Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=8ec2328f1138a58eaea55ec6150985a1623b01c5
Commit: 8ec2328f1138a58eaea55ec6150985a1623b01c5
Parent: d0eec99ce50baa5cc2ac02363cdb2a771ed4e1e2
Author: Serge E. Hallyn <[EMAIL PROTECTED]>
AuthorDate: Wed Nov 28 16:21:47 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Nov 29 09:24:53 2007 -0800
file capabilities: don't prevent signaling setuid root programs
An unprivileged process must be able to kill a setuid root program started
by the same user. This is legacy behavior needed for instance for xinit to
kill X when the window manager exits.
When an unprivileged user runs a setuid root program in !SECURE_NOROOT
mode, fP, fI, and fE are set full on, so pP' and pE' are full on. Then
cap_task_kill() prevents the user from signaling the setuid root task.
This is a change in behavior compared to when
!CONFIG_SECURITY_FILE_CAPABILITIES.
This patch introduces a special check into cap_task_kill() just to check
whether a non-root user is signaling a setuid root program started by the
same user. If so, then signal is allowed.
Signed-off-by: Serge E. Hallyn <[EMAIL PROTECTED]>
Cc: Andrew Morgan <[EMAIL PROTECTED]>
Cc: Stephen Smalley <[EMAIL PROTECTED]>
Cc: Chris Wright <[EMAIL PROTECTED]>
Cc: James Morris <[EMAIL PROTECTED]>
Cc: Casey Schaufler <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
security/commoncap.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index 302e8d0..5bc1895 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -526,6 +526,15 @@ int cap_task_kill(struct task_struct *p, struct siginfo
*info,
if (info != SEND_SIG_NOINFO && (is_si_special(info) ||
SI_FROMKERNEL(info)))
return 0;
+ /*
+ * Running a setuid root program raises your capabilities.
+ * Killing your own setuid root processes was previously
+ * allowed.
+ * We must preserve legacy signal behavior in this case.
+ */
+ if (p->euid == 0 && p->uid == current->uid)
+ return 0;
+
/* sigcont is permitted within same session */
if (sig == SIGCONT && (task_session_nr(current) == task_session_nr(p)))
return 0;
-
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