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| author | Wolfram Sang <wsa@the-dreams.de> | 2018-10-11 23:07:30 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2018-10-11 23:07:30 +0200 |
| commit | 90fb814b6c025da45f71db1703cffe3fe87f575c (patch) | |
| tree | 5fd739d407654df6f9d6e82900a45e027dd8b9f0 /fs/proc/base.c | |
| parent | b30f2f65568f840e5ca522d98ba2ad73b8f59cde (diff) | |
| parent | 0238df646e6224016a45505d2c111a24669ebe21 (diff) | |
Merge tag 'v4.19-rc7' into i2c/for-4.20
This is the 4.19-rc7 release
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) |