X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=procprotect.c;h=1c3e8035e01f840e61fe6e1e74742835b3e6ed6e;hb=45362125880411ebb94253979d98df1b04a3e02c;hp=c1c016273e165ae99607666a3ca62b0033278cfb;hpb=f042ad58bae8446f25e2762fe4de413aad57026f;p=procprotect.git

diff --git a/procprotect.c b/procprotect.c
index c1c0162..1c3e803 100644
--- a/procprotect.c
+++ b/procprotect.c
@@ -2,6 +2,7 @@
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
+#include <linux/version.h>
 #include <linux/fs_struct.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
@@ -27,13 +28,20 @@
 #include <linux/kallsyms.h>
 #include <linux/nsproxy.h>
 
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/module.h>	/* Specifically, a module */
+#include <linux/kernel.h>	/* We're doing kernel work */
+#include <linux/proc_fs.h>	/* Necessary because we use the proc fs */
+
 #define VERSION_STR "0.0.1"
 
 #ifndef CONFIG_X86_64
 #error "This code does not support your architecture"
 #endif
 
-static char *aclpath __devinitdata = "procprotect";
+static char *aclpath = "procprotect";
+
 static struct qstr aclqpath;
 
 module_param(aclpath, charp, 0);
@@ -46,6 +54,8 @@ MODULE_VERSION(VERSION_STR);
 
 struct procprotect_ctx {
     struct inode **inode;
+    struct qstr *q;
+    struct path *path;
     int flags;
 };
 
@@ -54,29 +64,48 @@ struct acl_entry {
     struct hlist_node hlist;
 };
 
-#define HASH_SIZE (1<<16)
+#define HASH_SIZE (1<<10)
 
 struct hlist_head procprotect_hash[HASH_SIZE];
 
 struct proc_dir_entry *proc_entry;
 
+static int run_acl(unsigned long ino) {
+    struct acl_entry *entry;
+    hlist_for_each_entry_rcu_notrace(entry, 
+			     &procprotect_hash[ino & (HASH_SIZE-1)],
+			     hlist) {
+        if (entry->ino==ino) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
 /*
    Entry point of intercepted call. We need to do two things here:
    - Decide if we need the heavier return hook to be called
    - Save the first argument, which is in a register, for consideration in the return hook
    */
-static int do_lookup_entry(struct kretprobe_instance *ri, struct pt_regs *regs) {
+static int lookup_fast_entry(struct kretprobe_instance *ri, struct pt_regs *regs) {
     int ret = -1;
     struct procprotect_ctx *ctx;
     struct nameidata *nd = (struct nameidata *) regs->di;
-    struct qstr *q = (struct qstr *) regs->si;
-    struct dentry *parent = nd->path.dentry;
-    struct inode *pinode = parent->d_inode;
+    struct dentry *parent;
+    struct inode *pinode;
+	
+	if (!nd) return ret;
+	parent = nd->path.dentry;
+
+	if (!parent) return ret;
+	pinode = parent->d_inode;
+
+	if (!pinode || !pinode->i_sb || !current || !current->nsproxy) return ret;
 
     if (pinode->i_sb->s_magic == PROC_SUPER_MAGIC
             && current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns) {	
         ctx = (struct procprotect_ctx *) ri->data;
-        ctx->inode = regs->cx;
+        ctx->inode = regs->dx;
         ctx->flags = nd->flags;
         ret = 0;
     }
@@ -84,23 +113,12 @@ static int do_lookup_entry(struct kretprobe_instance *ri, struct pt_regs *regs)
     return ret;
 }
 
-static int run_acl(unsigned long ino) {
-    struct hlist_node *n;
-    struct acl_entry *entry;
-    hlist_for_each_entry_rcu(entry, 
-            n, &procprotect_hash[ino & (HASH_SIZE-1)],
-            hlist) {
-        if (entry->ino==ino) {
-            return 0;
-        }
-    }
-    return 1;
-}
-
 /* The entry hook ensures that the return hook is only called for
    accesses to /proc */
 
