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IPC



Here's an untested first attempt at auditing msgctl, semctl and shmctl
IPC_SET calls. It should print the requested uid, gid, mod and qbytes
values. 

We keep a linked list in the audit context, which can be extended to
contain other types of information than the IPC_SET info we add here. I
haven't added any locking -- am I right in thinking that we don't
actually need any?

--- linux-2.6.9/kernel/auditsc.c~	2005-01-31 13:22:07.000000000 +0000
+++ linux-2.6.9/kernel/auditsc.c	2005-02-01 17:33:59.201084736 +0000
@@ -98,6 +98,23 @@ struct audit_names {
 	dev_t		rdev;
 };
 
+struct audit_aux_data {
+	struct audit_aux_data	*next;
+	int			type;
+};
+
+#define AUDIT_AUX_IPCPERM	0
+
+struct audit_aux_data_ipcctl {
+	struct audit_aux_data	d;
+	struct ipc_perm		p;
+	unsigned long		qbytes;
+	uid_t			uid;
+	gid_t			gid;
+	mode_t			mode;
+};
+
+
 /* The per-task audit context. */
 struct audit_context {
 	int		    in_syscall;	/* 1 if task is in a syscall */
@@ -113,6 +130,7 @@ struct audit_context {
 	int		    name_count;
 	struct audit_names  names[AUDIT_NAMES];
 	struct audit_context *previous; /* For nested syscalls */
+	struct audit_aux_data *aux;
 
 				/* Save things to print about task_struct */
 	pid_t		    pid;
@@ -560,6 +578,16 @@ static inline void audit_free_files(stru
 	}
 }
 
+static inline void audit_free_aux(struct audit_context *context)
+{
+	struct audit_aux_data *aux;
+
+	while ((aux = context->aux)) {
+		context->aux = aux;
+		kfree(aux);
+	}
+}
+
 static inline void audit_zero_context(struct audit_context *context,
 				      enum audit_state state)
 {
@@ -628,6 +656,7 @@ static inline void audit_free_context(st
 		}
 		audit_free_names(context);
 		audit_free_files(context);
+		audit_free_aux(context);
 		kfree(context);
 		context  = previous;
 	} while (context);
@@ -666,6 +695,29 @@ static void audit_log_exit(struct audit_
 		  context->euid, context->suid, context->fsuid,
 		  context->egid, context->sgid, context->fsgid);
 	audit_log_end(ab);
+	while (context->aux) {
+		struct audit_aux_data *aux;
+
+		ab = audit_log_start(context);
+		if (!ab)
+			continue; /* audit_panic has been called */
+
+		aux = context->aux;
+		context->aux = aux->next;
+
+		audit_log_format(ab, "auxitem=%d", aux->type);
+		switch (aux->type) {
+		case AUDIT_AUX_IPCPERM: {
+			struct audit_aux_data_ipcctl *axi = (void *)aux;
+			audit_log_format(ab, 
+					 " qbytes=%lx uid=%d gid=%d mode=%x",
+					 axi->qbytes, axi->uid, axi->gid, axi->mode);
+			}
+		}
+		audit_log_end(ab);
+		kfree(aux);
+	}
+
 	for (i = 0; i < context->name_count; i++) {
 		ab = audit_log_start(context);
 		if (!ab)
@@ -867,6 +919,7 @@ void audit_syscall_exit(struct task_stru
 	} else {
 		audit_free_names(context);
 		audit_free_files(context);
+		audit_free_aux(context);
 		audit_zero_context(context, context->state);
 		tsk->audit_context = context;
 	}
@@ -1049,3 +1102,26 @@ int audit_notify_watch(struct inode *ino
 	return 0;
 }
 
