diff options
| author | Ingo Molnar <mingo@kernel.org> | 2018-10-09 08:50:10 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-10-09 08:50:10 +0200 |
| commit | fc8eaa85681fa72dc6a4e46f01c92e4fba83d0ab (patch) | |
| tree | b044fab426f2167ceeb37ed6fe58f7f11b10cebd /fs/proc/base.c | |
| parent | 2cc81c6992248ea37d0241bc325977bab310bc3b (diff) | |
| parent | 49e00eee00612b1357596fed8a88b621a7648c14 (diff) | |
Merge branch 'x86/urgent' into x86/cache, to pick up dependent fix
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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) |