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Revision 72cd652b73dd77df6f26bd450e804ee29232669f authored by Athira Rajeev on 05 September 2022, 14:19:28 UTC, committed by Arnaldo Carvalho de Melo on 06 September 2022, 12:45:23 UTC 
perf affinity: Fix out of bound access to "sched_cpus" mask
 
The affinity code in "affinity_set" function access array named
"sched_cpus". The size for this array is allocated in affinity_setup
function which is nothing but value from get_cpu_set_size. This is used
to contain the cpumask value for each cpu.

While setting bit for each cpu, it calls "set_bit" function which access
index in sched_cpus array.  If we provide a command-line option to -C
which is more than the number of CPU's present in the system, the
set_bit could access an array member which is out-of the array size.
This is because currently, there is no boundary check for the CPU.  This
will result in seg fault:

<<>>
   ./perf stat -C 12323431 ls
  Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS
  Segmentation fault (core dumped)
<<>>

Fix this by adding boundary check for the array.

After the fix from powerpc system:

<<>>
  ./perf stat -C 12323431 ls 1>out
  Perf can support 2048 CPUs. Consider raising MAX_NR_CPUS

   Performance counter stats for 'CPU(s) 12323431':

     <not supported> msec cpu-clock
     <not supported>      context-switches
     <not supported>      cpu-migrations
     <not supported>      page-faults
     <not supported>      cycles
     <not supported>      instructions
     <not supported>      branches
     <not supported>      branch-misses

         0.001192373 seconds time elapsed
<<>>

Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20220905141929.7171-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 parent f0c86a2
Raw File
audit.c 
// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/types.h>
#include <linux/audit.h>
#include <asm/unistd.h>

static unsigned dir_class[] = {
#include <asm-generic/audit_dir_write.h>
~0U
};

static unsigned read_class[] = {
#include <asm-generic/audit_read.h>
~0U
};

static unsigned write_class[] = {
#include <asm-generic/audit_write.h>
~0U
};

static unsigned chattr_class[] = {
#include <asm-generic/audit_change_attr.h>
~0U
};

static unsigned signal_class[] = {
#include <asm-generic/audit_signal.h>
~0U
};

int audit_classify_arch(int arch)
{
	if (audit_is_compat(arch))
		return 1;
	else
		return 0;
}

int audit_classify_syscall(int abi, unsigned syscall)
{
	if (audit_is_compat(abi))
		return audit_classify_compat_syscall(abi, syscall);

	switch(syscall) {
#ifdef __NR_open
	case __NR_open:
		return AUDITSC_OPEN;
#endif
#ifdef __NR_openat
	case __NR_openat:
		return AUDITSC_OPENAT;
#endif
#ifdef __NR_socketcall
	case __NR_socketcall:
		return AUDITSC_SOCKETCALL;
#endif
#ifdef __NR_execveat
	case __NR_execveat:
#endif
	case __NR_execve:
		return AUDITSC_EXECVE;
#ifdef __NR_openat2
	case __NR_openat2:
		return AUDITSC_OPENAT2;
#endif
	default:
		return AUDITSC_NATIVE;
	}
}

static int __init audit_classes_init(void)
{
#ifdef CONFIG_AUDIT_COMPAT_GENERIC
	audit_register_class(AUDIT_CLASS_WRITE_32, compat_write_class);
	audit_register_class(AUDIT_CLASS_READ_32, compat_read_class);
	audit_register_class(AUDIT_CLASS_DIR_WRITE_32, compat_dir_class);
	audit_register_class(AUDIT_CLASS_CHATTR_32, compat_chattr_class);
	audit_register_class(AUDIT_CLASS_SIGNAL_32, compat_signal_class);
#endif
	audit_register_class(AUDIT_CLASS_WRITE, write_class);
	audit_register_class(AUDIT_CLASS_READ, read_class);
	audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class);
	audit_register_class(AUDIT_CLASS_CHATTR, chattr_class);
	audit_register_class(AUDIT_CLASS_SIGNAL, signal_class);
	return 0;
}

__initcall(audit_classes_init);
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