From: Mimi Zohar <zohar@linux.vnet.ibm.com> To: Matthew Wilcox <willy@infradead.org> Cc: linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, Christoph Hellwig <hch@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Jan Kara <jack@suse.cz>, "Theodore Ts'o" <tytso@mit.edu> Subject: Re: [RFC PATCH 1/3] fs: define new read_iter rwf flag Date: Thu, 28 Sep 2017 10:33:23 -0400 [thread overview] Message-ID: <1506609203.5022.1.camel@linux.vnet.ibm.com> (raw) In-Reply-To: <20170928135416.GA30859@bombadil.infradead.org> On Thu, 2017-09-28 at 06:54 -0700, Matthew Wilcox wrote: > On Thu, Sep 28, 2017 at 08:39:31AM -0400, Mimi Zohar wrote: > > Writing extended attributes requires exclusively taking the i_rwsem > > lock. To synchronize the file hash calculation and writing the file > > hash as security.ima xattr, IMA-appraisal takes the i_rwsem lock > > exclusively before calculating the file hash. (Once the file hash > > is calculated, the result is cached. Taking the lock exclusively > > prevents calculating the file hash multiple times.) > > > > Some filesystems have recently replaced their filesystem dependent > > lock with the global i_rwsem to read a file. As a result, when IMA > > attempts to calculate the file hash, reading the file attempts to > > take the i_rwsem again. > > > > To resolve this problem, this patch defines a new read_iter flag > > named "rwf" to indicate that the i_rwsem has already been taken > > exclusively. Subsequent patches will set or test the "rwf" flag. > > I don't like adding a bool parameter everywhere. Me either! > Why not add a flag > to the kiocb ki_flags? > > #define IOCB_RWSEM_HELD (1 << 8) Thank you for the suggestion. > -- > To unsubscribe from this list: send the line "unsubscribe linux-security-module" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
WARNING: multiple messages have this Message-ID (diff)
From: zohar@linux.vnet.ibm.com (Mimi Zohar) To: linux-security-module@vger.kernel.org Subject: [RFC PATCH 1/3] fs: define new read_iter rwf flag Date: Thu, 28 Sep 2017 10:33:23 -0400 [thread overview] Message-ID: <1506609203.5022.1.camel@linux.vnet.ibm.com> (raw) In-Reply-To: <20170928135416.GA30859@bombadil.infradead.org> On Thu, 2017-09-28 at 06:54 -0700, Matthew Wilcox wrote: > On Thu, Sep 28, 2017 at 08:39:31AM -0400, Mimi Zohar wrote: > > Writing extended attributes requires exclusively taking the i_rwsem > > lock. To synchronize the file hash calculation and writing the file > > hash as security.ima xattr, IMA-appraisal takes the i_rwsem lock > > exclusively before calculating the file hash. (Once the file hash > > is calculated, the result is cached. Taking the lock exclusively > > prevents calculating the file hash multiple times.) > > > > Some filesystems have recently replaced their filesystem dependent > > lock with the global i_rwsem to read a file. As a result, when IMA > > attempts to calculate the file hash, reading the file attempts to > > take the i_rwsem again. > > > > To resolve this problem, this patch defines a new read_iter flag > > named "rwf" to indicate that the i_rwsem has already been taken > > exclusively. Subsequent patches will set or test the "rwf" flag. > > I don't like adding a bool parameter everywhere. Me either! > Why not add a flag > to the kiocb ki_flags? > > #define IOCB_RWSEM_HELD (1 << 8) Thank you for the suggestion. > -- > To unsubscribe from this list: send the line "unsubscribe linux-security-module" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-09-28 14:33 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-09-28 12:39 [RFC PATCH 0/3] define new read_iter file operation rwf flag Mimi Zohar 2017-09-28 12:39 ` Mimi Zohar 2017-09-28 12:39 ` [RFC PATCH 1/3] fs: define new read_iter " Mimi Zohar 2017-09-28 12:39 ` Mimi Zohar 2017-09-28 13:54 ` Matthew Wilcox 2017-09-28 13:54 ` Matthew Wilcox 2017-09-28 14:33 ` Mimi Zohar [this message] 2017-09-28 14:33 ` Mimi Zohar 2017-09-28 15:51 ` Linus Torvalds 2017-09-28 15:51 ` Linus Torvalds 2017-09-28 12:39 ` [RFC PATCH 2/3] integrity: use call_read_iter to calculate the file hash Mimi Zohar 2017-09-28 12:39 ` Mimi Zohar 2017-09-28 12:39 ` [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar 2017-09-28 12:39 ` Mimi Zohar 2017-09-28 22:02 ` Dave Chinner 2017-09-28 22:02 ` Dave Chinner 2017-09-28 23:39 ` Linus Torvalds 2017-09-28 23:39 ` Linus Torvalds 2017-09-29 0:12 ` Mimi Zohar 2017-09-29 0:12 ` Mimi Zohar 2017-09-29 0:12 ` Mimi Zohar 2017-09-29 0:33 ` Linus Torvalds 2017-09-29 0:33 ` Linus Torvalds 2017-09-29 1:53 ` Mimi Zohar 2017-09-29 1:53 ` Mimi Zohar 2017-09-29 1:53 ` Mimi Zohar 2017-09-29 3:26 ` Linus Torvalds 2017-09-29 3:26 ` Linus Torvalds 2017-10-01 1:33 ` Eric W. Biederman 2017-10-01 1:33 ` Eric W. Biederman [not found] ` <CA+55aFx726wT4VprN-sHm6s8Q_PV_VjhTBC4goEbMcerYU1Tig@mail.gmail.com> 2017-10-01 12:08 ` Mimi Zohar 2017-10-01 12:08 ` Mimi Zohar 2017-10-01 12:08 ` Mimi Zohar 2017-10-01 18:41 ` Linus Torvalds 2017-10-01 18:41 ` Linus Torvalds 2017-10-01 22:34 ` Dave Chinner 2017-10-01 22:34 ` Dave Chinner 2017-10-01 23:15 ` Linus Torvalds 2017-10-01 23:15 ` Linus Torvalds 2017-10-02 3:54 ` Dave Chinner 2017-10-02 3:54 ` Dave Chinner 2017-10-01 23:42 ` Mimi Zohar 2017-10-01 23:42 ` Mimi Zohar 2017-10-01 23:42 ` Mimi Zohar 2017-10-02 3:25 ` Eric W. Biederman 2017-10-02 3:25 ` Eric W. Biederman 2017-10-02 3:25 ` Eric W. Biederman 2017-10-02 12:25 ` Mimi Zohar 2017-10-02 12:25 ` Mimi Zohar 2017-10-02 12:25 ` Mimi Zohar 2017-10-02 4:35 ` Dave Chinner 2017-10-02 4:35 ` Dave Chinner 2017-10-02 4:35 ` Dave Chinner 2017-10-02 4:35 ` Dave Chinner 2017-10-02 12:09 ` Mimi Zohar 2017-10-02 12:09 ` Mimi Zohar 2017-10-02 12:09 ` Mimi Zohar 2017-10-02 12:43 ` Jeff Layton 2017-10-02 12:43 ` Jeff Layton 2017-10-01 22:06 ` Eric W. Biederman 2017-10-01 22:06 ` Eric W. Biederman 2017-10-01 22:20 ` Linus Torvalds 2017-10-01 22:20 ` Linus Torvalds 2017-10-01 23:54 ` Mimi Zohar 2017-10-01 23:54 ` Mimi Zohar 2017-10-01 23:54 ` Mimi Zohar
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