-static int do_lookup_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
+int printed=0;
+
+static int lookup_fast_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
     struct procprotect_ctx *ctx = (struct procprotect_ctx *) ri->data;
     int ret = regs->ax;
@@ -109,9 +127,63 @@ static int do_lookup_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
         /* The kernel is going to honor the request. Here's where we step in */
         struct inode *inode = *(ctx->inode);
         if (!run_acl(inode->i_ino)) {
-            if (current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns) {
-                regs->ax = -EPERM;
-            }
+            regs->ax = -EPERM;
+        }
+    }
+
+
+    return 0;
+}
+
+static int lookup_slow_entry(struct kretprobe_instance *ri, struct pt_regs *regs) {
+    int ret = -1;
+    struct procprotect_ctx *ctx;
+    struct nameidata *nd = (struct nameidata *) regs->di;
+    struct path *p = (struct path *) regs->si;
+    struct dentry *parent;
+	struct inode *pinode;
+
+	if (!nd) return;
+	parent = nd->path.dentry;
+    if (!parent) return;
+	pinode= parent->d_inode;
+
+    if (pinode->i_sb->s_magic == PROC_SUPER_MAGIC
+            && current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns) {	
+        
+        ctx = (struct procprotect_ctx *) ri->data;
+        ctx->q = &nd->last;
+        ctx->flags = nd->flags;
+        ctx->path = p;
+        ret = 0;
+    }
+
+    return ret;
+}
+
+/* The entry hook ensures that the return hook is only called for
+   accesses to /proc */
+
+static int print_once = 0;
+
+static int lookup_slow_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+    struct procprotect_ctx *ctx;
+    int ret;
+
+    if (!ri || !ri->data) {return 0;}
+    ctx = (struct procprotect_ctx *) ri->data;
+
+    ret = regs->ax;
+
+    if (ret==0) {
+        struct path *p = ctx->path;
+        if (!p || !p->dentry || !p->dentry->d_inode /* This last check was responsible for the f18 bug*/) {
+            return 0;
+        }
+        struct inode *inode = p->dentry->d_inode;
+        if (!run_acl(inode->i_ino)) {
+            regs->ax = -EPERM;
         }
     }
 
@@ -125,12 +197,17 @@ struct open_flags {
   int intent;
 };
 
-static struct file *do_last_probe(struct nameidata *nd, struct path *path,
+static struct file *do_last_probe(struct nameidata *nd, struct path *path, struct file *file,
                          struct open_flags *op, const char *pathname) {
     struct dentry *parent = nd->path.dentry;
     struct inode *pinode = parent->d_inode;
+    struct qstr *q = &nd->last;
 
+    
     if (pinode->i_sb->s_magic == PROC_SUPER_MAGIC && current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns) {
+        /*if (!strncmp(q->name,"sysrq-trigger",13)) {
+            printk(KERN_CRIT "do_last sysrqtrigger: %d",op->open_flag);
+        }*/
         op->open_flag &= ~O_CREAT;
     }
     jprobe_return();
@@ -140,13 +217,69 @@ static struct jprobe dolast_probe = {
 	.entry = (kprobe_opcode_t *) do_last_probe
 };
 
-static struct kretprobe proc_probe = {
-    .entry_handler = (kprobe_opcode_t *) do_lookup_entry,
-    .handler = (kprobe_opcode_t *) do_lookup_ret,
+static struct kretprobe fast_probe = {
+    .entry_handler = (kprobe_opcode_t *) lookup_fast_entry,
+    .handler = (kprobe_opcode_t *) lookup_fast_ret,
     .maxactive = 20,
     .data_size = sizeof(struct procprotect_ctx)
 };
 
