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 <[email protected]>
---
mm/shmem.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++------------
1 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)
/*
* File creation. Allocate an inode, and we're done..
*/
+
+static int shmem_xattr_alloc(size_t size, struct shmem_xattr **new_xattr)
+{
+ /* wrap around? */
+ size_t len = sizeof(**new_xattr) + size;
+ if (len <= sizeof(**new_xattr))
+ return -ENOMEM;
+
+ *new_xattr = kmalloc(len, GFP_KERNEL);
+ if (*new_xattr == NULL)
+ return -ENOMEM;
+
+ (*new_xattr)->size = size;
+ return 0;
+}
+
+static int shmem_initxattrs(struct inode *inode,
+ const struct xattr *xattr_array,
+ void *fs_info)
+{
+ const struct xattr *xattr;
+ struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_xattr *new_xattr = NULL;
+ size_t len;
+ int err = 0;
+
+ for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+ err = shmem_xattr_alloc(xattr->value_len, &new_xattr);
+ if (err < 0)
+ break;
+
+ len = strlen(xattr->name) + 1;
+ new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
+ GFP_KERNEL);
+ if (new_xattr->name == NULL) {
+ kfree(new_xattr);
+ return -ENOMEM;
+ }
+
+ memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN);
+ memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
+ xattr->name, len);
+ memcpy(new_xattr->value, xattr->value, xattr->value_len);
+
+ spin_lock(&info->lock);
+ list_add(&new_xattr->list, &info->xattr_list);
+ spin_unlock(&info->lock);
+ }
+
+ return err;
+}
+
static int
shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
{
@@ -1490,7 +1543,7 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
if (inode) {
error = security_inode_init_security(inode, dir,
&dentry->d_name,
- NULL, NULL);
+ &shmem_initxattrs, NULL);
if (error) {
if (error != -EOPNOTSUPP) {
iput(inode);
@@ -1630,7 +1683,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
return -ENOSPC;
error = security_inode_init_security(inode, dir, &dentry->d_name,
- NULL, NULL);
+ &shmem_initxattrs, NULL);
if (error) {
if (error != -EOPNOTSUPP) {
iput(inode);
@@ -1731,26 +1784,19 @@ static int shmem_xattr_get(struct dentry *dentry, const char *name,
return ret;
}
-static int shmem_xattr_set(struct dentry *dentry, const char *name,
+static int shmem_xattr_set(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
- struct inode *inode = dentry->d_inode;
struct shmem_inode_info *info = SHMEM_I(inode);
struct shmem_xattr *xattr;
struct shmem_xattr *new_xattr = NULL;
- size_t len;
int err = 0;
/* value == NULL means remove */
if (value) {
- /* wrap around? */
- len = sizeof(*new_xattr) + size;
- if (len <= sizeof(*new_xattr))
- return -ENOMEM;
-
- new_xattr = kmalloc(len, GFP_KERNEL);
- if (!new_xattr)
- return -ENOMEM;
+ err = shmem_xattr_alloc(size, &new_xattr);
+ if (err < 0)
+ return err;
new_xattr->name = kstrdup(name, GFP_KERNEL);
if (!new_xattr->name) {
@@ -1758,7 +1804,6 @@ static int shmem_xattr_set(struct dentry *dentry, const char *name,
return -ENOMEM;
}
- new_xattr->size = size;
memcpy(new_xattr->value, value, size);
}
@@ -1858,7 +1903,7 @@ static int shmem_setxattr(struct dentry *dentry, const char *name,
if (size == 0)
value = ""; /* empty EA, do not remove */
- return shmem_xattr_set(dentry, name, value, size, flags);
+ return shmem_xattr_set(dentry->d_inode, name, value, size, flags);
}
@@ -1878,7 +1923,7 @@ static int shmem_removexattr(struct dentry *dentry, const char *name)
if (err)
return err;
- return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
+ return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
}
static bool xattr_is_trusted(const char *name)
--
1.7.5.4
Hi
Noticed some style issues that I need to fix.
On Wed, Feb 22, 2012 at 9:48 AM, Jarkko Sakkinen
<[email protected]> 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 <[email protected]>
> ---
> mm/shmem.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++------------
> 1 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)
> /*
> * File creation. Allocate an inode, and we're done..
> */
Oops. Have to move these new functions before this
comment.
