Re: [PATCH] tmpfs: security xattr setting on inode creation

[Sakkinen, Jarkko]

Hi

Noticed some style issues that I need to fix.

On Wed, Feb 22, 2012 at 9:48 AM, Jarkko Sakkinen
<jarkko.sakkinen@xxxxxxxxx> wrote:
> Adds to generic xattr support introduced in Linux 3.0 by
> implementing initxattrs callback. This enables consulting
> of security attributes from LSM and EVM when inode originally
> created.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxx>
> ---
> Âmm/shmem.c | Â 77 +++++++++++++++++++++++++++++++++++++++++++++++------------
> Â1 files changed, 61 insertions(+), 16 deletions(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 7a45ad0..72addf1 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1480,6 +1480,59 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
> Â/*
> Â* File creation. Allocate an inode, and we're done..
> Â*/

Oops. Have to move these new functions before this
comment.

> +
> +static int shmem_xattr_alloc(size_t size, struct shmem_xattr **new_xattr)
> +{
> + Â Â Â /* wrap around? */
> + Â Â Â size_t len = sizeof(**new_xattr) + size;
> + Â Â Â if (len <= sizeof(**new_xattr))
> + Â Â Â Â Â Â Â return -ENOMEM;
> +
> + Â Â Â *new_xattr = kmalloc(len, GFP_KERNEL);
> + Â Â Â if (*new_xattr == NULL)
> + Â Â Â Â Â Â Â return -ENOMEM;
> +
> + Â Â Â (*new_xattr)->size = size;
> + Â Â Â return 0;
> +}
> +
> +static int shmem_initxattrs(struct inode *inode,
> + Â Â Â Â Â Â Â Â Â Â Â Â Â const struct xattr *xattr_array,
> + Â Â Â Â Â Â Â Â Â Â Â Â Â void *fs_info)
> +{
> + Â Â Â const struct xattr *xattr;
> + Â Â Â struct shmem_inode_info *info = SHMEM_I(inode);
> + Â Â Â struct shmem_xattr *new_xattr = NULL;
> + Â Â Â size_t len;
> + Â Â Â int err = 0;
> +
> + Â Â Â for (xattr = xattr_array; xattr->name != NULL; xattr++) {
> + Â Â Â Â Â Â Â err = shmem_xattr_alloc(xattr->value_len, &new_xattr);
> + Â Â Â Â Â Â Â if (err < 0)
> + Â Â Â Â Â Â Â Â Â Â Â break;

Should be "return err;" (consistency).

> +
> + Â Â Â Â Â Â Â len = strlen(xattr->name) + 1;
> + Â Â Â Â Â Â Â new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â GFP_KERNEL);
> + Â Â Â Â Â Â Â if (new_xattr->name == NULL) {
> + Â Â Â Â Â Â Â Â Â Â Â kfree(new_xattr);
> + Â Â Â Â Â Â Â Â Â Â Â return -ENOMEM;
> + Â Â Â Â Â Â Â }
> +
> + Â Â Â Â Â Â Â memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
> + Â Â Â Â Â Â Â Â Â Â ÂXATTR_SECURITY_PREFIX_LEN);
> + Â Â Â Â Â Â Â memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
> + Â Â Â Â Â Â Â Â Â Â Âxattr->name, len);
> + Â Â Â Â Â Â Â memcpy(new_xattr->value, xattr->value, xattr->value_len);
> +
> + Â Â Â Â Â Â Â spin_lock(&info->lock);
> + Â Â Â Â Â Â Â list_add(&new_xattr->list, &info->xattr_list);
> + Â Â Â Â Â Â Â spin_unlock(&info->lock);
> + Â Â Â }
> +
> + Â Â Â return err;

Should be "return 0;" (consistency).

