| Message ID | 20211216054323.1707384-15-stefanb@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ima: Namespace IMA with audit support in IMA-ns | expand |
On Thu, Dec 16, 2021 at 12:43:23AM -0500, Stefan Berger wrote: > From: Stefan Berger <stefanb@linux.ibm.com> > > Setup securityfs with symlinks, directories, and files for IMA > namespacing support. The same directory structure that IMA uses on the > host is also created for the namespacing case. > > The securityfs file and directory ownerships cannot be set when the > IMA namespace is initialized. Therefore, delay the setup of the file > system to a later point when securityfs is in securityfs_fill_super. > > This filesystem can now be mounted as follows: > > mount -t securityfs /sys/kernel/security/ /sys/kernel/security/ > > The following directories, symlinks, and files are then available. > > $ ls -l sys/kernel/security/ > total 0 > lr--r--r--. 1 root root 0 Dec 2 00:18 ima -> integrity/ima > drwxr-xr-x. 3 root root 0 Dec 2 00:18 integrity > > $ ls -l sys/kernel/security/ima/ > total 0 > -r--r-----. 1 root root 0 Dec 2 00:18 ascii_runtime_measurements > -r--r-----. 1 root root 0 Dec 2 00:18 binary_runtime_measurements > -rw-------. 1 root root 0 Dec 2 00:18 policy > -r--r-----. 1 root root 0 Dec 2 00:18 runtime_measurements_count > -r--r-----. 1 root root 0 Dec 2 00:18 violations > > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> > --- > include/linux/ima.h | 14 ++++++++++++ > security/inode.c | 6 ++++- > security/integrity/ima/ima.h | 1 + > security/integrity/ima/ima_fs.c | 40 ++++++++++++++++++++++++--------- > 4 files changed, 49 insertions(+), 12 deletions(-) > > diff --git a/include/linux/ima.h b/include/linux/ima.h > index f9e592bb9560..a2705aa5242a 100644 > --- a/include/linux/ima.h > +++ b/include/linux/ima.h > @@ -40,6 +40,7 @@ extern int ima_measure_critical_data(const char *event_label, > const char *event_name, > const void *buf, size_t buf_len, > bool hash, u8 *digest, size_t digest_len); > +extern int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root); > > #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM > extern void ima_appraise_parse_cmdline(void); > @@ -232,6 +233,12 @@ static inline struct ima_namespace *get_current_ns(void) > return current_user_ns()->ima_ns; > } > > +static inline int ima_securityfs_init(struct user_namespace *user_ns, > + struct dentry *root) > +{ > + return ima_fs_ns_init(user_ns, root); > +} > + > #else > > static inline void free_ima_ns(struct user_namespace *user_ns) > @@ -250,6 +257,13 @@ static inline struct ima_namespace *get_current_ns(void) > { > return &init_ima_ns; > } > + > +static inline int ima_securityfs_init(struct user_namespace *ns, > + struct dentry *root) > +{ > + return 0; > +} > + > #endif /* CONFIG_IMA_NS */ > > #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING) > diff --git a/security/inode.c b/security/inode.c > index a0d9f086e3d5..ad9395d121f2 100644 > --- a/security/inode.c > +++ b/security/inode.c > @@ -16,6 +16,7 @@ > #include <linux/fs_context.h> > #include <linux/mount.h> > #include <linux/pagemap.h> > +#include <linux/ima.h> > #include <linux/init.h> > #include <linux/namei.h> > #include <linux/security.h> > @@ -77,7 +78,10 @@ static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc) > sb->s_op = &securityfs_super_operations; > sb->s_root->d_inode->i_op = &securityfs_dir_inode_operations; > > - return 0; > + if (ns != &init_user_ns) > + error = ima_securityfs_init(ns, sb->s_root); > + > + return error; > } > > static int securityfs_get_tree(struct fs_context *fc) > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index d51703290e25..9b0f6a3763f9 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -148,6 +148,7 @@ struct ima_namespace { > int valid_policy; > > struct dentry *policy_dentry; > + bool policy_dentry_removed; > } __randomize_layout; > > extern const int read_idmap[]; > diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c > index 7c5a721f4f3d..3b8001ba62e3 100644 > --- a/security/integrity/ima/ima_fs.c > +++ b/security/integrity/ima/ima_fs.c > @@ -431,6 +431,7 @@ static int ima_release_policy(struct inode *inode, struct file *file) > #if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) > securityfs_remove(ns->policy_dentry); > ns->policy_dentry = NULL; > + ns->policy_dentry_removed = true; > #elif defined(CONFIG_IMA_WRITE_POLICY) > clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags); > #elif defined(CONFIG_IMA_READ_POLICY) > @@ -447,21 +448,31 @@ static const struct file_operations ima_measure_policy_ops = { > .llseek = generic_file_llseek, > }; > > -static int __init ima_fs_ns_init(struct user_namespace *user_ns) > +int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root) > { > struct ima_namespace *ns = user_ns->ima_ns; > - struct dentry *ima_dir; > + struct dentry *int_dir; > + struct dentry *ima_dir = NULL; > struct dentry *ima_symlink = NULL; > struct dentry *binary_runtime_measurements = NULL; > struct dentry *ascii_runtime_measurements = NULL; > struct dentry *runtime_measurements_count = NULL; > struct dentry *violations = NULL; > > - ima_dir = securityfs_create_dir("ima", integrity_dir); > + /* FIXME: update when evm and integrity are namespaced */ > + if (user_ns != &init_user_ns) { > + int_dir = > + securityfs_create_dir("integrity", root); > + if (IS_ERR(int_dir)) > + return -1; That should probably be return PTR_ERR(int_dir)
On 12/16/21 08:51, Christian Brauner wrote: > >> +int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root) >> { >> struct ima_namespace *ns = user_ns->ima_ns; >> - struct dentry *ima_dir; >> + struct dentry *int_dir; >> + struct dentry *ima_dir = NULL; >> struct dentry *ima_symlink = NULL; >> struct dentry *binary_runtime_measurements = NULL; >> struct dentry *ascii_runtime_measurements = NULL; >> struct dentry *runtime_measurements_count = NULL; >> struct dentry *violations = NULL; >> >> - ima_dir = securityfs_create_dir("ima", integrity_dir); >> + /* FIXME: update when evm and integrity are namespaced */ >> + if (user_ns != &init_user_ns) { >> + int_dir = >> + securityfs_create_dir("integrity", root); >> + if (IS_ERR(int_dir)) >> + return -1; > That should probably be return PTR_ERR(int_dir) That's actually from current usptream ( https://elixir.bootlin.com/linux/latest/source/security/integrity/ima/ima_fs.c#L457 ) The question is then whether at the end it should also return something else than what it currently returns: out: securityfs_remove(violations); [...] securityfs_remove(ima_policy); return -1;
diff --git a/include/linux/ima.h b/include/linux/ima.h index f9e592bb9560..a2705aa5242a 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -40,6 +40,7 @@ extern int ima_measure_critical_data(const char *event_label, const char *event_name, const void *buf, size_t buf_len, bool hash, u8 *digest, size_t digest_len); +extern int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root); #ifdef CONFIG_IMA_APPRAISE_BOOTPARAM extern void ima_appraise_parse_cmdline(void); @@ -232,6 +233,12 @@ static inline struct ima_namespace *get_current_ns(void) return current_user_ns()->ima_ns; } +static inline int ima_securityfs_init(struct user_namespace *user_ns, + struct dentry *root) +{ + return ima_fs_ns_init(user_ns, root); +} + #else static inline void free_ima_ns(struct user_namespace *user_ns) @@ -250,6 +257,13 @@ static inline struct ima_namespace *get_current_ns(void) { return &init_ima_ns; } + +static