+int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode)
+{
+	struct audit_aux_data_ipcctl *ax;
+	struct audit_context *context = current->audit_context;
+
+	if (likely(!context))
+		return 0;
+
+	ax = kmalloc(sizeof(*ax), GFP_KERNEL);
+	if (!ax)
+		return -ENOMEM;
+
+	ax->qbytes = qbytes;
+	ax->uid = uid;
+	ax->gid = gid;
+	ax->mode = mode;
+
+	ax->d.type = AUDIT_AUX_IPCPERM;
+	ax->d.next = context->aux; /* Do we need locking? Can anyone else walk this list */
+	context->aux = ax->d.next; /* while we're mucking about with it? I think not. dwmw2 */
+
+	return 0;
+}
--- linux-2.6.9/ipc/msg.c~	2004-10-18 22:53:06.000000000 +0100
+++ linux-2.6.9/ipc/msg.c	2005-02-01 17:28:28.155088688 +0000
@@ -24,6 +24,7 @@
 #include <linux/list.h>
 #include <linux/security.h>
 #include <linux/sched.h>
+#include <linux/audit.h>
 #include <asm/current.h>
 #include <asm/uaccess.h>
 #include "util.h"
@@ -424,6 +425,8 @@ asmlinkage long sys_msgctl (int msqid, i
 			return -EFAULT;
 		if (copy_msqid_from_user (&setbuf, buf, version))
 			return -EFAULT;
+		if ((err = audit_ipc_perms(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode)))
+			return err;
 		break;
 	case IPC_RMID:
 		break;
--- linux-2.6.9/ipc/sem.c~	2004-10-18 22:53:50.000000000 +0100
+++ linux-2.6.9/ipc/sem.c	2005-02-01 17:28:32.748056160 +0000
@@ -71,6 +71,7 @@
 #include <linux/time.h>
 #include <linux/smp_lock.h>
 #include <linux/security.h>
+#include <linux/audit.h>
 #include <asm/uaccess.h>
 #include "util.h"
 
@@ -788,6 +789,8 @@ static int semctl_down(int semid, int se
 	if(cmd == IPC_SET) {
 		if(copy_semid_from_user (&setbuf, arg.buf, version))
 			return -EFAULT;
+		if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
+			return err;
 	}
 	sma = sem_lock(semid);
 	if(sma==NULL)
--- linux-2.6.9/ipc/shm.c~	2004-10-18 22:54:08.000000000 +0100
+++ linux-2.6.9/ipc/shm.c	2005-02-01 17:28:36.766111032 +0000
@@ -26,6 +26,7 @@
 #include <linux/proc_fs.h>
 #include <linux/shmem_fs.h>
 #include <linux/security.h>
+#include <linux/audit.h>
 #include <asm/uaccess.h>
 
 #include "util.h"
@@ -594,6 +595,8 @@ asmlinkage long sys_shmctl (int shmid, i
 			err = -EFAULT;
 			goto out;
 		}
+		if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
+			return err;
 		down(&shm_ids.sem);
 		shp = shm_lock(shmid);
 		err=-EINVAL;
--- linux-2.6.9/include/linux/audit.h~	2005-01-31 13:22:07.000000000 +0000
+++ linux-2.6.9/include/linux/audit.h	2005-02-01 16:45:38.011083672 +0000
@@ -179,6 +179,7 @@ extern void audit_get_stamp(struct audit
 extern int  audit_set_loginuid(struct audit_context *ctx, uid_t loginuid);
 extern uid_t audit_get_loginuid(struct audit_context *ctx);
 extern int audit_notify_watch(struct inode *inode, int mask);
+extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode);
 #else
 #define audit_alloc(t) ({ 0; })
 #define audit_free(t) do { ; } while (0)
@@ -189,6 +190,7 @@ extern int audit_notify_watch(struct ino
 #define audit_inode(n,i,d) do { ; } while (0)
 #define audit_get_loginuid(c) ({ -1; })
 #define audit_notify_watch(t,i,m) ({ 0; })
+#define audit_ipc_perms(q, u, g, m) do ({ 0; })
 #endif
 
 


-- 
dwmw2


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