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| author | Arnaldo Carvalho de Melo <[email protected]> | 2018-10-18 14:13:01 +0000 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <[email protected]> | 2018-10-18 14:13:01 +0000 |
| commit | ce6c9da1113ad681bff27a3e376d2017f7f8a59c (patch) | |
| tree | 922ee99522f8e47e4fa5c735d4ea378dfdb79085 /fs/proc/base.c | |
| parent | perf/x86/intel: Export mem events only if there's PEBS support (diff) | |
| parent | Merge tag 'perf-urgent-for-mingo-4.19-20181017' of git://git.kernel.org/pub/s... (diff) | |
| download | kernel-ce6c9da1113ad681bff27a3e376d2017f7f8a59c.tar.gz kernel-ce6c9da1113ad681bff27a3e376d2017f7f8a59c.zip | |
Merge remote-tracking branch 'tip/perf/urgent' into perf/core
To pick up fixes.
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Diffstat (limited to 'fs/proc/base.c')
| -rw-r--r-- | fs/proc/base.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index ccf86f16d9f0..7e9f07bf260d 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -407,6 +407,20 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns, unsigned long *entries; int err; + /* + * The ability to racily run the kernel stack unwinder on a running task + * and then observe the unwinder output is scary; while it is useful for + * debugging kernel issues, it can also allow an attacker to leak kernel + * stack contents. + * Doing this in a manner that is at least safe from races would require + * some work to ensure that the remote task can not be scheduled; and + * even then, this would still expose the unwinder as local attack + * surface. + * Therefore, this interface is restricted to root. + */ + if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) + return -EACCES; + entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries), GFP_KERNEL); if (!entries) |