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From: Mateusz Guzik <>
To: Alexander Viro <>,
	Serge Hallyn <>
Cc: Paul Moore <>, Eric Paris <>,,,
Subject: [PATCH 0/2] avoid prepare_creds in faccessat when possible
Date: Mon,  9 Mar 2015 21:35:45 +0100	[thread overview]
Message-ID: <> (raw)

Sometimes faccessat needs to modify current thread's credentials, but
calls prepare_creds unconditionally.

However, typically resulting credentials are identical to original ones
and in that case newcredentials are unnecessary. We can detect this before
allocating anything.

This patch series adds a helper which allows comparing capability sets and
modifies faccessat to use it.

Mateusz Guzik (2):
  CAPABILITIES: add cap_isequal helper
  fs: avoid unnecessary prepare_creds in faccessat

 fs/open.c                  | 53 ++++++++++++++++++++++++++++++----------------
 include/linux/capability.h | 10 +++++++++
 2 files changed, 45 insertions(+), 18 deletions(-)


             reply	other threads:[~2015-03-09 20:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-09 20:35 Mateusz Guzik [this message]
2015-03-09 20:35 ` [PATCH 1/2] CAPABILITIES: add cap_isequal helper Mateusz Guzik
2015-03-13 14:02   ` Paul Moore
2015-03-13 16:13     ` Mateusz Guzik
2015-03-09 20:35 ` [PATCH 2/2] fs: avoid unnecessary prepare_creds in faccessat Mateusz Guzik
2015-03-13 12:08 ` [PATCH 0/2] avoid prepare_creds in faccessat when possible Mateusz Guzik

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