security: filesystem capabilities: fix CAP_SETPCAP handling
The filesystem capability support meaning for CAP_SETPCAP is less powerful
than the non-filesystem capability support. As such, when filesystem
capabilities are configured, we should not permit CAP_SETPCAP to 'enhance'
the current process through strace manipulation of a child process.
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/security/commoncap.c b/security/commoncap.c
index 5edabc7..33d3433 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -103,10 +103,16 @@
return (cap_capable(current, CAP_SETPCAP) != 0);
}
+static inline int cap_limit_ptraced_target(void) { return 1; }
+
#else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
static inline int cap_block_setpcap(struct task_struct *t) { return 0; }
static inline int cap_inh_is_capped(void) { return 1; }
+static inline int cap_limit_ptraced_target(void)
+{
+ return !capable(CAP_SETPCAP);
+}
#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
@@ -342,9 +348,10 @@
bprm->e_uid = current->uid;
bprm->e_gid = current->gid;
}
- if (!capable (CAP_SETPCAP)) {
- new_permitted = cap_intersect (new_permitted,
- current->cap_permitted);
+ if (cap_limit_ptraced_target()) {
+ new_permitted =
+ cap_intersect(new_permitted,
+ current->cap_permitted);
}
}
}