| Message ID | 20230904133415.1799503-19-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | security: Move IMA and EVM to the LSM infrastructure | expand |
On 9/4/23 09:34, 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_set_acl hook. > > It is useful for EVM to recalculate the HMAC on the modified POSIX ACL and > other file metadata, after it verified the HMAC of current file metadata > with the inode_set_acl hook. > > LSMs should use the new hook instead of inode_set_acl, when they need to > know that the operation was done successfully (not known in inode_set_acl). > The new hook cannot return an error and cannot cause the operation to be > reverted. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > fs/posix_acl.c | 1 + > include/linux/lsm_hook_defs.h | 2 ++ > include/linux/security.h | 7 +++++++ > security/security.c | 17 +++++++++++++++++ > 4 files changed, 27 insertions(+) > > diff --git a/fs/posix_acl.c b/fs/posix_acl.c > index 7fa1b738bbab..3b7dbea5c3ff 100644 > --- a/fs/posix_acl.c > +++ b/fs/posix_acl.c > @@ -1137,6 +1137,7 @@ int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, > error = -EIO; > if (!error) { > fsnotify_xattr(dentry); > + security_inode_post_set_acl(dentry, acl_name, kacl); > evm_inode_post_set_acl(dentry, acl_name, kacl); > } > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index 9ae573b83737..bba1fbd97207 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -157,6 +157,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, > const char *name) > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) > +LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry, > + const char *acl_name, struct posix_acl *kacl) > 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, > diff --git a/include/linux/security.h b/include/linux/security.h > index 5f296761883f..556d019ebe5c 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -367,6 +367,8 @@ int security_inode_setxattr(struct mnt_idmap *idmap, > int security_inode_set_acl(struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name, > struct posix_acl *kacl); > +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, > + struct posix_acl *kacl); > 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, > @@ -894,6 +896,11 @@ static inline int security_inode_set_acl(struct mnt_idmap *idmap, > return 0; > } > > +static inline void security_inode_post_set_acl(struct dentry *dentry, > + const char *acl_name, > + struct posix_acl *kacl) > +{ } > + > static inline int security_inode_get_acl(struct mnt_idmap *idmap, > struct dentry *dentry, > const char *acl_name) > diff --git a/security/security.c b/security/security.c > index aa6274c90147..aabace9e24d9 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2260,6 +2260,23 @@ int security_inode_set_acl(struct mnt_idmap *idmap, > return evm_inode_set_acl(idmap, dentry, acl_name, kacl); > } > > +/** > + * security_inode_post_set_acl() - Update inode security after set_acl() > + * @dentry: file > + * @acl_name: acl name > + * @kacl: acl struct > + * > + * Update inode security field after successful set_acl operation on @dentry. > + * The posix acls in @kacl are identified by @acl_name. > + */ > +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, > + struct posix_acl *kacl) > +{ > + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) > + return; > + call_void_hook(inode_post_set_acl, dentry, acl_name, kacl); > +} > + > /** > * security_inode_get_acl() - Check if reading posix acls is allowed > * @idmap: idmap of the mount Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
On Mon, 2023-09-04 at 15:34 +0200, 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_set_acl hook. > > It is useful for EVM to recalculate the HMAC on the modified POSIX ACL and > other file metadata, after it verified the HMAC of current file metadata > with the inode_set_acl hook. Please reword this and the inode_post_remove_acl patch similar to my comments on "[PATCH v3 12/25] security: Introduce inode_post_setattr hook]".
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 7fa1b738bbab..3b7dbea5c3ff 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -1137,6 +1137,7 @@ int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, error = -EIO; if (!error) { fsnotify_xattr(dentry); + security_inode_post_set_acl(dentry, acl_name, kacl); evm_inode_post_set_acl(dentry, acl_name, kacl); } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 9ae573b83737..bba1fbd97207 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -157,6 +157,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, const char *name) LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) +LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) 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, diff --git a/include/linux/security.h b/include/linux/security.h index 5f296761883f..556d019ebe5c 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -367,6 +367,8 @@ int security_inode_setxattr(struct mnt_idmap *idmap, int security_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl); +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, + struct posix_acl *kacl); 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, @@ -894,6 +896,11 @@ static inline int security_inode_set_acl(struct mnt_idmap *idmap, return 0; } +static inline void security_inode_post_set_acl(struct dentry *dentry, + const char *acl_name, + struct posix_acl *kacl) +{ } + static inline int security_inode_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) diff --git a/security/security.c b/security/security.c index aa6274c90147..aabace9e24d9 100644 --- a/security/security.c +++ b/security/security.c @@ -2260,6 +2260,23 @@ int security_inode_set_acl(struct mnt_idmap *idmap, return evm_inode_set_acl(idmap, dentry, acl_name, kacl); } +/** + * security_inode_post_set_acl() - Update inode security after set_acl() + * @dentry: file + * @acl_name: acl name + * @kacl: acl struct + * + * Update inode security field after successful set_acl operation on @dentry. + * The posix acls in @kacl are identified by @acl_name. + */ +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, + struct posix_acl *kacl) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_set_acl, dentry, acl_name, kacl); +} + /** * security_inode_get_acl() - Check if reading posix acls is allowed * @idmap: idmap of the mount