diff options
Diffstat (limited to 'debian/patches/features/all/security-perf-allow-further-restriction-of-perf_event_open.patch')
| -rw-r--r-- | debian/patches/features/all/security-perf-allow-further-restriction-of-perf_event_open.patch | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/debian/patches/features/all/security-perf-allow-further-restriction-of-perf_event_open.patch b/debian/patches/features/all/security-perf-allow-further-restriction-of-perf_event_open.patch new file mode 100644 index 000000000..33db1f765 --- /dev/null +++ b/debian/patches/features/all/security-perf-allow-further-restriction-of-perf_event_open.patch @@ -0,0 +1,80 @@ +From: Ben Hutchings <ben@decadent.org.uk> +Date: Mon, 11 Jan 2016 15:23:55 +0000 +Subject: security,perf: Allow further restriction of perf_event_open +Forwarded: https://lkml.org/lkml/2016/1/11/587 + +When kernel.perf_event_open is set to 3 (or greater), disallow all +access to performance events by users without CAP_SYS_ADMIN. +Add a Kconfig symbol CONFIG_SECURITY_PERF_EVENTS_RESTRICT that +makes this value the default. + +This is based on a similar feature in grsecurity +(CONFIG_GRKERNSEC_PERF_HARDEN). This version doesn't include making +the variable read-only. It also allows enabling further restriction +at run-time regardless of whether the default is changed. + +Signed-off-by: Ben Hutchings <ben@decadent.org.uk> +--- + include/linux/perf_event.h | 5 +++++ + kernel/events/core.c | 8 ++++++++ + security/Kconfig | 9 +++++++++ + 3 files changed, 22 insertions(+) + +--- a/include/linux/perf_event.h ++++ b/include/linux/perf_event.h +@@ -1305,6 +1305,11 @@ int perf_cpu_time_max_percent_handler(st + int perf_event_max_stack_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos); + ++static inline bool perf_paranoid_any(void) ++{ ++ return sysctl_perf_event_paranoid > 2; ++} ++ + /* Access to perf_event_open(2) syscall. */ + #define PERF_SECURITY_OPEN 0 + +--- a/kernel/events/core.c ++++ b/kernel/events/core.c +@@ -408,8 +408,13 @@ 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 */ +@@ -11785,6 +11790,9 @@ SYSCALL_DEFINE5(perf_event_open, + if (err) + return err; + ++ 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) +--- a/security/Kconfig ++++ b/security/Kconfig +@@ -19,6 +19,15 @@ 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 |