Provide two new security hooks for use with security files that are used when a file is copied up between layers: (1) security_inode_copy_up(). This is called so that the security label on the destination file can be set appropriately. (2) security_inode_copy_up_xattr(). This is called so that each xattr being copied up can be vetted - including modification and discard. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> --- include/linux/security.h | 35 +++++++++++++++++++++++++++++++++++ security/capability.c | 13 +++++++++++++ security/security.c | 13 +++++++++++++ 3 files changed, 61 insertions(+) diff --git a/include/linux/security.h b/include/linux/security.h index ba96471c11ba..637a24c75d46 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -562,6 +562,24 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @inode contains a pointer to the inode. * @secid contains a pointer to the location where result will be saved. * In case of failure, @secid will be set to zero. + * @inode_copy_up: + * Generate the secid associated with the destination inode when a unioned + * file is copied up from a lower layer to the union/overlay layer. + * @src indicates the file that is being copied up. + * @dst indicates the file that has being created by the copy up. + * Returns 0 on success or a negative error code on error. + * @inode_copy_up_xattr: + * Filter/modify the xattrs being copied up when a unioned file is copied + * up from a lower layer to the union/overlay layer. + * @src indicates the file that is being copied up. + * @dst indicates the file that has being created by the copy up. + * @name indicates the name of the xattr. + * @value, *@size indicate the payload of the xattr. + * Returns 0 to accept the xattr, 1 to discard the xattr or a negative + * error code to abort the copy up. The xattr buffer must be at least + * XATTR_SIZE_MAX in capacity and the contents may be modified and *@size + * changed appropriately. + * * * Security hooks for file operations * @@ -1543,6 +1561,9 @@ struct security_operations { int (*inode_setsecurity) (struct inode *inode, const char *name, const void *value, size_t size, int flags); int (*inode_listsecurity) (struct inode *inode, char *buffer, size_t buffer_size); void (*inode_getsecid) (const struct inode *inode, u32 *secid); + int (*inode_copy_up) (struct dentry *src, struct dentry *dst); + int (*inode_copy_up_xattr) (struct dentry *src, struct dentry *dst, + const char *name, void *value, size_t *size); int (*file_permission) (struct file *file, int mask); int (*file_alloc_security) (struct file *file); @@ -1823,6 +1844,10 @@ int security_inode_getsecurity(const struct inode *inode, const char *name, void int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags); int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size); void security_inode_getsecid(const struct inode *inode, u32 *secid); +int security_inode_copy_up(struct dentry *src, struct dentry *dst); +int security_inode_copy_up_xattr(struct dentry *src, struct dentry *dst, + const char *name, void *value, size_t *size); + int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); void security_file_free(struct file *file); @@ -2264,6 +2289,16 @@ static inline void security_inode_getsecid(const struct inode *inode, u32 *secid *secid = 0; } +static inline int security_inode_copy_up(struct dentry *src, struct dentry *dst) +{ + return 0; +} +static inline int security_inode_copy_up_xattr(struct dentry *src, struct dentry *dst, + const char *name, const void *value, size_t size) +{ + return 0; +} + static inline int security_file_permission(struct file *file, int mask) { return 0; diff --git a/security/capability.c b/security/capability.c index d68c57a62bcf..6b21615d1500 100644 --- a/security/capability.c +++ b/security/capability.c @@ -245,6 +245,17 @@ static void cap_inode_getsecid(const struct inode *inode, u32 *secid) *secid = 0; } +static int cap_inode_copy_up(struct dentry *src, struct dentry *dst) +{ + return 0; +} + +static int cap_inode_copy_up_xattr(struct dentry *src, struct dentry *dst, + const char *name, void *value, size_t *size) +{ + return 0; +} + #ifdef CONFIG_SECURITY_PATH static int cap_path_mknod(struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev) @@ -986,6 +997,8 @@ void __init security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, inode_setsecurity); set_to_cap_if_null(ops, inode_listsecurity); set_to_cap_if_null(ops, inode_getsecid); + set_to_cap_if_null(ops, inode_copy_up); + set_to_cap_if_null(ops, inode_copy_up_xattr); #ifdef CONFIG_SECURITY_PATH set_to_cap_if_null(ops, path_mknod); set_to_cap_if_null(ops, path_mkdir); diff --git a/security/security.c b/security/security.c index 18b35c63fc0c..96e2f189ff1e 100644 --- a/security/security.c +++ b/security/security.c @@ -683,6 +683,19 @@ void security_inode_getsecid(const struct inode *inode, u32 *secid) security_ops->inode_getsecid(inode, secid); } +int security_inode_copy_up(struct dentry *src, struct dentry *dst) +{ + return security_ops->inode_copy_up(src, dst); +} +EXPORT_SYMBOL(security_inode_copy_up); + +int security_inode_copy_up_xattr(struct dentry *src, struct dentry *dst, + const char *name, void *value, size_t *size) +{ + return security_ops->inode_copy_up_xattr(src, dst, name, value, size); +} +EXPORT_SYMBOL(security_inode_copy_up_xattr); + int security_file_permission(struct file *file, int mask) { int ret; -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html