X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=procprotect.c;h=1c3e8035e01f840e61fe6e1e74742835b3e6ed6e;hb=45362125880411ebb94253979d98df1b04a3e02c;hp=d49a41b372170a1fe627f047b0e7b6e5f19cf40c;hpb=eb602e2ed7a3b723feb4be26f19b333d1ac88462;p=procprotect.git

diff --git a/procprotect.c b/procprotect.c
index d49a41b..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);
@@ -45,181 +53,333 @@ MODULE_LICENSE("GPL");
 MODULE_VERSION(VERSION_STR);
 
 struct procprotect_ctx {
-	struct inode **inode;
+    struct inode **inode;
+    struct qstr *q;
+    struct path *path;
+    int flags;
 };
 
 struct acl_entry {
-	unsigned int ino;
-	struct hlist_node hlist;
+    unsigned int ino;
+    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) {
-	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;
+   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 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 dentry *parent;
+    struct inode *pinode;
 	
-	if (pinode->i_sb->s_magic == PROC_SUPER_MAGIC) {	
-		ctx = (struct procprotect_ctx *) ri->data;
-		ctx->inode = (struct inode **) regs->cx;
-		ret = 0;
-	}
+	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->dx;
+        ctx->flags = nd->flags;
+        ret = 0;
+    }
 
-	return ret;
+    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 */
+
+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;
+
+    if (ret==0) {
+        /* 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)) {
+            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 */
+   accesses to /proc */
 
-static int do_lookup_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
+static int print_once = 0;
+
+static int lookup_slow_ret(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
-	struct procprotect_ctx *ctx = (struct procprotect_ctx *) ri->data;
-	int ret = regs->ax;
-	
-	if (ret==0) {
-		/* The kernel is going to honor the request. Here's where we step in */
-		struct inode *inode = *(ctx->inode);
-		//printk(KERN_CRIT "Checking inode %x number %u",inode,inode->i_ino);
-		if (!run_acl(inode->i_ino)) {
-			if (current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns)
-				regs->ax = -EPERM;
-		}
-	}
-	
-	return 0;
+    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;
+        }
+    }
+
+    return 0;
 }
 
-static struct kretprobe proc_probe = {
-	.entry_handler = (kprobe_opcode_t *) do_lookup_entry,
-        .handler = (kprobe_opcode_t *) do_lookup_ret,
-	.maxactive = 20,
-	.data_size = sizeof(struct procprotect_ctx)
+struct open_flags {
+  int open_flag;
+  umode_t mode;
+  int acc_mode;
+  int intent;
 };
 
-static void add_entry(char *pathname) {
-	struct path path;
-	if (kern_path(pathname, 0, &path)) {
-		printk(KERN_CRIT "Path lookup failed for %s",pathname);
-	}	
-	else {
-		unsigned int ino = path.dentry->d_inode->i_ino;
-		struct acl_entry *entry;
-		entry = kmalloc(GFP_KERNEL, sizeof(struct acl_entry));
-		entry->ino = ino;
-		
-		if (!entry) {
-			printk(KERN_CRIT "Could not allocate memory for %s",pathname);
-		}
-		else {
-			if (run_acl(ino)) {
-				hlist_add_head_rcu(&entry->hlist,&procprotect_hash[ino&(HASH_SIZE-1)]);
-				printk(KERN_CRIT "Added inode %u",ino);
-			}
-			else {
-				printk(KERN_CRIT "Did not add inode %u, already in list", ino);
-			}
-		}
+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();
+}
+
+static struct jprobe dolast_probe = {
+	.entry = (kprobe_opcode_t *) do_last_probe
+};
+
+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)) {
+        printk(KERN_CRIT "Path lookup failed for %s",pathname);
+    }	
+    else {
+        unsigned int ino = path.dentry->d_inode->i_ino;
+        struct acl_entry *entry;
+        entry = kmalloc(GFP_KERNEL, sizeof(struct acl_entry));
+        entry->ino = ino;
+
+        if (!entry) {
+            printk(KERN_CRIT "Could not allocate memory for %s",pathname);
+        }
+        else {
+            if (run_acl(ino)) {
+                hlist_add_head_rcu(&entry->hlist,&procprotect_hash[ino&(HASH_SIZE-1)]);
+                printk(KERN_CRIT "Added inode %u",ino);
+            }
+            else {
+                printk(KERN_CRIT "Did not add inode %u, already in list", ino);
+            }
+        }
+    }
+
 }
 
 
 static void __exit procprotect_exit(void)
 {
-	unregister_kretprobe(&proc_probe);
-	struct hlist_node *n;
-	struct acl_entry *entry;
-	int i;
-
-	for (i=0;i<HASH_SIZE;i++) {
-		hlist_for_each_entry_rcu(entry, 
-			n, &procprotect_hash[i],
-			hlist) {
-				kfree(entry);
-		}
-	}
-	
-	remove_proc_entry("procprotect",NULL);
-	printk("Procprotect: Stopped procprotect.\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, 
+				 &procprotect_hash[i],
+				 hlist) {
+            kfree(entry);
+        }
+    }
+
+    remove_proc_entry("procprotect",NULL);
+    printk("Procprotect: Stopped procprotect.\n");
 }
 
 
 
 int procfile_write(struct file *file, const char *buffer, unsigned long count, void *data) {		
-	char pathname[PATH_MAX];
+    char pathname[PATH_MAX];
 
-	if (current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns)
-		return -EPERM;
+    if (current->nsproxy->mnt_ns!=init_task.nsproxy->mnt_ns)
+        return -EPERM;
 
-	if (copy_from_user(pathname, buffer, count)) {
-		return -EFAULT;
-	}
-	if (count && (pathname[count-1]==10 || pathname[count-1]==13)) {
-		pathname[count-1]='\0';
+    if (copy_from_user(pathname, buffer, count)) {
+        return -EFAULT;
+    }
+    if (count && (pathname[count-1]==10 || pathname[count-1]==13)) {
+        pathname[count-1]='\0';
+    }
+    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.");
 	}
-	else
-		pathname[count]='\0';
-	add_entry(pathname);	
-	printk(KERN_CRIT "Length of buffer=%d",strlen(pathname));
-	return count;
+    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;
+    int ret;
+    int i;
 
-	for(i=0;i<HASH_SIZE;i++) {
-		INIT_HLIST_HEAD(&procprotect_hash[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]);
+    }
+
+    aclqpath.name = aclpath;
+    aclqpath.len = strnlen(aclpath, PATH_MAX);
+
+    proc_entry = proc_create("procprotect", 0644, NULL, &procprotect_fops);
 
-	  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;
-          }
-  
-          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;
-        return ret;
+    return ret;
 }