2008-10-31 14:08:50

by Serge E. Hallyn

[permalink] [raw]
Subject: [PATCH 1/1] file caps: always start with clear bprm->caps_*

(Sorry, resending as I seemed to have dropped lkml from the headers on
yesterday's post)

>From c7b9b5534182566b4526e6a5bd4641bd0ae99676 Mon Sep 17 00:00:00 2001
From: Serge Hallyn <[email protected]>
Date: Thu, 30 Oct 2008 11:52:23 -0500
Subject: [PATCH 1/1] file caps: always start with clear bprm->caps_*

While Linux doesn't honor setuid on scripts. However, it mistakenly
behaves differently for file capabilities.

This patch fixes that behavior by making sure that get_file_caps()
begins with empty bprm->caps_*. That way when a script is loaded,
its bprm->caps_* may be filled when binfmt_misc calls prepare_binprm(),
but they will be cleared again when binfmt_elf calls prepare_binprm()
next to read the interpreter's file capabilities.

Signed-off-by: Serge Hallyn <[email protected]>
Acked-by: David Howells <[email protected]>
Acked-by: Andrew G. Morgan <[email protected]>
---
security/commoncap.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index 399bfdb..3976613 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -279,10 +279,10 @@ static int get_file_caps(struct linux_binprm *bprm)
struct vfs_cap_data vcaps;
struct inode *inode;

- if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) {
- bprm_clear_caps(bprm);
+ bprm_clear_caps(bprm);
+
+ if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
return 0;
- }

dentry = dget(bprm->file->f_dentry);
inode = dentry->d_inode;
--
1.5.6.3