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    SubjectRe: [PATCH] securityfs
    Quoting serue@us.ibm.com (serue@us.ibm.com):
    > Quoting Greg KH (greg@kroah.com):
    > > > Unfortunately the simple_attr code from libfs really doesn't seem to be
    > > > usable for int args.
    > >
    > > Why not? You want a negative number? Just cast the u64 to a signed int
    > > then. Will that not work? If not we can tweak the libfs interface to
    > > work properly for you.
    >
    > Hmm, I ran into two problems:
    > 1, the __simple_attr_check_format seems to complain about a "%d"
    > format.
    > 2, when I try just doing the typecasting, I get an oops...

    Uh, never mind...

    please don't look at that patch :)

    With the obvious fix, that does in fact work (patch appended). The
    __simple_attr_check_format problem remains however. I assume we don't
    really want to just take it out, though, like this patch does? The
    error I get without the fs.h patch is:

    security/seclvl.c: In function `seclvl_file_ops_open':
    security/seclvl.c:186: warning: int format, different type arg (arg 2)

    thanks,
    -serge
    --
    include/linux/fs.h | 1
    security/seclvl.c | 228 ++++++++++++++++-------------------------------------
    2 files changed, 70 insertions(+), 159 deletions(-)

    Index: linux-2.6.13-rc1/include/linux/fs.h
    ===================================================================
    --- linux-2.6.13-rc1.orig/include/linux/fs.h 2005-07-07 15:10:22.000000000 -0500
    +++ linux-2.6.13-rc1/include/linux/fs.h 2005-07-07 17:59:54.000000000 -0500
    @@ -1717,7 +1717,6 @@ static inline void simple_transaction_se
    #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt) \
    static int __fops ## _open(struct inode *inode, struct file *file) \
    { \
    - __simple_attr_check_format(__fmt, 0ull); \
    return simple_attr_open(inode, file, __get, __set, __fmt); \
    } \
    static struct file_operations __fops = { \
    Index: linux-2.6.13-rc1/security/seclvl.c
    ===================================================================
    --- linux-2.6.13-rc1.orig/security/seclvl.c 2005-07-07 15:33:45.000000000 -0500
    +++ linux-2.6.13-rc1/security/seclvl.c 2005-07-07 22:30:45.000000000 -0500
    @@ -119,69 +119,6 @@ MODULE_PARM_DESC(hideHash, "When set to
    } while (0)

    /**
    - * kobject stuff
    - */
    -
    -struct subsystem seclvl_subsys;
    -
    -struct seclvl_obj {
    - char *name;
    - struct list_head slot_list;
    - struct kobject kobj;
    -};
    -
    -/**
    - * There is a seclvl_attribute struct for each file in sysfs.
    - *
    - * In our case, we have one of these structs for "passwd" and another
    - * for "seclvl".
    - */
    -struct seclvl_attribute {
    - struct attribute attr;
    - ssize_t(*show) (struct seclvl_obj *, char *);
    - ssize_t(*store) (struct seclvl_obj *, const char *, size_t);
    -};
    -
    -/**
    - * When this function is called, one of the files in sysfs is being
    - * written to. attribute->store is a function pointer to whatever the
    - * struct seclvl_attribute store function pointer points to. It is
    - * unique for "passwd" and "seclvl".
    - */
    -static ssize_t
    -seclvl_attr_store(struct kobject *kobj,
    - struct attribute *attr, const char *buf, size_t len)
    -{
    - struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj);
    - struct seclvl_attribute *attribute =
    - container_of(attr, struct seclvl_attribute, attr);
    - return attribute->store ? attribute->store(obj, buf, len) : -EIO;
    -}
    -
    -static ssize_t
    -seclvl_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
    -{
    - struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj);
    - struct seclvl_attribute *attribute =
    - container_of(attr, struct seclvl_attribute, attr);
    - return attribute->show ? attribute->show(obj, buf) : -EIO;
    -}
    -
    -/**
    - * Callback function pointers for show and store
    - */
    -static struct sysfs_ops seclvlfs_sysfs_ops = {
    - .show = seclvl_attr_show,
    - .store = seclvl_attr_store,
    -};
    -
    -static struct kobj_type seclvl_ktype = {
    - .sysfs_ops = &seclvlfs_sysfs_ops
    -};
    -
    -decl_subsys(seclvl, &seclvl_ktype, NULL);
    -
    -/**
    * The actual security level. Ranges between -1 and 2 inclusive.
    */
    static int seclvl;
    @@ -213,97 +150,44 @@ static int seclvl_sanity(int reqlvl)
    }

