[PATCH] new predicate - AUDIT_FILETYPE

Argument is S_IF... | <index>, where index is normally 0 or 1.
Triggers if chosen element of ctx->names[] is present and the
mode of object in question matches the upper bits of argument.
I.e. for things like "is the argument of that chmod a directory",
etc.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 25 insertions, 0 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index dcd5395b400d..63c3bb98558f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -209,6 +209,7 @@
 #define AUDIT_WATCH     105
 #define AUDIT_PERM      106
 #define AUDIT_DIR       107
+#define AUDIT_FILETYPE  108
 
 #define AUDIT_ARG0      200
 #define AUDIT_ARG1      (AUDIT_ARG0+1)
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 7c3450d063fe..9435d9392df5 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -478,6 +478,10 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
                         if (f->val & ~15)
                                 goto exit_free;
                         break;
+                case AUDIT_FILETYPE:
+                        if ((f->val & ~S_IFMT) > S_IFMT)
+                                goto exit_free;
+                        break;
                 case AUDIT_INODE:
                         err = audit_to_inode(&entry->rule, f);
                         if (err)
@@ -649,6 +653,10 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
                         if (f->val & ~15)
                                 goto exit_free;
                         break;
+                case AUDIT_FILETYPE:
+                        if ((f->val & ~S_IFMT) > S_IFMT)
+                                goto exit_free;
+                        break;
                 default:
                         goto exit_free;
                 }
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 091409996577..c10e7aae04d7 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -280,6 +280,19 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
         }
 }
 
+static int audit_match_filetype(struct audit_context *ctx, int which)
+{
+        unsigned index = which & ~S_IFMT;
+        mode_t mode = which & S_IFMT;
+        if (index >= ctx->name_count)
+                return 0;
+        if (ctx->names[index].ino == -1)
+                return 0;
+        if ((ctx->names[index].mode ^ mode) & S_IFMT)
+                return 0;
+        return 1;
+}
+
 /*
  * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
  * ->first_trees points to its beginning, ->trees - to the current end of data.
@@ -589,6 +602,9 @@ static int audit_filter_rules(struct task_struct *tsk,
                 case AUDIT_PERM:
                         result = audit_match_perm(ctx, f->val);
                         break;
+                case AUDIT_FILETYPE:
+                        result = audit_match_filetype(ctx, f->val);
+                        break;
                 }
 
                 if (!result)