[PATCH] log more info for directory entry change events

When an audit event involves changes to a directory entry, include
a PATH record for the directory itself.  A few other notable changes:

    - fixed audit_inode_child() hooks in fsnotify_move()
    - removed unused flags arg from audit_inode()
    - added audit log routines for logging a portion of a string

Here's some sample output.

before patch:
type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255
type=CWD msg=audit(1149821605.320:26):  cwd="/root"
type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0

after patch:
type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255
type=CWD msg=audit(1149822032.332:24):  cwd="/root"
type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0
type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0

Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 69 insertions, 54 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 174a3f624892..851ae0217e4b 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -82,6 +82,9 @@ extern int audit_enabled;
  * path_lookup. */
 #define AUDIT_NAMES_RESERVED 7
 
+/* Indicates that audit should log the full pathname. */
+#define AUDIT_NAME_FULL -1
+
 /* When fs/namei.c:getname() is called, we store the pointer in name and
  * we don't let putname() free it (instead we free all of the saved
  * pointers at syscall exit time).
@@ -89,8 +92,9 @@ extern int audit_enabled;
  * Further, in fs/namei.c:path_lookup() we store the inode and device. */
 struct audit_names {
         const char      *name;
+        int             name_len;       /* number of name's characters to log */
+        unsigned        name_put;       /* call __putname() for this name */
         unsigned long   ino;
-        unsigned long   pino;
         dev_t           dev;
         umode_t         mode;
         uid_t           uid;
@@ -296,12 +300,10 @@ static int audit_filter_rules(struct task_struct *tsk,
                         break;
                 case AUDIT_INODE:
                         if (name)
-                                result = (name->ino == f->val ||
-                                          name->pino == f->val);
+                                result = (name->ino == f->val);
                         else if (ctx) {
                                 for (j = 0; j < ctx->name_count; j++) {
-                                        if (audit_comparator(ctx->names[j].ino, f->op, f->val) ||
-                                            audit_comparator(ctx->names[j].pino, f->op, f->val)) {
+                                        if (audit_comparator(ctx->names[j].ino, f->op, f->val)) {
                                                 ++result;
                                                 break;
                                         }
@@ -311,8 +313,7 @@ static int audit_filter_rules(struct task_struct *tsk,
                 case AUDIT_WATCH:
                         if (name && rule->watch->ino != (unsigned long)-1)
                                 result = (name->dev == rule->watch->dev &&
-                                          (name->ino == rule->watch->ino ||
-                                           name->pino == rule->watch->ino));
+                                          name->ino == rule->watch->ino);
                         break;
                 case AUDIT_LOGINUID:
                         result = 0;
@@ -526,7 +527,7 @@ static inline void audit_free_names(struct audit_context *context)
 #endif
 
         for (i = 0; i < context->name_count; i++) {
-                if (context->names[i].name)
+                if (context->names[i].name && context->names[i].name_put)
                         __putname(context->names[i].name);
         }
         context->name_count = 0;
@@ -850,8 +851,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
                 }
         }
         for (i = 0; i < context->name_count; i++) {
-                unsigned long ino  = context->names[i].ino;
-                unsigned long pino = context->names[i].pino;
+                struct audit_names *n = &context->names[i];
 
                 ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
                 if (!ab)
@@ -859,33 +859,47 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
 
                 audit_log_format(ab, "item=%d", i);
 