inline int ima_securityfs_init(struct user_namespace *ns, + struct dentry *root) +{ + return 0; +} + #endif /* CONFIG_IMA_NS */ #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING) diff --git a/security/inode.c b/security/inode.c index a0d9f086e3d5..ad9395d121f2 100644 --- a/security/inode.c +++ b/security/inode.c @@ -16,6 +16,7 @@ #include <linux/fs_context.h> #include <linux/mount.h> #include <linux/pagemap.h> +#include <linux/ima.h> #include <linux/init.h> #include <linux/namei.h> #include <linux/security.h> @@ -77,7 +78,10 @@ static int securityfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_op = &securityfs_super_operations; sb->s_root->d_inode->i_op = &securityfs_dir_inode_operations; - return 0; + if (ns != &init_user_ns) + error = ima_securityfs_init(ns, sb->s_root); + + return error; } static int securityfs_get_tree(struct fs_context *fc) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index d51703290e25..9b0f6a3763f9 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -148,6 +148,7 @@ struct ima_namespace { int valid_policy; struct dentry *policy_dentry; + bool policy_dentry_removed; } __randomize_layout; extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 7c5a721f4f3d..3b8001ba62e3 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -431,6 +431,7 @@ static int ima_release_policy(struct inode *inode, struct file *file) #if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY) securityfs_remove(ns->policy_dentry); ns->policy_dentry = NULL; + ns->policy_dentry_removed = true; #elif defined(CONFIG_IMA_WRITE_POLICY) clear_bit(IMA_FS_BUSY, &ns->ima_fs_flags); #elif defined(CONFIG_IMA_READ_POLICY) @@ -447,21 +448,31 @@ static const struct file_operations ima_measure_policy_ops = { .llseek = generic_file_llseek, }; -static int __init ima_fs_ns_init(struct user_namespace *user_ns) +int ima_fs_ns_init(struct user_namespace *user_ns, struct dentry *root) { struct ima_namespace *ns = user_ns->ima_ns; - struct dentry *ima_dir; + struct dentry *int_dir; + struct dentry *ima_dir = NULL; struct dentry *ima_symlink = NULL; struct dentry *binary_runtime_measurements = NULL; struct dentry *ascii_runtime_measurements = NULL; struct dentry *runtime_measurements_count = NULL; struct dentry *violations = NULL; - ima_dir = securityfs_create_dir("ima", integrity_dir); + /* FIXME: update when evm and integrity are namespaced */ + if (user_ns != &init_user_ns) { + int_dir = + securityfs_create_dir("integrity", root); + if (IS_ERR(int_dir)) + return -1; + } else + int_dir = integrity_dir; + + ima_dir = securityfs_create_dir("ima", int_dir); if (IS_ERR(ima_dir)) - return -1; + goto out; - ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima", + ima_symlink = securityfs_create_symlink("ima", root, "integrity/ima", NULL); if (IS_ERR(ima_symlink)) goto out; @@ -493,11 +504,15 @@ static int __init ima_fs_ns_init(struct user_namespace *user_ns) if (IS_ERR(violations)) goto out; - ns->policy_dentry = securityfs_create_file("policy", POLICY_FILE_FLAGS, - ima_dir, NULL, - &ima_measure_policy_ops); - if (IS_ERR(ns->policy_dentry)) - goto out; + + if (!ns->policy_dentry_removed) { + ns->policy_dentry = + securityfs_create_file("policy", POLICY_FILE_FLAGS, + ima_dir, NULL, + &ima_measure_policy_ops); + if (IS_ERR(ns->policy_dentry)) + goto out; + } return 0; out: @@ -508,10 +523,13 @@ static int __init ima_fs_ns_init(struct user_namespace *user_ns) securityfs_remove(binary_runtime_measurements); securityfs_remove(ima_symlink); securityfs_remove(ima_dir); + if (user_ns != &init_user_ns) + securityfs_remove(integrity_dir); + return -1; } int __init ima_fs_init(void) { - return ima_fs_ns_init(&init_user_ns); + return ima_fs_ns_init(&init_user_ns, NULL); }