| Message ID | 20230303181842.1087717-16-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | security: Move IMA and EVM to the LSM infrastructure | expand |
On 3/3/23 13:18, 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_removexattr hook. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Hi Roberto, On Fri, 2023-03-03 at 19:18 +0100, 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_removexattr hook. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > fs/xattr.c | 1 + > include/linux/lsm_hook_defs.h | 2 ++ > include/linux/security.h | 5 +++++ > security/security.c | 14 ++++++++++++++ > 4 files changed, 22 insertions(+) > > diff --git a/fs/xattr.c b/fs/xattr.c > index 14a7eb3c8fa..10c959d9fc6 100644 > --- a/fs/xattr.c > +++ b/fs/xattr.c > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, > > if (!error) { > fsnotify_xattr(dentry); > + security_inode_post_removexattr(dentry, name); > evm_inode_post_removexattr(dentry, name); > } Nothing wrong with this, but other places in this function test "if (error) goto ...". Perhaps it is time to clean this up. > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index eedefbcdde3..2ae5224d967 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, > struct dentry *dentry, const char *name) > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, > + const char *name) @Christian should the security_inode_removexattr() and security_inode_post_removexattr() arguments be the same? > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) > LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote: > Hi Roberto, > > On Fri, 2023-03-03 at 19:18 +0100, 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_removexattr hook. > > > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > --- > > fs/xattr.c | 1 + > > include/linux/lsm_hook_defs.h | 2 ++ > > include/linux/security.h | 5 +++++ > > security/security.c | 14 ++++++++++++++ > > 4 files changed, 22 insertions(+) > > > > diff --git a/fs/xattr.c b/fs/xattr.c > > index 14a7eb3c8fa..10c959d9fc6 100644 > > --- a/fs/xattr.c > > +++ b/fs/xattr.c > > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, > > > > if (!error) { > > fsnotify_xattr(dentry); > > + security_inode_post_removexattr(dentry, name); > > evm_inode_post_removexattr(dentry, name); > > } > > Nothing wrong with this, but other places in this function test "if > (error) goto ...". Perhaps it is time to clean this up. Theoretically, all 'goto out' can be replaced with 'return error'. I would be more in favor of minimizing the changes as much as possible to reach the main goal. But it is ok also to change the last part. Thanks Roberto > > > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > > index eedefbcdde3..2ae5224d967 100644 > > --- a/include/linux/lsm_hook_defs.h > > +++ b/include/linux/lsm_hook_defs.h > > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) > > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) > > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, > > struct dentry *dentry, const char *name) > > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, > > + const char *name) > > @Christian should the security_inode_removexattr() and > security_inode_post_removexattr() arguments be the same? > > > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, > > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) > > LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote: > Hi Roberto, > > On Fri, 2023-03-03 at 19:18 +0100, 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_removexattr hook. > > > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > --- > > fs/xattr.c | 1 + > > include/linux/lsm_hook_defs.h | 2 ++ > > include/linux/security.h | 5 +++++ > > security/security.c | 14 ++++++++++++++ > > 4 files changed, 22 insertions(+) > > > > diff --git a/fs/xattr.c b/fs/xattr.c > > index 14a7eb3c8fa..10c959d9fc6 100644 > > --- a/fs/xattr.c > > +++ b/fs/xattr.c > > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, > > > > if (!error) { > > fsnotify_xattr(dentry); > > + security_inode_post_removexattr(dentry, name); > > evm_inode_post_removexattr(dentry, name); > > } > > Nothing wrong with this, but other places in this function test "if > (error) goto ...". Perhaps it is time to clean this up. > > > > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > > index eedefbcdde3..2ae5224d967 100644 > > --- a/include/linux/lsm_hook_defs.h > > +++ b/include/linux/lsm_hook_defs.h > > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) > > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) > > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, > > struct dentry *dentry, const char *name) > > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, > > + const char *name) > > @Christian should the security_inode_removexattr() and > security_inode_post_removexattr() arguments be the same? Probably this got lost. Christian, should security_inode_post_removexattr() have the idmap parameter as well? Thanks Roberto > > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, > > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) > > LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap, >
