Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261497AbVETQt6 (ORCPT ); Fri, 20 May 2005 12:49:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261498AbVETQt6 (ORCPT ); Fri, 20 May 2005 12:49:58 -0400 Received: from mummy.ncsc.mil ([144.51.88.129]:22489 "EHLO jazzhorn.ncsc.mil") by vger.kernel.org with ESMTP id S261497AbVETQts (ORCPT ); Fri, 20 May 2005 12:49:48 -0400 Subject: Re: 2.6.12-rc4-mm2 - sleeping function called from invalid context at mm/slab.c:2502 From: Stephen Smalley To: Linux Audit Discussion Cc: linux-kernel@vger.kernel.org In-Reply-To: <1116603414.29037.36.camel@localhost.localdomain> References: <200505171624.j4HGOQwo017312@turing-police.cc.vt.edu> <1116502449.23972.207.camel@hades.cambridge.redhat.com> <200505191845.j4JIjVtq006262@turing-police.cc.vt.edu> <200505201430.j4KEUFD0012985@turing-police.cc.vt.edu> <1116601195.29037.18.camel@localhost.localdomain> <1116601757.12489.130.camel@moss-spartans.epoch.ncsc.mil> <1116603414.29037.36.camel@localhost.localdomain> Content-Type: text/plain Organization: National Security Agency Date: Fri, 20 May 2005 12:40:23 -0400 Message-Id: <1116607223.12489.155.camel@moss-spartans.epoch.ncsc.mil> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-16) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5266 Lines: 161 On Fri, 2005-05-20 at 16:36 +0100, David Woodhouse wrote: > On Fri, 2005-05-20 at 11:09 -0400, Stephen Smalley wrote: > > The lock is being held by the af_unix code (unix_state_wlock), not > > avc_audit; the AVC is called under all kinds of circumstances (softirq, > > hard irq, caller holding locks on relevant objects) for permission > > checking and must never sleep. > > > > One option might be to defer some of the AVC auditing to the audit > > framework (e.g. save the vfsmount and dentry on the current audit > > context and let audit_log_exit perform the audit_log_d_path). > > Yeah, maybe. Assuming you pin them, it's easy enough to hang something > off the audit context's aux list which refers to them. I'm really not > that fond of the idea of allocating a whole PATH_MAX with GFP_ATOMIC. Untested patch below, relative to 2.6.12-rc4-mm2 plus your socketcall patch to avoid the obvious conflict there. Is this what you had in mind? include/linux/audit.h | 2 ++ kernel/auditsc.c | 38 ++++++++++++++++++++++++++++++++++++++ security/selinux/avc.c | 17 ++++++++--------- 3 files changed, 48 insertions(+), 9 deletions(-) --- linux-2.6.12-rc4-mm2/include/linux/audit.h.orig 2005-05-20 12:37:41.000000000 -0400 +++ linux-2.6.12-rc4-mm2/include/linux/audit.h 2005-05-20 12:38:15.000000000 -0400 @@ -238,6 +238,7 @@ extern uid_t audit_get_loginuid(struct a extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode); extern int audit_socketcall(int nargs, unsigned long *args); extern int audit_sockaddr(int len, void *addr); +extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt); extern void audit_signal_info(int sig, struct task_struct *t); #else #define audit_alloc(t) ({ 0; }) @@ -253,6 +254,7 @@ extern void audit_signal_info(int sig, s #define audit_ipc_perms(q,u,g,m) ({ 0; }) #define audit_socketcall(n,a) ({ 0; }) #define audit_sockaddr(len, addr) ({ 0; }) +#define audit_avc_path(dentry, mnt) ({ 0; }) #define audit_signal_info(s,t) do { ; } while (0) #endif --- linux-2.6.12-rc4-mm2/kernel/auditsc.c.orig 2005-05-20 12:37:19.000000000 -0400 +++ linux-2.6.12-rc4-mm2/kernel/auditsc.c 2005-05-20 12:43:05.000000000 -0400 @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -124,6 +125,11 @@ struct audit_aux_data_sockaddr { char a[0]; }; +struct audit_aux_data_avc { + struct audit_aux_data d; + struct dentry *dentry; + struct vfsmount *mnt; +}; /* The per-task audit context. */ struct audit_context { @@ -553,6 +559,11 @@ static inline void audit_free_aux(struct struct audit_aux_data *aux; while ((aux = context->aux)) { + if (aux->type == AUDIT_AVC) { + struct audit_aux_data_avc *axi = (void *)aux; + dput(axi->dentry); + mntput(axi->mnt); + } context->aux = aux->next; kfree(aux); } @@ -728,6 +739,12 @@ static void audit_log_exit(struct audit_ } /* case AUDIT_SOCKADDR */ break; + case AUDIT_AVC: { + struct audit_aux_data_avc *axi = (void *)aux; + if (axi->dentry) + audit_log_d_path(ab, "path=", axi->dentry, axi->mnt); + } /* case AUDIT_AVC */ + break; } audit_log_end(ab); @@ -1128,6 +1145,27 @@ int audit_sockaddr(int len, void *a) return 0; } +int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt) +{ + struct audit_aux_data_avc *ax; + struct audit_context *context = current->audit_context; + + if (likely(!context)) + return 0; + + ax = kmalloc(sizeof(*ax), GFP_ATOMIC); + if (!ax) + return -ENOMEM; + + ax->dentry = dget(dentry); + ax->mnt = mntget(mnt); + + ax->d.type = AUDIT_AVC; + ax->d.next = context->aux; + context->aux = (void *)ax; + return 0; +} + void audit_signal_info(int sig, struct task_struct *t) { extern pid_t audit_sig_pid; --- linux-2.6.12-rc4-mm2/security/selinux/avc.c.orig 2005-05-20 12:37:41.000000000 -0400 +++ linux-2.6.12-rc4-mm2/security/selinux/avc.c 2005-05-20 12:39:06.000000000 -0400 @@ -566,13 +566,10 @@ void avc_audit(u32 ssid, u32 tsid, case AVC_AUDIT_DATA_FS: if (a->u.fs.dentry) { struct dentry *dentry = a->u.fs.dentry; - if (a->u.fs.mnt) { - audit_log_d_path(ab, "path=", dentry, - a->u.fs.mnt); - } else { - audit_log_format(ab, " name=%s", - dentry->d_name.name); - } + if (a->u.fs.mnt) + audit_avc_path(dentry, a->u.fs.mnt); + audit_log_format(ab, " name=%s", + dentry->d_name.name); inode = dentry->d_inode; } else if (a->u.fs.inode) { struct dentry *dentry; @@ -623,8 +620,10 @@ void avc_audit(u32 ssid, u32 tsid, case AF_UNIX: u = unix_sk(sk); if (u->dentry) { - audit_log_d_path(ab, "path=", - u->dentry, u->mnt); + audit_avc_path(u->dentry, u->mnt); + audit_log_format(ab, " name=%s", + u->dentry->d_name.name); + break; } if (!u->addr) -- Stephen Smalley National Security Agency - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/