From 020b443d55607d7c5a3bac59b25a1aea252e88a7 Mon Sep 17 00:00:00 2001 From: Jeff Vander Stoep Date: Thu, 23 Jan 2020 09:51:14 +0100 Subject: [PATCH] Revert "ANDROID: security,perf: Allow further restriction of perf_event_open" Unfork Android. This reverts commit 5dbd8df7b35643210226329bd7e60658c07a036f. 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/ IGNORE_MERGE_CONFLICT_CHECK==kernel.rst documentation uses "====". Bug: 120445712 Bug: 137092007 Signed-off-by: Jeff Vander Stoep Change-Id: Iba493424174b30baff460caaa25a54a472c87bd4 --- Documentation/admin-guide/sysctl/kernel.rst | 5 +---- arch/arm64/configs/gki_defconfig | 1 - arch/x86/configs/gki_defconfig | 1 - include/linux/perf_event.h | 5 ----- kernel/events/core.c | 8 -------- security/Kconfig | 9 --------- 6 files changed, 1 insertion(+), 28 deletions(-) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 172fac5c58b1..032c7cd3cede 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -720,8 +720,7 @@ 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 @@ -735,8 +734,6 @@ CONFIG_SECURITY_PERF_EVENTS_RESTRICT is set, or 2 otherwise. >=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 === ================================================================== diff --git a/arch/arm64/configs/gki_defconfig b/arch/arm64/configs/gki_defconfig index 8c3d74724537..2dfca5fadae2 100644 --- a/arch/arm64/configs/gki_defconfig +++ b/arch/arm64/configs/gki_defconfig @@ -472,7 +472,6 @@ 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 diff --git a/arch/x86/configs/gki_defconfig b/arch/x86/configs/gki_defconfig index 3a6beb7940aa..1cb7ecc48430 100644 --- a/arch/x86/configs/gki_defconfig +++ b/arch/x86/configs/gki_defconfig @@ -405,7 +405,6 @@ 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 diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 5af7ae27b252..4f77b22d47be 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1253,11 +1253,6 @@ 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; diff --git a/kernel/events/core.c b/kernel/events/core.c index ceabadc1f976..e302077b9ce1 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -398,13 +398,8 @@ 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 */ @@ -10927,9 +10922,6 @@ 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) diff --git a/security/Kconfig b/security/Kconfig index c66f43a36dbe..2a1a2d396228 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -19,15 +19,6 @@ 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