On Wed, Aug 30, 2023 at 11:31:35AM +0200, Roberto Sassu wrote: > On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote: > > Hi Roberto, > > > > On Fri, 2023-03-03 at 19:18 +0100, 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_removexattr hook. > > > > > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > > > --- > > > fs/xattr.c | 1 + > > > include/linux/lsm_hook_defs.h | 2 ++ > > > include/linux/security.h | 5 +++++ > > > security/security.c | 14 ++++++++++++++ > > > 4 files changed, 22 insertions(+) > > > > > > diff --git a/fs/xattr.c b/fs/xattr.c > > > index 14a7eb3c8fa..10c959d9fc6 100644 > > > --- a/fs/xattr.c > > > +++ b/fs/xattr.c > > > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, > > > > > > if (!error) { > > > fsnotify_xattr(dentry); > > > + security_inode_post_removexattr(dentry, name); > > > evm_inode_post_removexattr(dentry, name); > > > } > > > > Nothing wrong with this, but other places in this function test "if > > (error) goto ...". Perhaps it is time to clean this up. > > > > > > > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > > > index eedefbcdde3..2ae5224d967 100644 > > > --- a/include/linux/lsm_hook_defs.h > > > +++ b/include/linux/lsm_hook_defs.h > > > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) > > > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) > > > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, > > > struct dentry *dentry, const char *name) > > > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, > > > + const char *name) > > > > @Christian should the security_inode_removexattr() and > > security_inode_post_removexattr() arguments be the same? > > Probably this got lost. > > Christian, should security_inode_post_removexattr() have the idmap > parameter as well? Only if you call anything from any implementers of the hook that needs access to the idmap.
diff --git a/fs/xattr.c b/fs/xattr.c index 14a7eb3c8fa..10c959d9fc6 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap, if (!error) { fsnotify_xattr(dentry); + security_inode_post_removexattr(dentry, name); evm_inode_post_removexattr(dentry, name); } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index eedefbcdde3..2ae5224d967 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap, struct dentry *dentry, const char *name) +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(int, 0, inode_get_acl, struct mnt_idmap *idmap, diff --git a/include/linux/security.h b/include/linux/security.h index 64224216f6c..b511f608958 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -373,6 +373,7 @@ int security_inode_getxattr(struct dentry *dentry, const char *name); int security_inode_listxattr(struct dentry *dentry); int security_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name); +void security_inode_post_removexattr(struct dentry *dentry, const char *name); int security_inode_need_killpriv(struct dentry *dentry); int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry); int security_inode_getsecurity(struct mnt_idmap *idmap, @@ -918,6 +919,10 @@ static inline int security_inode_removexattr(struct mnt_idmap *idmap, return cap_inode_removexattr(idmap, dentry, name); } +static inline void security_inode_post_removexattr(struct dentry *dentry, + const char *name) +{ } + static inline int security_inode_need_killpriv(struct dentry *dentry) { return cap_inode_need_killpriv(dentry); diff --git a/security/security.c b/security/security.c index 2dbf225f5d8..6bf4a92db94 100644 --- a/security/security.c +++ b/security/security.c @@ -2404,6 +2404,20 @@ int security_inode_removexattr(struct mnt_idmap *idmap, return evm_inode_removexattr(idmap, dentry, name); } +/** + * security_inode_post_removexattr() - Update the inode after a removexattr op + * @dentry: file + * @name: xattr name + * + * Update the inode after a successful removexattr operation. + */ +void security_inode_post_removexattr(struct dentry *dentry, const char *name) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_removexattr, dentry, name); +} + /** * security_inode_need_killpriv() - Check if security_inode_killpriv() required * @dentry: associated dentry