Re: 2.6.12-rc4-mm2 - sleeping function called from invalid context at mm/slab.c:2502

On Fri, 2005-05-20 at 17:55 +0100, David Woodhouse wrote: This patch changes the SELinux AVC to defer logging of paths to the audit framework upon syscall exit, by saving a reference to the (dentry,vfsmount) pair in an auxiliary audit item on the current audit context for processing by audit_log_exit. Signed-off-by: Stephen Smalley <sds(a)tycho.nsa.gov&gt; --- include/linux/audit.h | 3 +++ kernel/auditsc.c | 39 +++++++++++++++++++++++++++++++++++++++ security/selinux/avc.c | 17 ++++++++--------- 3 files changed, 50 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 13:17:21.000000000 -0400 @@ -75,6 +75,7 @@ #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ +#define AUDIT_AVC_PATH 1402 /* dentry, vfsmount pair from avc */ #define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */ @@ -238,6 +239,7 @@ 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 +255,7 @@ 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 13:21:40.000000000 -0400 @@ -34,6 +34,7 @@ #include <asm/types.h> #include <linux/mm.h> #include <linux/module.h> +#include <linux/mount.h> #include <linux/socket.h> #include <linux/audit.h> #include <linux/personality.h> @@ -124,6 +125,11 @@ struct audit_aux_data_sockaddr { char a[0]; }; +struct audit_aux_data_path { + 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_PATH) { + struct audit_aux_data_path *axi = (void *)aux; + dput(axi->dentry); + mntput(axi->mnt); + } context->aux = aux->next; kfree(aux); } @@ -728,6 +739,13 @@ static void audit_log_exit(struct audit_ } /* case AUDIT_SOCKADDR */ break; + case AUDIT_AVC_PATH: { + struct audit_aux_data_path *axi = (void *)aux; + audit_log_d_path(ab, "path=", axi->dentry, axi->mnt); + dput(axi->dentry); + mntput(axi->mnt); + } /* case AUDIT_AVC_PATH */ + break; } audit_log_end(ab); @@ -1128,6 +1146,27 @@ int audit_sockaddr(int len, void *a) return 0; } +int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt) +{ + struct audit_aux_data_path *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_PATH; + 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