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@ -7,7 +7,8 @@
#include <string.h>
#include <getopt.h>
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#define min(a, b) (((a) < (b)) ? (a) : (b))
typedef unsigned int u32;
typedef unsigned long long u64;
@ -203,12 +204,9 @@ static void raw_dump_range(struct cpuid_range *range)
#define MAX_SUBLEAF_NUM 32
struct cpuid_range *setup_cpuid_range(u32 input_eax)
{
u32 max_func, idx_func;
int subleaf;
u32 max_func, idx_func, subleaf, max_subleaf;
u32 eax, ebx, ecx, edx, f = input_eax;
struct cpuid_range *range;
u32 eax, ebx, ecx, edx;
u32 f = input_eax;
int max_subleaf;
bool allzero;
eax = input_eax;
@ -254,7 +252,7 @@ struct cpuid_range *setup_cpuid_range(u32 input_eax)
* others have to be tried (0xf)
*/
if (f == 0x7 || f == 0x14 || f == 0x17 || f == 0x18)
max_subleaf = (eax & 0xff) + 1;
max_subleaf = min((eax & 0xff) + 1, max_subleaf);
if (f == 0xb)
max_subleaf = 2;