| Message ID | 20231107134012.682009-18-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | security: Move IMA and EVM to the LSM infrastructure | expand |
On 11/7/2023 5:40 AM, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > In preparation for moving IMA and EVM to the LSM infrastructure, introduce > the inode_post_remove_acl hook. > > At inode_remove_acl hook, EVM verifies the file's existing HMAC value. At > inode_post_remove_acl, EVM re-calculates the file's HMAC with the passed > POSIX ACL removed and other file metadata. > > Other LSMs could similarly take some action after successful POSIX ACL > removal. > > The new hook cannot return an error and cannot cause the operation to be > reverted. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> > --- > fs/posix_acl.c | 1 + > include/linux/lsm_hook_defs.h | 2 ++ > include/linux/security.h | 8 ++++++++ > security/security.c | 17 +++++++++++++++++ > 4 files changed, 28 insertions(+) > > diff --git a/fs/posix_acl.c b/fs/posix_acl.c > index 58e3c1e2fbbc..e3fbe1a9f3f5 100644 > --- a/fs/posix_acl.c > +++ b/fs/posix_acl.c > @@ -1246,6 +1246,7 @@ int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, > error = -EIO; > if (!error) { > fsnotify_xattr(dentry); > + security_inode_post_remove_acl(idmap, dentry, acl_name); > evm_inode_post_remove_acl(idmap, dentry, acl_name); > } > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index 6a671616196f..2bf128f7cbae 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -163,6 +163,8 @@ LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name) > LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name) > +LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap, > + struct dentry *dentry, const char *acl_name) > LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry) > LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap, > struct dentry *dentry) > diff --git a/include/linux/security.h b/include/linux/security.h > index d71d0b08e9fe..7cd7126f6545 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -378,6 +378,9 @@ int security_inode_get_acl(struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name); > int security_inode_remove_acl(struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name); > +void security_inode_post_remove_acl(struct mnt_idmap *idmap, > + struct dentry *dentry, > + const char *acl_name); > void security_inode_post_setxattr(struct dentry *dentry, const char *name, > const void *value, size_t size, int flags); > int security_inode_getxattr(struct dentry *dentry, const char *name); > @@ -934,6 +937,11 @@ static inline int security_inode_remove_acl(struct mnt_idmap *idmap, > return 0; > } > > +static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap, > + struct dentry *dentry, > + const char *acl_name) > +{ } > + > static inline void security_inode_post_setxattr(struct dentry *dentry, > const char *name, const void *value, size_t size, int flags) > { } > diff --git a/security/security.c b/security/security.c > index d2dbea54a63a..6eb7c9cff1e5 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2413,6 +2413,23 @@ int security_inode_remove_acl(struct mnt_idmap *idmap, > return evm_inode_remove_acl(idmap, dentry, acl_name); > } > > +/** > + * security_inode_post_remove_acl() - Update inode security after rm posix acls > + * @idmap: idmap of the mount > + * @dentry: file > + * @acl_name: acl name > + * > + * Update inode security data after successfully removing posix acls on > + * @dentry in @idmap. The posix acls are identified by @acl_name. > + */ > +void security_inode_post_remove_acl(struct mnt_idmap *idmap, > + struct dentry *dentry, const char *acl_name) > +{ > + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) > + return; > + call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name); > +} > + > /** > * security_inode_post_setxattr() - Update the inode after a setxattr operation > * @dentry: file
On Nov 7, 2023 Roberto Sassu <roberto.sassu@huaweicloud.com> wrote: > > In preparation for moving IMA and EVM to the LSM infrastructure, introduce > the inode_post_remove_acl hook. > > At inode_remove_acl hook, EVM verifies the file's existing HMAC value. At > inode_post_remove_acl, EVM re-calculates the file's HMAC with the passed > POSIX ACL removed and other file metadata. > > Other LSMs could similarly take some action after successful POSIX ACL > removal. > > The new hook cannot return an error and cannot cause the operation to be > reverted. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> > Acked-by: Casey Schaufler <casey@schaufler-ca.com> > Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> > --- > fs/posix_acl.c | 1 + > include/linux/lsm_hook_defs.h | 2 ++ > include/linux/security.h | 8 ++++++++ > security/security.c | 17 +++++++++++++++++ > 4 files changed, 28 insertions(+) ... > diff --git a/security/security.c b/security/security.c > index d2dbea54a63a..6eb7c9cff1e5 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2413,6 +2413,23 @@ int security_inode_remove_acl(struct mnt_idmap *idmap, > return evm_inode_remove_acl(idmap, dentry, acl_name); > } > > +/** > + * security_inode_post_remove_acl() - Update inode security after rm posix acls > + * @idmap: idmap of the mount > + * @dentry: file > + * @acl_name: acl name > + * > + * Update inode security data after successfully removing posix acls on > + * @dentry in @idmap. The posix acls are identified by @acl_name. > + */ > +void security_inode_post_remove_acl(struct mnt_idmap *idmap, > + struct dentry *dentry, const char *acl_name) > +{ > + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) > + return; See previous comments regaring S_PRIVATE checks. > + call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name); > +} > + > /** > * security_inode_post_setxattr() - Update the inode after a setxattr operation > * @dentry: file > -- > 2.34.1 -- paul-moore.com
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 58e3c1e2fbbc..e3fbe1a9f3f5 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1246,6 +1246,7 @@ int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, error = -EIO; if (!error) { fsnotify_xattr(dentry); + security_inode_post_remove_acl(idmap, dentry, acl_name); evm_inode_post_remove_acl(idmap, dentry, acl_name); } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 6a671616196f..2bf128f7cbae 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -163,6 +163,8 @@ LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) +LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap, + struct dentry *dentry, const char *acl_name) LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry) LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap, struct dentry *dentry) diff --git a/include/linux/security.h b/include/linux/security.h index d71d0b08e9fe..7cd7126f6545 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -378,6 +378,9 @@ int security_inode_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name); int security_inode_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name); +void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, + const char *acl_name); void security_inode_post_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags); int security_inode_getxattr(struct dentry *dentry, const char *name); @@ -934,6 +937,11 @@ static inline int security_inode_remove_acl(struct mnt_idmap *idmap, return 0; } +static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, + const char *acl_name) +{ } + static inline void security_inode_post_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { } diff --git a/security/security.c b/security/security.c index d2dbea54a63a..6eb7c9cff1e5 100644 --- a/security/security.c +++ b/security/security.c @@ -2413,6 +2413,23 @@ int security_inode_remove_acl(struct mnt_idmap *idmap, return evm_inode_remove_acl(idmap, dentry, acl_name); } +/** + * security_inode_post_remove_acl() - Update inode security after rm posix acls + * @idmap: idmap of the mount + * @dentry: file + * @acl_name: acl name + * + * Update inode security data after successfully removing posix acls on + * @dentry in @idmap. The posix acls are identified by @acl_name. + */ +void security_inode_post_remove_acl(struct mnt_idmap *idmap, + struct dentry *dentry, const char *acl_name) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name); +} + /** * security_inode_post_setxattr() - Update the inode after a setxattr operation * @dentry: file