From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: [PATCH 3/6] IMA: use unsigned int instead of long for counters Date: Tue, 19 Oct 2010 18:58:26 -0400 Message-ID: <20101019225826.12396.52631.stgit@paris.rdu.redhat.com> References: <20101019225813.12396.2564.stgit@paris.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: hch@infradead.org, zohar@us.ibm.com, warthog9@kernel.org, david@fromorbit.com, jmorris@namei.org, kyle@mcmartin.ca, hpa@zytor.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, mingo@elte.hu, eparis@redhat.com, viro@zeniv.linux.org.uk To: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <20101019225813.12396.2564.stgit@paris.rdu.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Currently IMA uses 2 longs in struct inode. To save space (and as it seems impossible to overflow 32 bits) we switch these to unsigned int. The switch to unsigned does require slightly different checks for underflow, but it isn't complex. Signed-off-by: Eric Paris --- include/linux/fs.h | 4 ++-- security/integrity/ima/ima_iint.c | 4 ++-- security/integrity/ima/ima_main.c | 15 ++++++++++----- 3 files changed, 14 insertions(+), 9 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 593bb4d..8f46e5b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -778,8 +778,8 @@ struct inode { #endif #ifdef CONFIG_IMA /* all protected by i_mutex */ - long i_readers; /* struct files open RO */ - long i_writers; /* struct files open WR */ + unsigned int i_readers; /* struct files open RO */ + unsigned int i_writers; /* struct files open WR */ #endif #ifdef CONFIG_FS_POSIX_ACL struct posix_acl *i_acl; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index 2dc32d6..d327840 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -76,9 +76,9 @@ out: void ima_check_counters(struct inode *inode) { if (inode->i_readers) - printk(KERN_INFO "%s: readcount: %ld\n", __func__, inode->i_readers); + printk(KERN_INFO "%s: readcount: %u\n", __func__, inode->i_readers); if (inode->i_writers) - printk(KERN_INFO "%s: writers: %ld\n", __func__, inode->i_writers); + printk(KERN_INFO "%s: writers: %u\n", __func__, inode->i_writers); inode->i_readers = 0; inode->i_writers = 0; diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 92235a0..68ecb43 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -181,12 +181,19 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode, struct file *file) { mode_t mode = file->f_mode; + bool dump = false; + BUG_ON(!mutex_is_locked(&iint->mutex)); BUG_ON(!mutex_is_locked(&inode->i_mutex)); - if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) + if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) { + if (unlikely(inode->i_readers == 0)) + dump = true; inode->i_readers--; + } if (mode & FMODE_WRITE) { + if (unlikely(inode->i_writers == 0)) + dump = true; inode->i_writers--; if (inode->i_writers == 0) { if (iint->version != inode->i_version) @@ -194,10 +201,8 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode, } } - if (((inode->i_readers < 0) || - (inode->i_writers < 0)) && - !ima_limit_imbalance(file)) { - printk(KERN_INFO "%s: open/free imbalance (r:%ld w:%ld)\n", + if (dump && !ima_limit_imbalance(file)) { + printk(KERN_INFO "%s: open/free imbalance (r:%u w:%u)\n", __func__, inode->i_readers, inode->i_writers); dump_stack(); }