[ARM] nommu: Provide a simple flush_dcache_page implementation
[linux-3.10.git] / security / seclvl.c
index 8529ea6..441beaf 100644 (file)
@@ -8,6 +8,7 @@
  * Copyright (c) 2001 WireX Communications, Inc <chris@wirex.com>
  * Copyright (c) 2001 Greg Kroah-Hartman <greg@kroah.com>
  * Copyright (c) 2002 International Business Machines <robb@austin.ibm.com>
+ * Copyright (c) 2006 Davi E. M. Arnaut <davi.arnaut@gmail.com>
  *
  *     This program is free software; you can redistribute it and/or modify
  *     it under the terms of the GNU General Public License as published by
@@ -31,6 +32,7 @@
 #include <linux/kobject.h>
 #include <linux/crypto.h>
 #include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 #include <linux/gfp.h>
 #include <linux/sysfs.h>
 
@@ -194,35 +196,27 @@ static unsigned char hashedPassword[SHA1_DIGEST_SIZE];
  * people...
  */
 static int
-plaintext_to_sha1(unsigned char *hash, const char *plaintext, int len)
+plaintext_to_sha1(unsigned char *hash, const char *plaintext, unsigned int len)
 {
-       char *pgVirtAddr;
        struct crypto_tfm *tfm;
-       struct scatterlist sg[1];
+       struct scatterlist sg;
        if (len > PAGE_SIZE) {
                seclvl_printk(0, KERN_ERR, "Plaintext password too large (%d "
                              "characters).  Largest possible is %lu "
                              "bytes.\n", len, PAGE_SIZE);
-               return -ENOMEM;
+               return -EINVAL;
        }
        tfm = crypto_alloc_tfm("sha1", CRYPTO_TFM_REQ_MAY_SLEEP);
        if (tfm == NULL) {
                seclvl_printk(0, KERN_ERR,
                              "Failed to load transform for SHA1\n");
-               return -ENOSYS;
+               return -EINVAL;
        }
-       // Just get a new page; don't play around with page boundaries
-       // and scatterlists.
-       pgVirtAddr = (char *)__get_free_page(GFP_KERNEL);
-       sg[0].page = virt_to_page(pgVirtAddr);
-       sg[0].offset = 0;
-       sg[0].length = len;
-       strncpy(pgVirtAddr, plaintext, len);
+       sg_init_one(&sg, (u8 *)plaintext, len);
        crypto_digest_init(tfm);
-       crypto_digest_update(tfm, sg, 1);
+       crypto_digest_update(tfm, &sg, 1);
        crypto_digest_final(tfm, hash);
        crypto_free_tfm(tfm);
-       free_page((unsigned long)pgVirtAddr);
        return 0;
 }
 
@@ -234,11 +228,9 @@ static ssize_t
 passwd_write_file(struct file * file, const char __user * buf,
                                size_t count, loff_t *ppos)
 {
-       int i;
-       unsigned char tmp[SHA1_DIGEST_SIZE];
-       char *page;
-       int rc;
+       char *p;
        int len;
+       unsigned char tmp[SHA1_DIGEST_SIZE];
 
        if (!*passwd && !*sha1_passwd) {
                seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the "
@@ -251,38 +243,39 @@ passwd_write_file(struct file * file, const char __user * buf,
                return -EINVAL;
        }
 
-       if (count < 0 || count >= PAGE_SIZE)
+       if (count >= PAGE_SIZE)
                return -EINVAL;
        if (*ppos != 0)
                return -EINVAL;
-       page = (char *)get_zeroed_page(GFP_KERNEL);
-       if (!page)
+       p = kmalloc(count, GFP_KERNEL);
+       if (!p)
                return -ENOMEM;
        len = -EFAULT;
-       if (copy_from_user(page, buf, count))
+       if (copy_from_user(p, buf, count))
                goto out;
        
-       len = strlen(page);
+       len = count;
        /* ``echo "secret" > seclvl/passwd'' includes a newline */
-       if (page[len - 1] == '\n')
+       if (p[len - 1] == '\n')
                len--;
        /* Hash the password, then compare the hashed values */
-       if ((rc = plaintext_to_sha1(tmp, page, len))) {
+       if ((len = plaintext_to_sha1(tmp, p, len))) {
                seclvl_printk(0, KERN_ERR, "Error hashing password: rc = "
-                             "[%d]\n", rc);
-               return rc;
-       }
-       for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
-               if (hashedPassword[i] != tmp[i])
-                       return -EPERM;
+                             "[%d]\n", len);
+               goto out;
        }
+
+       len = -EPERM;
+       if (memcmp(hashedPassword, tmp, SHA1_DIGEST_SIZE))
+               goto out;
+
        seclvl_printk(0, KERN_INFO,
                      "Password accepted; seclvl reduced to 0.\n");
        seclvl = 0;
        len = count;
 
 out:
-       free_page((unsigned long)page);
+       kfree (p);
        return len;
 }
 
