The patch titled
Subject: proc: don't show nonexistent capabilities
has been added to the -mm tree. Its filename is
proc-dont-show-nonexistent-capabilities.patch
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------------------------------------------------------
From: Andrew Vagin <avagin@xxxxxxxxxx>
Subject: proc: don't show nonexistent capabilities
Without this patch it is really hard to interpret a bounding set, if
CAP_LAST_CAP is unknown for a current kernel.
Non-existant capabilities can not be deleted from a bounding set with help
of prctl.
E.g.: Here are two examples without/with this patch.
CapBnd: ffffffe0fdecffff
CapBnd: 00000000fdecffff
I suggest to hide non-existent capabilities. Here is two reasons.
* It's logically and easier for using.
* It helps to checkpoint-restore capabilities of tasks, because tasks
can be restored on another kernel, where CAP_LAST_CAP is bigger.
Signed-off-by: Andrew Vagin <avagin@xxxxxxxxxx>
Cc: Andrew G. Morgan <morgan@xxxxxxxxxx>
Reviewed-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/array.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff -puN fs/proc/array.c~proc-dont-show-nonexistent-capabilities fs/proc/array.c
--- a/fs/proc/array.c~proc-dont-show-nonexistent-capabilities
+++ a/fs/proc/array.c
@@ -308,6 +308,10 @@ static void render_cap_t(struct seq_file
seq_putc(m, '\n');
}
+/* Remove non-existent capabilities */
+#define NORM_CAPS(v) (v.cap[CAP_TO_INDEX(CAP_LAST_CAP)] &= \
+ CAP_TO_MASK(CAP_LAST_CAP + 1) - 1)
+
static inline void task_cap(struct seq_file *m, struct task_struct *p)
{
const struct cred *cred;
@@ -321,6 +325,11 @@ static inline void task_cap(struct seq_f
cap_bset = cred->cap_bset;
rcu_read_unlock();
+ NORM_CAPS(cap_inheritable);
+ NORM_CAPS(cap_permitted);
+ NORM_CAPS(cap_effective);
+ NORM_CAPS(cap_bset);
+
render_cap_t(m, "CapInh:\t", &cap_inheritable);
render_cap_t(m, "CapPrm:\t", &cap_permitted);
render_cap_t(m, "CapEff:\t", &cap_effective);
_
Patches currently in -mm which might be from avagin@xxxxxxxxxx are
origin.patch
pidns-remove-recursion-from-free_pid_ns-v3.patch
proc-dont-show-nonexistent-capabilities.patch
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