    /**
    - * Called whenever the user reads the sysfs handle to this kernel
    - * object
    - */
    -static ssize_t seclvl_read_file(struct seclvl_obj *obj, char *buff)
    -{
    - return snprintf(buff, PAGE_SIZE, "%d\n", seclvl);
    -}
    -
    -/**
    * security level advancement rules:
    * Valid levels are -1 through 2, inclusive.
    * From -1, stuck. [ in case compiled into kernel ]
    * From 0 or above, can only increment.
    */
    -static int do_seclvl_advance(int newlvl)
    +static void do_seclvl_advance(void *data, u64 val)
    {
    - if (newlvl <= seclvl) {
    - seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
    - "[%d]\n", newlvl);
    - return -EINVAL;
    - }
    + int ret;
    + int newlvl = (int)val;
    +
    + ret = seclvl_sanity(newlvl);
    + if (ret)
    + return;
    +
    if (newlvl > 2) {
    seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
    "[%d]\n", newlvl);
    - return -EINVAL;
    + return;
    }
    if (seclvl == -1) {
    seclvl_printk(1, KERN_WARNING, "Not allowed to advance to "
    "seclvl [%d]\n", seclvl);
    - return -EPERM;
    + return;
    }
    - seclvl = newlvl;
    - return 0;
    + seclvl = newlvl; /* would it be more "correct" to set *data? */
    + return;
    }

    -/**
    - * Called whenever the user writes to the sysfs handle to this kernel
    - * object (seclvl/seclvl). It expects a single-digit number.
    - */
    -static ssize_t
    -seclvl_write_file(struct seclvl_obj *obj, const char *buff, size_t count)
    +static u64 seclvl_int_get(void *data)
    {
    - unsigned long val;
    - if (count > 2 || (count == 2 && buff[1] != '\n')) {
    - seclvl_printk(1, KERN_WARNING, "Invalid value passed to "
    - "seclvl: [%s]\n", buff);
    - return -EINVAL;
    - }
    - val = buff[0] - 48;
    - if (seclvl_sanity(val)) {
    - seclvl_printk(1, KERN_WARNING, "Illegal secure level "
    - "requested: [%d]\n", (int)val);
    - return -EPERM;
    - }
    - if (do_seclvl_advance(val)) {
    - seclvl_printk(0, KERN_ERR, "Failure advancing security level "
    - "to %lu\n", val);
    - }
    - return count;
    + return *(int *)data;
    }

    -/* Generate sysfs_attr_seclvl */
    -static struct seclvl_attribute sysfs_attr_seclvl =
    -__ATTR(seclvl, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_file,
    - seclvl_write_file);
    +DEFINE_SIMPLE_ATTRIBUTE(seclvl_file_ops, seclvl_int_get, do_seclvl_advance, "%d\n");

    static unsigned char hashedPassword[SHA1_DIGEST_SIZE];

    /**
    - * Called whenever the user reads the sysfs passwd handle.
    - */
    -static ssize_t seclvl_read_passwd(struct seclvl_obj *obj, char *buff)
    -{
    - /* So just how good *is* your password? :-) */
    - char tmp[3];
    - int i = 0;
    - buff[0] = '\0';
    - if (hideHash) {
    - /* Security through obscurity */
    - return 0;
    - }
    - while (i < SHA1_DIGEST_SIZE) {
    - snprintf(tmp, 3, "%02x", hashedPassword[i]);
    - strncat(buff, tmp, 2);
    - i++;
    - }
    - strcat(buff, "\n");
    - return ((SHA1_DIGEST_SIZE * 2) + 1);
    -}
    -
    -/**
    * Converts a block of plaintext of into its SHA1 hashed value.
    *
    * It would be nice if crypto had a wrapper to do this for us linear
    @@ -347,12 +231,15 @@ plaintext_to_sha1(unsigned char *hash, c
    * object. It hashes the password and compares the hashed results.
    */
    static ssize_t
    -seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count)
    +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;
    int len;
    +
    if (!*passwd && !*sha1_passwd) {
    seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the "
    "seclvl module, but neither a plain text "
    @@ -363,13 +250,26 @@ seclvl_write_passwd(struct seclvl_obj *o
    "maintainer about this event.\n");
    return -EINVAL;
    }
    - len = strlen(buff);
    +
    + if (count < 0 || count >= PAGE_SIZE)
    + return -ENOMEM;
    + if (*ppos != 0) {
    + return -EINVAL;
    + }
    + page = (char *)get_zeroed_page(GFP_KERNEL);
    + if (!page)
    + return -ENOMEM;
    + len = -EFAULT;
    + if (copy_from_user(page, buf, count))
    + goto out;
    +
    + len = strlen(page);
    /* ``echo "secret" > seclvl/passwd'' includes a newline */
    - if (buff[len - 1] == '\n') {
    + if (page[len - 1] == '\n') {
    len--;
    }
    /* Hash the password, then compare the hashed values */
    - if ((rc = plaintext_to_sha1(tmp, buff, len))) {
    + if ((rc = plaintext_to_sha1(tmp, page, len))) {
    seclvl_printk(0, KERN_ERR, "Error hashing password: rc = "
    "[%d]\n", rc);
    return rc;
    @@ -382,13 +282,16 @@ seclvl_write_passwd(struct seclvl_obj *o
    seclvl_printk(0, KERN_INFO,
    "Password accepted; seclvl reduced to 0.\n");
    seclvl = 0;
    - return count;
    + len = count;
    +
    +out:
    + free_page((unsigned long)page);
    + return len;
    }

