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author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2018-12-12 14:08:45 +0100 |
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committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2018-12-12 14:08:45 +0100 |
commit | cfbbc7703fff59c67761c93a8b1de29a79f9841c (patch) | |
tree | 58b4b37bed385b27fc5956435b2451c760f26f5f /fs/proc/base.c | |
parent | 5f3fecbc0715a70437501e1d85e74726c4f561be (diff) | |
parent | 1aa861ff238ecd17a3095b0dbd2d20bdf7bfaf14 (diff) |
Merge tag 'v4.9.144' into 4.9-2.3.x-imx
This is the 4.9.144 stable 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 591bf2b1ab66..79702d405ba7 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -454,6 +454,20 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns, int err; int i; + /* + * 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(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL); if (!entries) return -ENOMEM; |