> +}
> +
> Âstatic int
> Âshmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> Â{
> @@ -1490,7 +1543,7 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> Â Â Â Âif (inode) {
> Â Â Â Â Â Â Â Âerror = security_inode_init_security(inode, dir,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â &dentry->d_name,
> - Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ÂNULL, NULL);
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â&shmem_initxattrs, NULL);
> Â Â Â Â Â Â Â Âif (error) {
> Â Â Â Â Â Â Â Â Â Â Â Âif (error != -EOPNOTSUPP) {
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Âiput(inode);
> @@ -1630,7 +1683,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
> Â Â Â Â Â Â Â Âreturn -ENOSPC;
>
> Â Â Â Âerror = security_inode_init_security(inode, dir, &dentry->d_name,
> - Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ÂNULL, NULL);
> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â&shmem_initxattrs, NULL);
> Â Â Â Âif (error) {
> Â Â Â Â Â Â Â Âif (error != -EOPNOTSUPP) {
> Â Â Â Â Â Â Â Â Â Â Â Âiput(inode);
> @@ -1731,26 +1784,19 @@ static int shmem_xattr_get(struct dentry *dentry, const char *name,
> Â Â Â Âreturn ret;
> Â}
>
> -static int shmem_xattr_set(struct dentry *dentry, const char *name,
> +static int shmem_xattr_set(struct inode *inode, const char *name,
> Â Â Â Â Â Â Â Â Â Â Â Â Â const void *value, size_t size, int flags)
> Â{
> - Â Â Â struct inode *inode = dentry->d_inode;
> Â Â Â Âstruct shmem_inode_info *info = SHMEM_I(inode);
> Â Â Â Âstruct shmem_xattr *xattr;
> Â Â Â Âstruct shmem_xattr *new_xattr = NULL;
> - Â Â Â size_t len;
> Â Â Â Âint err = 0;
>
> Â Â Â Â/* value == NULL means remove */
> Â Â Â Âif (value) {
> - Â Â Â Â Â Â Â /* wrap around? */
> - Â Â Â Â Â Â Â len = sizeof(*new_xattr) + size;
> - Â Â Â Â Â Â Â if (len <= sizeof(*new_xattr))
> - Â Â Â Â Â Â Â Â Â Â Â return -ENOMEM;
> -
> - Â Â Â Â Â Â Â new_xattr = kmalloc(len, GFP_KERNEL);
> - Â Â Â Â Â Â Â if (!new_xattr)
> - Â Â Â Â Â Â Â Â Â Â Â return -ENOMEM;
> + Â Â Â Â Â Â Â err = shmem_xattr_alloc(size, &new_xattr);
> + Â Â Â Â Â Â Â if (err < 0)
> + Â Â Â Â Â Â Â Â Â Â Â return err;
>
> Â Â Â Â Â Â Â Ânew_xattr->name = kstrdup(name, GFP_KERNEL);
> Â Â Â Â Â Â Â Âif (!new_xattr->name) {
> @@ -1758,7 +1804,6 @@ static int shmem_xattr_set(struct dentry *dentry, const char *name,
> Â Â Â Â Â Â Â Â Â Â Â Âreturn -ENOMEM;
> Â Â Â Â Â Â Â Â}
>
> - Â Â Â Â Â Â Â new_xattr->size = size;
> Â Â Â Â Â Â Â Âmemcpy(new_xattr->value, value, size);
> Â Â Â Â}
>
> @@ -1858,7 +1903,7 @@ static int shmem_setxattr(struct dentry *dentry, const char *name,
> Â Â Â Âif (size == 0)
> Â Â Â Â Â Â Â Âvalue = ""; Â/* empty EA, do not remove */
>
> - Â Â Â return shmem_xattr_set(dentry, name, value, size, flags);
> + Â Â Â return shmem_xattr_set(dentry->d_inode, name, value, size, flags);
>
> Â}
>
> @@ -1878,7 +1923,7 @@ static int shmem_removexattr(struct dentry *dentry, const char *name)
> Â Â Â Âif (err)
> Â Â Â Â Â Â Â Âreturn err;
>
> - Â Â Â return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
> + Â Â Â return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
> Â}
>
> Âstatic bool xattr_is_trusted(const char *name)
> --
> 1.7.5.4
>

/Jarkko
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