+static struct kretprobe slow_probe = {
+    .entry_handler = (kprobe_opcode_t *) lookup_slow_entry,
+    .handler = (kprobe_opcode_t *) lookup_slow_ret,
+    .maxactive = 20,
+    .data_size = sizeof(struct procprotect_ctx)
+};
+
+int once_only = 0;
+
+static int init_probes(void) {
+	int ret;
+	dolast_probe.kp.addr = 
+		(kprobe_opcode_t *) kallsyms_lookup_name("do_last");
+
+	if (!dolast_probe.kp.addr) {
+		printk("Couldn't find %s to plant kretprobe\n", "do_last");
+		return -1;
+	}
+
+	if ((ret = register_jprobe(&dolast_probe)) <0) {
+		printk("register_jprobe failed, returned %u\n", ret);
+		return -1;
+	}
+	fast_probe.kp.addr = 
+		(kprobe_opcode_t *) kallsyms_lookup_name("lookup_fast");
+
+	if (!fast_probe.kp.addr) {
+		printk("Couldn't find %s to plant kretprobe\n", "lookup_fast");
+		return -1;
+	}
+
+	slow_probe.kp.addr = 
+		(kprobe_opcode_t *) kallsyms_lookup_name("lookup_slow");
+
+	if (!slow_probe.kp.addr) {
+		printk("Couldn't find %s to plant kretprobe\n", "lookup_slow");
+		return -1;
+	}
+
+	if ((ret = register_kretprobe(&fast_probe)) <0) {
+		printk("register_kretprobe failed, returned %d\n", ret);
+		return -1;
+	}
+
+	printk("Planted kretprobe at %p, handler addr %p\n",
+			fast_probe.kp.addr, fast_probe.handler);
+
+	if ((ret = register_kretprobe(&slow_probe)) <0) {
+		printk("register_kretprobe failed, returned %d\n", ret);
+		return -1;
+	}
+	printk("Planted kretprobe at %p, handler addr %p\n",
+			slow_probe.kp.addr, slow_probe.handler);
+	return 0;
+}
+
 static void add_entry(char *pathname) {
     struct path path;
     if (kern_path(pathname, 0, &path)) {
@@ -171,21 +304,22 @@ static void add_entry(char *pathname) {
             }
         }
     }
+
 }
 
 
 static void __exit procprotect_exit(void)
 {
-    unregister_kretprobe(&proc_probe);
-	unregister_jprobe(&dolast_probe);
-    struct hlist_node *n;
+    unregister_kretprobe(&fast_probe);
+    unregister_kretprobe(&slow_probe);
+    unregister_jprobe(&dolast_probe);    
     struct acl_entry *entry;
     int i;
 
     for (i=0;i<HASH_SIZE;i++) {
         hlist_for_each_entry_rcu(entry, 
-                n, &procprotect_hash[i],
-                hlist) {
+				 &procprotect_hash[i],
+				 hlist) {
             kfree(entry);
         }
     }
@@ -210,18 +344,32 @@ int procfile_write(struct file *file, const char *buffer, unsigned long count, v
     }
     else
         pathname[count]='\0';
+
     add_entry(pathname);	
+		
+	if (!once_only) {
+		once_only=1;
+		if (init_probes()==-1)
+			printk(KERN_CRIT "Could not install procprotect probes. Reload module to retry.");
+	}
     printk(KERN_CRIT "Length of buffer=%d",strlen(pathname));
     return count;
 }
 
+static const struct file_operations procprotect_fops = {
+    .owner = THIS_MODULE,
+    .write = procfile_write
+};
+                          
+
 static int __init procprotect_init(void)
 {
-    printk("Procprotect: starting procprotect version %s with ACLs at path %s.\n",
-            VERSION_STR, aclpath);
     int ret;
     int i;
 
+    printk("Procprotect: starting procprotect version %s with ACLs at path %s.\n",
+            VERSION_STR, aclpath);
+
     for(i=0;i<HASH_SIZE;i++) {
         INIT_HLIST_HEAD(&procprotect_hash[i]);
     }
@@ -229,35 +377,7 @@ static int __init procprotect_init(void)
     aclqpath.name = aclpath;
     aclqpath.len = strnlen(aclpath, PATH_MAX);
 
-    proc_probe.kp.addr = 
-        (kprobe_opcode_t *) kallsyms_lookup_name("do_lookup");
-    if (!proc_probe.kp.addr) {
-        printk("Couldn't find %s to plant kretprobe\n", "do_execve");
-        return -1;
-    }
-
-    dolast_probe.kp.addr = 
-        (kprobe_opcode_t *) kallsyms_lookup_name("do_last");
-
-    if (!dolast_probe.kp.addr) {
-        printk("Couldn't find %s to plant kretprobe\n", "do_last");
-        return -1;
-    }
-
-    if ((ret = register_jprobe(&dolast_probe)) <0) {
-                  printk("register_jprobe failed, returned %u\n", ret);
-                  return -1;
-    }
-
-    if ((ret = register_kretprobe(&proc_probe)) <0) {
-        printk("register_kretprobe failed, returned %d\n", ret);
-        return -1;
-    }
-    printk("Planted kretprobe at %p, handler addr %p\n",
-            proc_probe.kp.addr, proc_probe.handler);
-
-    proc_entry = create_proc_entry("procprotect", 0644, NULL);
-    proc_entry->write_proc = procfile_write;
+    proc_entry = proc_create("procprotect", 0644, NULL, &procprotect_fops);
 
     return ret;
 }