From 219f0817038cabc722968e914490adf6b686499e Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Mon, 18 Apr 2005 10:47:35 -0700 Subject: [PATCH] [PATCH] SELinux: fix deadlock on dcache lock This fixes a deadlock on the dcache lock detected during testing at IBM by moving the logging of the current executable information from the SELinux avc_audit function to audit_log_exit (via an audit_log_task_info helper) for processing upon syscall exit. For consistency, the patch also removes the logging of other task-related information from avc_audit, deferring handling to audit_log_exit instead. This allows simplification of the avc_audit code, allows the exe information to be obtained more reliably, always includes the comm information (useful for scripts), and avoids including bogus task information for checks performed from irq or softirq. Signed-off-by: Stephen Smalley Signed-off-by: James Morris Signed-off-by: Linus Torvalds --- kernel/auditsc.c | 28 ++++++++++++++++++++++++++++ security/selinux/avc.c | 34 ---------------------------------- 2 files changed, 28 insertions(+), 34 deletions(-) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 8c454852d6a..6f1931381bc 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -610,6 +610,33 @@ static inline void audit_free_context(struct audit_context *context) printk(KERN_ERR "audit: freed %d contexts\n", count); } +static void audit_log_task_info(struct audit_buffer *ab) +{ + char name[sizeof(current->comm)]; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + + get_task_comm(name, current); + audit_log_format(ab, " comm=%s", name); + + if (!mm) + return; + + down_read(&mm->mmap_sem); + vma = mm->mmap; + while (vma) { + if ((vma->vm_flags & VM_EXECUTABLE) && + vma->vm_file) { + audit_log_d_path(ab, "exe=", + vma->vm_file->f_dentry, + vma->vm_file->f_vfsmnt); + break; + } + vma = vma->vm_next; + } + up_read(&mm->mmap_sem); +} + static void audit_log_exit(struct audit_context *context) { int i; @@ -639,6 +666,7 @@ static void audit_log_exit(struct audit_context *context) context->gid, context->euid, context->suid, context->fsuid, context->egid, context->sgid, context->fsgid); + audit_log_task_info(ab); audit_log_end(ab); while (context->aux) { struct audit_aux_data *aux; diff --git a/security/selinux/avc.c b/security/selinux/avc.c index fe6285e5c68..85a6f66a873 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -532,7 +532,6 @@ void avc_audit(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct av_decision *avd, int result, struct avc_audit_data *a) { - struct task_struct *tsk = current; struct inode *inode = NULL; u32 denied, audited; struct audit_buffer *ab; @@ -556,39 +555,6 @@ void avc_audit(u32 ssid, u32 tsid, audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted"); avc_dump_av(ab, tclass,audited); audit_log_format(ab, " for "); - if (a && a->tsk) - tsk = a->tsk; - if (tsk && tsk->pid) { - struct mm_struct *mm; - struct vm_area_struct *vma; - audit_log_format(ab, " pid=%d", tsk->pid); - if (tsk == current) - mm = current->mm; - else - mm = get_task_mm(tsk); - if (mm) { - if (down_read_trylock(&mm->mmap_sem)) { - vma = mm->mmap; - while (vma) { - if ((vma->vm_flags & VM_EXECUTABLE) && - vma->vm_file) { - audit_log_d_path(ab, "exe=", - vma->vm_file->f_dentry, - vma->vm_file->f_vfsmnt); - break; - } - vma = vma->vm_next; - } - up_read(&mm->mmap_sem); - } else { - audit_log_format(ab, " comm=%s", tsk->comm); - } - if (tsk != current) - mmput(mm); - } else { - audit_log_format(ab, " comm=%s", tsk->comm); - } - } if (a) { switch (a->type) { case AVC_AUDIT_DATA_IPC: -- 2.20.1