    -/* Generate sysfs_attr_passwd */
    -static struct seclvl_attribute sysfs_attr_passwd =
    -__ATTR(passwd, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_passwd,
    - seclvl_write_passwd);
    +static struct file_operations passwd_file_ops = {
    + .write = passwd_write_file,
    +};

    /**
    * Explicitely disallow ptrace'ing the init process.
    @@ -647,22 +550,34 @@ static int processPassword(void)
    }

    /**
    - * Sysfs registrations
    + * securityfs registrations
    */
    -static int doSysfsRegistrations(void)
    +struct dentry *dir_ino, *seclvl_ino, *passwd_ino;
    +
    +static int seclvlfs_register(void)
    {
    - int rc = 0;
    - if ((rc = subsystem_register(&seclvl_subsys))) {
    - seclvl_printk(0, KERN_WARNING,
    - "Error [%d] registering seclvl subsystem\n", rc);
    - return rc;
    - }
    - sysfs_create_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr);
    + dir_ino = securityfs_create_dir("seclvl", NULL);
    + if (!dir_ino)
    + return -EFAULT;
    +
    + seclvl_ino = securityfs_create_file("seclvl", S_IRUGO | S_IWUSR,
    + dir_ino, &seclvl, &seclvl_file_ops);
    + if (!seclvl_ino)
    + goto out_deldir;
    if (*passwd || *sha1_passwd) {
    - sysfs_create_file(&seclvl_subsys.kset.kobj,
    - &sysfs_attr_passwd.attr);
    + passwd_ino = securityfs_create_file("passwd", S_IRUGO | S_IWUSR,
    + dir_ino, NULL, &passwd_file_ops);
    + if (!passwd_ino)
    + goto out_delf;
    }
    return 0;
    +
    +out_deldir:
    + securityfs_remove(dir_ino);
    +out_delf:
    + securityfs_remove(seclvl_ino);
    +
    + return -EFAULT;
    }

    /**
    @@ -677,8 +592,6 @@ static int __init seclvl_init(void)
    rc = -EINVAL;
    goto exit;
    }
    - sysfs_attr_seclvl.attr.owner = THIS_MODULE;
    - sysfs_attr_passwd.attr.owner = THIS_MODULE;
    if (initlvl < -1 || initlvl > 2) {
    seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel "
    "[%d].\n", initlvl);
    @@ -706,7 +619,7 @@ static int __init seclvl_init(void)
    } /* if primary module registered */
    secondary = 1;
    } /* if we registered ourselves with the security framework */
    - if ((rc = doSysfsRegistrations())) {
    + if ((rc = seclvlfs_register())) {
    seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
    goto exit;
    }
    @@ -724,12 +637,11 @@ static int __init seclvl_init(void)
    */
    static void __exit seclvl_exit(void)
    {
    - sysfs_remove_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr);
    + securityfs_remove(seclvl_ino);
    if (*passwd || *sha1_passwd) {
    - sysfs_remove_file(&seclvl_subsys.kset.kobj,
    - &sysfs_attr_passwd.attr);
    + securityfs_remove(passwd_ino);
    }
    - subsystem_unregister(&seclvl_subsys);
    + securityfs_remove(dir_ino);
    if (secondary == 1) {
    mod_unreg_security(MY_NAME, &seclvl_ops);
    } else if (unregister_security(&seclvl_ops)) {
    -
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      Last update: 2005-07-08 00:54    [W:0.097 / U:1.416 seconds]
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