diff options
| -rw-r--r-- | security/seclvl.c | 210 |
1 files changed, 113 insertions, 97 deletions
diff --git a/security/seclvl.c b/security/seclvl.c index 8529ea6..441beaf 100644 --- a/security/seclvl.c +++ b/security/seclvl.c @@ -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); |