-                audit_log_format(ab, " name=");
-                if (context->names[i].name)
-                        audit_log_untrustedstring(ab, context->names[i].name);
-                else
-                        audit_log_format(ab, "(null)");
-
-                if (pino != (unsigned long)-1)
-                        audit_log_format(ab, " parent=%lu",  pino);
-                if (ino != (unsigned long)-1)
-                        audit_log_format(ab, " inode=%lu",  ino);
-                if ((pino != (unsigned long)-1) || (ino != (unsigned long)-1))
-                        audit_log_format(ab, " dev=%02x:%02x mode=%#o" 
-                                         " ouid=%u ogid=%u rdev=%02x:%02x", 
-                                         MAJOR(context->names[i].dev), 
-                                         MINOR(context->names[i].dev), 
-                                         context->names[i].mode, 
-                                         context->names[i].uid, 
-                                         context->names[i].gid, 
-                                         MAJOR(context->names[i].rdev), 
-                                         MINOR(context->names[i].rdev));
-                if (context->names[i].osid != 0) {
+                if (n->name) {
+                        switch(n->name_len) {
+                        case AUDIT_NAME_FULL:
+                                /* log the full path */
+                                audit_log_format(ab, " name=");
+                                audit_log_untrustedstring(ab, n->name);
+                                break;
+                        case 0:
+                                /* name was specified as a relative path and the
+                                 * directory component is the cwd */
+                                audit_log_d_path(ab, " name=", context->pwd,
+                                                 context->pwdmnt);
+                                break;
+                        default:
+                                /* log the name's directory component */
+                                audit_log_format(ab, " name=");
+                                audit_log_n_untrustedstring(ab, n->name_len,
+                                                            n->name);
+                        }
+                } else
+                        audit_log_format(ab, " name=(null)");
+
+                if (n->ino != (unsigned long)-1) {
+                        audit_log_format(ab, " inode=%lu"
+                                         " dev=%02x:%02x mode=%#o"
+                                         " ouid=%u ogid=%u rdev=%02x:%02x",
+                                         n->ino,
+                                         MAJOR(n->dev),
+                                         MINOR(n->dev),
+                                         n->mode,
+                                         n->uid,
+                                         n->gid,
+                                         MAJOR(n->rdev),
+                                         MINOR(n->rdev));
+                }
+                if (n->osid != 0) {
                         char *ctx = NULL;
                         u32 len;
                         if (selinux_ctxid_to_string(
-                                context->names[i].osid, &ctx, &len)) {
-                                audit_log_format(ab, " osid=%u",
-                                                context->names[i].osid);
+                                n->osid, &ctx, &len)) {
+                                audit_log_format(ab, " osid=%u", n->osid);
                                 call_panic = 2;
                         } else
                                 audit_log_format(ab, " obj=%s", ctx);
@@ -1075,6 +1089,8 @@ void __audit_getname(const char *name)
         }
         BUG_ON(context->name_count >= AUDIT_NAMES);
         context->names[context->name_count].name = name;
+        context->names[context->name_count].name_len = AUDIT_NAME_FULL;
+        context->names[context->name_count].name_put = 1;
         context->names[context->name_count].ino  = (unsigned long)-1;
         ++context->name_count;
         if (!context->pwd) {
@@ -1141,11 +1157,10 @@ static void audit_inode_context(int idx, const struct inode *inode)
  * audit_inode - store the inode and device from a lookup
  * @name: name being audited
  * @inode: inode being audited
- * @flags: lookup flags (as used in path_lookup())
  *
  * Called from fs/namei.c:path_lookup().
  */
-void __audit_inode(const char *name, const struct inode *inode, unsigned flags)
+void __audit_inode(const char *name, const struct inode *inode)
 {
         int idx;
         struct audit_context *context = current->audit_context;
@@ -1171,20 +1186,13 @@ void __audit_inode(const char *name, const struct inode *inode, unsigned flags)
                 ++context->ino_count;
 #endif
         }
+        context->names[idx].ino   = inode->i_ino;
         context->names[idx].dev   = inode->i_sb->s_dev;
         context->names[idx].mode  = inode->i_mode;
         context->names[idx].uid   = inode->i_uid;
         context->names[idx].gid   = inode->i_gid;
         context->names[idx].rdev  = inode->i_rdev;
         audit_inode_context(idx, inode);
-        if ((flags & LOOKUP_PARENT) && (strcmp(name, "/") != 0) && 
-            (strcmp(name, ".") != 0)) {
-                context->names[idx].ino   = (unsigned long)-1;
-                context->names[idx].pino  = inode->i_ino;
-        } else {
-                context->names[idx].ino   = inode->i_ino;
-                context->names[idx].pino  = (unsigned long)-1;
-        }
 }
 
 /**
@@ -1206,34 +1214,40 @@ void __audit_inode_child(const char *dname, const struct inode *inode,
 {
         int idx;
         struct audit_context *context = current->audit_context;
+        const char *found_name = NULL;
+        int dirlen = 0;
 
         if (!context->in_syscall)
                 return;
 
         /* determine matching parent */
         if (!dname)
-                goto no_match;
+                goto update_context;
         for (idx = 0; idx < context->name_count; idx++)
-                if (context->names[idx].pino == pino) {
+                if (context->names[idx].ino == pino) {
                         const char *name = context->names[idx].name;
 
                         if (!name)
                                 continue;
 
-                        if (audit_compare_dname_path(dname, name) == 0)
-                                goto update_context;
+                        if (audit_compare_dname_path(dname, name, &dirlen) == 0) {
+                                context->names[idx].name_len = dirlen;
+                                found_name = name;
+                                break;
+                        }
                 }
 
-no_match:
-        /* catch-all in case match not found */
+update_context:
         idx = context->name_count++;
-        context->names[idx].name  = NULL;
-        context->names[idx].pino  = pino;
 #if AUDIT_DEBUG
         context->ino_count++;
 #endif
+        /* Re-use the name belonging to the slot for a matching parent directory.
+         * All names for this context are relinquished in audit_free_names() */
+        context->names[idx].name = found_name;
+        context->names[idx].name_len = AUDIT_NAME_FULL;
+        context->names[idx].name_put = 0;       /* don't call __putname() */
 
-update_context:
         if (inode) {
                 context->names[idx].ino   = inode->i_ino;
                 context->names[idx].dev   = inode->i_sb->s_dev;
@@ -1242,7 +1256,8 @@ update_context:
                 context->names[idx].gid   = inode->i_gid;
                 context->names[idx].rdev  = inode->i_rdev;
                 audit_inode_context(idx, inode);
-        }
+        } else
+                context->names[idx].ino   = (unsigned long)-1;
 }
 
 /**