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authorAndrew Vagin <avagin@openvz.org>2012-12-17 16:03:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-17 17:15:22 -0800
commit7b9a7ec565505699f503b4fcf61500dceb36e744 (patch)
tree1a0c3f91d613e4e07e858ba93e28344056356c7c /fs/proc
parent992fb6e170639b0849bace8e49bf31bd37c4123c (diff)
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@openvz.org> Cc: Andrew G. Morgan <morgan@kernel.org> Reviewed-by: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Pavel Emelyanov <xemul@parallels.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/array.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c
index d3696708fc1a..377a37366dde 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -308,6 +308,10 @@ static void render_cap_t(struct seq_file *m, const char *header,
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_file *m, struct task_struct *p)
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);