[patch 06/16] file caps: always start with clear bprm->caps_*

[Greg KH <gregkh@suse.de>]

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2.6.25-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Serge Hallyn <serue@us.ibm.com>

commit 3318a386e4ca68c76e0294363d29bdc46fcad670 upstream

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 <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 security/commoncap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -244,10 +244,10 @@ static int get_file_caps(struct linux_bi
 	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;

--