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Revert "ANDROID: security,perf: Allow further restriction of perf_event_open"

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Unfork Android.

This reverts commit 8e5e42d5ae.

Perf_event_paranoid=3 is no longer needed on Android. Access control
of perf events is now done by selinux. See:
https://patchwork.kernel.org/patch/11185793/

Bug: 120445712
Bug: 137092007
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: Iba493424174b30baff460caaa25a54a472c87bd4
This commit is contained in:
Jeff Vander Stoep 2020-01-23 09:51:14 +01:00 committed by Alistair Delva
parent c3f91ecb17
commit 025a1ee618
6 changed files with 1 additions and 27 deletions
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4
Documentation/sysctl/kernel.txt
View file

@ -693,8 +693,7 @@ allowed to execute.
perf_event_paranoid:
Controls use of the performance events system by unprivileged
users (without CAP_SYS_ADMIN). The default value is 3 if
CONFIG_SECURITY_PERF_EVENTS_RESTRICT is set, or 2 otherwise.
users (without CAP_SYS_ADMIN). The default value is 2.
-1: Allow use of (almost) all events by all users
Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
@ -702,7 +701,6 @@ CONFIG_SECURITY_PERF_EVENTS_RESTRICT is set, or 2 otherwise.
Disallow raw tracepoint access by users without CAP_SYS_ADMIN
>=1: Disallow CPU event access by users without CAP_SYS_ADMIN
>=2: Disallow kernel profiling by users without CAP_SYS_ADMIN
>=3: Disallow all event access by users without CAP_SYS_ADMIN
==============================================================

1
arch/arm64/configs/gki_defconfig
View file

@ -464,7 +464,6 @@ CONFIG_NLS_MAC_INUIT=y
CONFIG_NLS_MAC_ROMANIAN=y
CONFIG_NLS_MAC_TURKISH=y
CONFIG_NLS_UTF8=y
CONFIG_SECURITY_PERF_EVENTS_RESTRICT=y
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
CONFIG_HARDENED_USERCOPY=y

1
arch/x86/configs/gki_defconfig
View file

@ -401,7 +401,6 @@ CONFIG_NLS_MAC_INUIT=y
CONFIG_NLS_MAC_ROMANIAN=y
CONFIG_NLS_MAC_TURKISH=y
CONFIG_NLS_UTF8=y
CONFIG_SECURITY_PERF_EVENTS_RESTRICT=y
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
CONFIG_HARDENED_USERCOPY=y

5
include/linux/perf_event.h
View file

@ -1206,11 +1206,6 @@ int perf_event_max_stack_handler(struct ctl_table *table, int write,
#define PERF_SECURITY_KERNEL 2
#define PERF_SECURITY_TRACEPOINT 3
static inline bool perf_paranoid_any(void)
{
return sysctl_perf_event_paranoid > 2;
}
static inline int perf_is_paranoid(void)
{
return sysctl_perf_event_paranoid > -1;

8
kernel/events/core.c
View file

@ -397,13 +397,8 @@ static cpumask_var_t perf_online_mask;
* 0 - disallow raw tracepoint access for unpriv
* 1 - disallow cpu events for unpriv
* 2 - disallow kernel profiling for unpriv
* 3 - disallow all unpriv perf event use
*/
#ifdef CONFIG_SECURITY_PERF_EVENTS_RESTRICT
int sysctl_perf_event_paranoid __read_mostly = 3;
#else
int sysctl_perf_event_paranoid __read_mostly = 2;
#endif
/* Minimum for 512 kiB + 1 user control page */
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
@ -10550,9 +10545,6 @@ SYSCALL_DEFINE5(perf_event_open,
if (flags & ~PERF_FLAG_ALL)
return -EINVAL;
if (perf_paranoid_any() && !capable(CAP_SYS_ADMIN))
return -EACCES;
/* Do we allow access to perf_event_open(2) ? */
err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
if (err)

9
security/Kconfig
View file

@ -18,15 +18,6 @@ config SECURITY_DMESG_RESTRICT
If you are unsure how to answer this question, answer N.
config SECURITY_PERF_EVENTS_RESTRICT
bool "Restrict unprivileged use of performance events"
depends on PERF_EVENTS
help
If you say Y here, the kernel.perf_event_paranoid sysctl
will be set to 3 by default, and no unprivileged use of the
perf_event_open syscall will be permitted unless it is
changed.
config SECURITY
bool "Enable different security models"
depends on SYSFS