@@ -295,13 +288,11 @@ static struct file_operations passwd_file_ops = {
  */
 static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child)
 {
-       if (seclvl >= 0) {
-               if (child->pid == 1) {
-                       seclvl_printk(1, KERN_WARNING, "Attempt to ptrace "
-                                     "the init process dissallowed in "
-                                     "secure level %d\n", seclvl);
-                       return -EPERM;
-               }
+       if (seclvl >= 0 && child->pid == 1) {
+               seclvl_printk(1, KERN_WARNING, "Attempt to ptrace "
+                             "the init process dissallowed in "
+                             "secure level %d\n", seclvl);
+               return -EPERM;
        }
        return 0;
 }
@@ -312,55 +303,54 @@ static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child)
  */
 static int seclvl_capable(struct task_struct *tsk, int cap)
 {
+       int rc = 0;
+
        /* init can do anything it wants */
        if (tsk->pid == 1)
                return 0;
 
-       switch (seclvl) {
-       case 2:
-               /* fall through */
-       case 1:
-               if (cap == CAP_LINUX_IMMUTABLE) {
+       if (seclvl > 0) {
+               rc = -EPERM;
+
+               if (cap == CAP_LINUX_IMMUTABLE)
                        seclvl_printk(1, KERN_WARNING, "Attempt to modify "
                                      "the IMMUTABLE and/or APPEND extended "
                                      "attribute on a file with the IMMUTABLE "
                                      "and/or APPEND extended attribute set "
                                      "denied in seclvl [%d]\n", seclvl);
-                       return -EPERM;
-               } else if (cap == CAP_SYS_RAWIO) {      // Somewhat broad...
+               else if (cap == CAP_SYS_RAWIO)
                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
                                      "raw I/O while in secure level [%d] "
                                      "denied\n", seclvl);
-                       return -EPERM;
-               } else if (cap == CAP_NET_ADMIN) {
+               else if (cap == CAP_NET_ADMIN)
                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
                                      "network administrative task while "
                                      "in secure level [%d] denied\n", seclvl);
-                       return -EPERM;
-               } else if (cap == CAP_SETUID) {
+               else if (cap == CAP_SETUID)
                        seclvl_printk(1, KERN_WARNING, "Attempt to setuid "
                                      "while in secure level [%d] denied\n",
                                      seclvl);
-                       return -EPERM;
-               } else if (cap == CAP_SETGID) {
+               else if (cap == CAP_SETGID)
                        seclvl_printk(1, KERN_WARNING, "Attempt to setgid "
                                      "while in secure level [%d] denied\n",
                                      seclvl);
-               } else if (cap == CAP_SYS_MODULE) {
+               else if (cap == CAP_SYS_MODULE)
                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
                                      "a module operation while in secure "
                                      "level [%d] denied\n", seclvl);
-                       return -EPERM;
-               }
-               break;
-       default:
-               break;
+               else
+                       rc = 0;
        }
-       /* from dummy.c */
-       if (cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0)
-               return 0;       /* capability granted */
-       seclvl_printk(1, KERN_WARNING, "Capability denied\n");
-       return -EPERM;          /* capability denied */
+
+       if (!rc) {
+               if (!(cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0))
+                       rc = -EPERM;
+       }
+
+       if (rc)
+               seclvl_printk(1, KERN_WARNING, "Capability denied\n");
+
+       return rc;
 }
 
 /**
@@ -466,12 +456,9 @@ static int seclvl_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 static void seclvl_file_free_security(struct file *filp)
 {
        struct dentry *dentry = filp->f_dentry;
-       struct inode *inode = NULL;
 
-       if (dentry) {
-               inode = dentry->d_inode;
-               seclvl_bd_release(inode);
-       }
+       if (dentry)
+               seclvl_bd_release(dentry->d_inode);
 }
 
 /**
@@ -479,9 +466,7 @@ static void seclvl_file_free_security(struct file *filp)
  */
 static int seclvl_umount(struct vfsmount *mnt, int flags)
 {
-       if (current->pid == 1)
-               return 0;
-       if (seclvl == 2) {
+       if (current->pid != 1 && seclvl == 2) {
                seclvl_printk(1, KERN_WARNING, "Attempt to unmount in secure "
                              "level %d\n", seclvl);
                return -EPERM;
@@ -505,8 +490,9 @@ static struct security_operations seclvl_ops = {
 static int processPassword(void)
 {
        int rc = 0;
-       hashedPassword[0] = '\0';
        if (*passwd) {
+               char *p;
+
                if (*sha1_passwd) {
                        seclvl_printk(0, KERN_ERR, "Error: Both "
                                      "passwd and sha1_passwd "
@@ -514,12 +500,16 @@ static int processPassword(void)
                                      "exclusive.\n");
                        return -EINVAL;
                }
-               if ((rc = plaintext_to_sha1(hashedPassword, passwd,
-                                           strlen(passwd)))) {
+
+               p = kstrdup(passwd, GFP_KERNEL);
+               if (p == NULL)
+                       return -ENOMEM;
+
+               if ((rc = plaintext_to_sha1(hashedPassword, p, strlen(p))))
                        seclvl_printk(0, KERN_ERR, "Error: SHA1 support not "
                                      "in kernel\n");
-                       return rc;
-               }
+
+               kfree (p);
                /* All static data goes to the BSS, which zero's the
                 * plaintext password out for us. */
        } else if (*sha1_passwd) {      // Base 16
@@ -542,7 +532,7 @@ static int processPassword(void)
                        sha1_passwd[i + 2] = tmp;
                }
        }
-       return 0;
+       return rc;
 }
 
