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@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html >
