6.1-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
[ Upstream commit ba677dbe77af5ffe6204e0f3f547f3ba059c6302 ]
Jann reports that uprobes can be used destructively when used in the middle of an instruction. The kernel only verifies there is a valid instruction at the requested offset, but due to variable instruction length cannot determine if this is an instruction as seen by the intended execution stream.
Additionally, Mark Rutland notes that on architectures that mix data in the text segment (like arm64), a similar things can be done if the data word is 'mistaken' for an instruction.
As such, require CAP_SYS_ADMIN for uprobes.
Fixes: c9e0924e5c2b ("perf/core: open access to probes for CAP_PERFMON privileged process") Reported-by: Jann Horn jannh@google.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lkml.kernel.org/r/CAG48ez1n4520sq0XrWYDHKiKxE_+WCfAK+qt9qkY4ZiBGmL-5... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 2761db0365ddc..f815b808db20a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10207,7 +10207,7 @@ static int perf_uprobe_event_init(struct perf_event *event) if (event->attr.type != perf_uprobe.type) return -ENOENT;
- if (!perfmon_capable()) + if (!capable(CAP_SYS_ADMIN)) return -EACCES;
/*