Commit-ID: 93193230f7b8bd484d1749f4044d1214d521c804 Gitweb: http://git.kernel.org/tip/93193230f7b8bd484d1749f4044d1214d521c804 Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Mon, 9 May 2016 15:48:51 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 10 May 2016 09:58:51 +0200 perf/core: Change the default paranoia level to 2 Allowing unprivileged kernel profiling lets any user dump follow kernel control flow and dump kernel registers. This most likely allows trivial kASLR bypassing, and it may allow other mischief as well. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Cc: Jann Horn <jann@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- Documentation/sysctl/kernel.txt | 2 +- kernel/events/core.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 57653a4..fcddfd5 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -645,7 +645,7 @@ allowed to execute. perf_event_paranoid: Controls use of the performance events system by unprivileged -users (without CAP_SYS_ADMIN). The default value is 1. +users (without CAP_SYS_ADMIN). The default value is 2. -1: Allow use of (almost) all events by all users >=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK diff --git a/kernel/events/core.c b/kernel/events/core.c index 4e2ebf6..c0ded24 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -351,7 +351,7 @@ static struct srcu_struct pmus_srcu; * 1 - disallow cpu events for unpriv * 2 - disallow kernel profiling for unpriv */ -int sysctl_perf_event_paranoid __read_mostly = 1; +int sysctl_perf_event_paranoid __read_mostly = 2; /* Minimum for 512 kiB + 1 user control page */ int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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