 /**
@@ -552,28 +542,46 @@ struct dentry *dir_ino, *seclvl_ino, *passwd_ino;
 
 static int seclvlfs_register(void)
 {
+       int rc = 0;
+
        dir_ino = securityfs_create_dir("seclvl", NULL);
-       if (!dir_ino)
-               return -EFAULT;
+
+       if (IS_ERR(dir_ino))
+               return PTR_ERR(dir_ino);
 
        seclvl_ino = securityfs_create_file("seclvl", S_IRUGO | S_IWUSR,
                                dir_ino, &seclvl, &seclvl_file_ops);
-       if (!seclvl_ino)
+       if (IS_ERR(seclvl_ino)) {
+               rc = PTR_ERR(seclvl_ino);
                goto out_deldir;
+       }
        if (*passwd || *sha1_passwd) {
                passwd_ino = securityfs_create_file("passwd", S_IRUGO | S_IWUSR,
                                dir_ino, NULL, &passwd_file_ops);
-               if (!passwd_ino)
+               if (IS_ERR(passwd_ino)) {
+                       rc = PTR_ERR(passwd_ino);
                        goto out_delf;
+               }
        }
-       return 0;
+       return rc;
+
+out_delf:
+       securityfs_remove(seclvl_ino);
 
 out_deldir:
        securityfs_remove(dir_ino);
-out_delf:
+
+       return rc;
+}
+
+static void seclvlfs_unregister(void)
+{
        securityfs_remove(seclvl_ino);
 
-       return -EFAULT;
+       if (*passwd || *sha1_passwd)
+               securityfs_remove(passwd_ino);
+
+       securityfs_remove(dir_ino);
 }
 
 /**
@@ -582,6 +590,8 @@ out_delf:
 static int __init seclvl_init(void)
 {
        int rc = 0;
+       static char once;
+
        if (verbosity < 0 || verbosity > 1) {
                printk(KERN_ERR "Error: bad verbosity [%d]; only 0 or 1 "
                       "are valid values\n", verbosity);
@@ -600,6 +610,11 @@ static int __init seclvl_init(void)
                              "module parameter(s): rc = [%d]\n", rc);
                goto exit;
        }
+
+       if ((rc = seclvlfs_register())) {
+               seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
+               goto exit;
+       }
        /* register ourselves with the security framework */
        if (register_security(&seclvl_ops)) {
                seclvl_printk(0, KERN_ERR,
@@ -611,20 +626,24 @@ static int __init seclvl_init(void)
                        seclvl_printk(0, KERN_ERR, "seclvl: Failure "
                                      "registering with primary security "
                                      "module.\n");
+                       seclvlfs_unregister();
                        goto exit;
                }               /* if primary module registered */
                secondary = 1;
        }                       /* if we registered ourselves with the security framework */
-       if ((rc = seclvlfs_register())) {
-               seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
-               goto exit;
-       }
+
        seclvl_printk(0, KERN_INFO, "seclvl: Successfully initialized.\n");
+
+       if (once) {
+               once = 1;
+               seclvl_printk(0, KERN_INFO, "seclvl is going away. It has been "
+                               "buggy for ages. Also, be warned that "
+                               "Securelevels are useless.");
+       }
  exit:
-       if (rc) {
+       if (rc)
                printk(KERN_ERR "seclvl: Error during initialization: rc = "
                       "[%d]\n", rc);
-       }
        return rc;
 }
 
@@ -633,17 +652,14 @@ static int __init seclvl_init(void)
  */
 static void __exit seclvl_exit(void)
 {
-       securityfs_remove(seclvl_ino);
-       if (*passwd || *sha1_passwd)
-               securityfs_remove(passwd_ino);
-       securityfs_remove(dir_ino);
-       if (secondary == 1) {
+       seclvlfs_unregister();
+
+       if (secondary)
                mod_unreg_security(MY_NAME, &seclvl_ops);
-       } else if (unregister_security(&seclvl_ops)) {
+       else if (unregister_security(&seclvl_ops))
                seclvl_printk(0, KERN_INFO,
                              "seclvl: Failure unregistering with the "
                              "kernel\n");
-       }
 }
 
 module_init(seclvl_init);