> +
> +static int shmem_xattr_alloc(size_t size, struct shmem_xattr **new_xattr)
> +{
> + /* wrap around? */
> + size_t len = sizeof(**new_xattr) + size;
> + if (len <= sizeof(**new_xattr))
> + return -ENOMEM;
> +
> + *new_xattr = kmalloc(len, GFP_KERNEL);
> + if (*new_xattr == NULL)
> + return -ENOMEM;
> +
> + (*new_xattr)->size = size;
> + return 0;
> +}
> +
> +static int shmem_initxattrs(struct inode *inode,
> + const struct xattr *xattr_array,
> + void *fs_info)
> +{
> + const struct xattr *xattr;
> + struct shmem_inode_info *info = SHMEM_I(inode);
> + struct shmem_xattr *new_xattr = NULL;
> + size_t len;
> + int err = 0;
> +
> + for (xattr = xattr_array; xattr->name != NULL; xattr++) {
> + err = shmem_xattr_alloc(xattr->value_len, &new_xattr);
> + if (err < 0)
> + break;
Should be "return err;" (consistency).
> +
> + len = strlen(xattr->name) + 1;
> + new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
> + GFP_KERNEL);
> + if (new_xattr->name == NULL) {
> + kfree(new_xattr);
> + return -ENOMEM;
> + }
> +
> + memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
> + XATTR_SECURITY_PREFIX_LEN);
> + memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
> + xattr->name, len);
> + memcpy(new_xattr->value, xattr->value, xattr->value_len);
> +
> + spin_lock(&info->lock);
> + list_add(&new_xattr->list, &info->xattr_list);
> + spin_unlock(&info->lock);
> + }
> +
> + return err;
Should be "return 0;" (consistency).
> +}
> +
> static int
> shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> {
> @@ -1490,7 +1543,7 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
> if (inode) {
> error = security_inode_init_security(inode, dir,
> &dentry->d_name,
> - NULL, NULL);
> + &shmem_initxattrs, NULL);
> if (error) {
> if (error != -EOPNOTSUPP) {
> iput(inode);
> @@ -1630,7 +1683,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
> return -ENOSPC;
>
> error = security_inode_init_security(inode, dir, &dentry->d_name,
> - NULL, NULL);
> + &shmem_initxattrs, NULL);
> if (error) {
> if (error != -EOPNOTSUPP) {
> iput(inode);
> @@ -1731,26 +1784,19 @@ static int shmem_xattr_get(struct dentry *dentry, const char *name,
> return ret;
> }
>
> -static int shmem_xattr_set(struct dentry *dentry, const char *name,
> +static int shmem_xattr_set(struct inode *inode, const char *name,
> const void *value, size_t size, int flags)
> {
> - struct inode *inode = dentry->d_inode;
> struct shmem_inode_info *info = SHMEM_I(inode);
> struct shmem_xattr *xattr;
> struct shmem_xattr *new_xattr = NULL;
> - size_t len;
> int err = 0;
>
> /* value == NULL means remove */
> if (value) {
> - /* wrap around? */
> - len = sizeof(*new_xattr) + size;
> - if (len <= sizeof(*new_xattr))
> - return -ENOMEM;
> -
> - new_xattr = kmalloc(len, GFP_KERNEL);
> - if (!new_xattr)
> - return -ENOMEM;
> + err = shmem_xattr_alloc(size, &new_xattr);
> + if (err < 0)
> + return err;
>
> new_xattr->name = kstrdup(name, GFP_KERNEL);
> if (!new_xattr->name) {
> @@ -1758,7 +1804,6 @@ static int shmem_xattr_set(struct dentry *dentry, const char *name,
> return -ENOMEM;
> }
>
> - new_xattr->size = size;
> memcpy(new_xattr->value, value, size);
> }
>
> @@ -1858,7 +1903,7 @@ static int shmem_setxattr(struct dentry *dentry, const char *name,
> if (size == 0)
> value = ""; /* empty EA, do not remove */
>
> - return shmem_xattr_set(dentry, name, value, size, flags);
> + return shmem_xattr_set(dentry->d_inode, name, value, size, flags);
>
> }
>
> @@ -1878,7 +1923,7 @@ static int shmem_removexattr(struct dentry *dentry, const char *name)
> if (err)
> return err;
>
> - return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE);
> + return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
> }
>
> static bool xattr_is_trusted(const char *name)
> --
> 1.7.5.4
>
/Jarkko
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