Message ID | 20230831104136.903180-17-roberto.sassu@huaweicloud.com (mailing list archive) |
---|---|
State | New |
Headers | show |
Series | security: Move IMA and EVM to the LSM infrastructure | expand |
On 8/31/2023 3:41 AM, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > In preparation for moving IMA and EVM to the LSM infrastructure, introduce > the path_post_mknod hook. Repeat of new LSM hook general comment: Would you please include some explanation of how an LSM would use this hook? You might start with a description of how it is used in IMA/EVM, and why that could be generally useful. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > fs/namei.c | 5 +++++ > include/linux/lsm_hook_defs.h | 3 +++ > include/linux/security.h | 9 +++++++++ > security/security.c | 19 +++++++++++++++++++ > 4 files changed, 36 insertions(+) > > diff --git a/fs/namei.c b/fs/namei.c > index 7dc4626859f0..c8c4ab26b52a 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -4061,6 +4061,11 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode, > dentry, mode, 0); > break; > } > + > + if (error) > + goto out2; > + > + security_path_post_mknod(idmap, &path, dentry, mode_stripped, dev); > out2: > done_path_create(&path, dentry); > if (retry_estale(error, lookup_flags)) { > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index 797f51da3f7d..b1634b5de98c 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -93,6 +93,9 @@ LSM_HOOK(int, 0, path_mkdir, const struct path *dir, struct dentry *dentry, > LSM_HOOK(int, 0, path_rmdir, const struct path *dir, struct dentry *dentry) > LSM_HOOK(int, 0, path_mknod, const struct path *dir, struct dentry *dentry, > umode_t mode, unsigned int dev) > +LSM_HOOK(void, LSM_RET_VOID, path_post_mknod, struct mnt_idmap *idmap, > + const struct path *dir, struct dentry *dentry, umode_t mode, > + unsigned int dev) > LSM_HOOK(int, 0, path_truncate, const struct path *path) > LSM_HOOK(int, 0, path_symlink, const struct path *dir, struct dentry *dentry, > const char *old_name) > diff --git a/include/linux/security.h b/include/linux/security.h > index 7871009d59ae..f210bd66e939 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -1842,6 +1842,9 @@ int security_path_mkdir(const struct path *dir, struct dentry *dentry, umode_t m > int security_path_rmdir(const struct path *dir, struct dentry *dentry); > int security_path_mknod(const struct path *dir, struct dentry *dentry, umode_t mode, > unsigned int dev); > +void security_path_post_mknod(struct mnt_idmap *idmap, const struct path *dir, > + struct dentry *dentry, umode_t mode, > + unsigned int dev); > int security_path_truncate(const struct path *path); > int security_path_symlink(const struct path *dir, struct dentry *dentry, > const char *old_name); > @@ -1876,6 +1879,12 @@ static inline int security_path_mknod(const struct path *dir, struct dentry *den > return 0; > } > > +static inline void security_path_post_mknod(struct mnt_idmap *idmap, > + const struct path *dir, > + struct dentry *dentry, umode_t mode, > + unsigned int dev) > +{ } > + > static inline int security_path_truncate(const struct path *path) > { > return 0; > diff --git a/security/security.c b/security/security.c > index 3e648aa9292c..56c1c1e66fd1 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1702,6 +1702,25 @@ int security_path_mknod(const struct path *dir, struct dentry *dentry, > } > EXPORT_SYMBOL(security_path_mknod); > > +/** > + * security_path_post_mknod() - Update inode security field after file creation > + * @idmap: idmap of the mount > + * @dir: parent directory > + * @dentry: new file > + * @mode: new file mode > + * @dev: device number > + * > + * Update inode security field after a file has been created. > + */ > +void security_path_post_mknod(struct mnt_idmap *idmap, const struct path *dir, > + struct dentry *dentry, umode_t mode, > + unsigned int dev) > +{ > + if (unlikely(IS_PRIVATE(d_backing_inode(dir->dentry)))) > + return; > + call_void_hook(path_post_mknod, idmap, dir, dentry, mode, dev); > +} > + > /** > * security_path_mkdir() - Check if creating a new directory is allowed > * @dir: parent directory
diff --git a/fs/namei.c b/fs/namei.c index 7dc4626859f0..c8c4ab26b52a 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4061,6 +4061,11 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode, dentry, mode, 0); break; } + + if (error) + goto out2; + + security_path_post_mknod(idmap, &path, dentry, mode_stripped, dev); out2: done_path_create(&path, dentry); if (retry_estale(error, lookup_flags)) { diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 797f51da3f7d..b1634b5de98c 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -93,6 +93,9 @@ LSM_HOOK(int, 0, path_mkdir, const struct path *dir, struct dentry *dentry, LSM_HOOK(int, 0, path_rmdir, const struct path *dir, struct dentry *dentry) LSM_HOOK(int, 0, path_mknod, const struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev) +LSM_HOOK(void, LSM_RET_VOID, path_post_mknod, struct mnt_idmap *idmap, + const struct path *dir, struct dentry *dentry, umode_t mode, + unsigned int dev) LSM_HOOK(int, 0, path_truncate, const struct path *path) LSM_HOOK(int, 0, path_symlink, const struct path *dir, struct dentry *dentry, const char *old_name) diff --git a/include/linux/security.h b/include/linux/security.h index 7871009d59ae..f210bd66e939 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1842,6 +1842,9 @@ int security_path_mkdir(const struct path *dir, struct dentry *dentry, umode_t m int security_path_rmdir(const struct path *dir, struct dentry *dentry); int security_path_mknod(const struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev); +void security_path_post_mknod(struct mnt_idmap *idmap, const struct path *dir, + struct dentry *dentry, umode_t mode, + unsigned int dev); int security_path_truncate(const struct path *path); int security_path_symlink(const struct path *dir, struct dentry *dentry, const char *old_name); @@ -1876,6 +1879,12 @@ static inline int security_path_mknod(const struct path *dir, struct dentry *den return 0; } +static inline void security_path_post_mknod(struct mnt_idmap *idmap, + const struct path *dir, + struct dentry *dentry, umode_t mode, + unsigned int dev) +{ } + static inline int security_path_truncate(const struct path *path) { return 0; diff --git a/security/security.c b/security/security.c index 3e648aa9292c..56c1c1e66fd1 100644 --- a/security/security.c +++ b/security/security.c @@ -1702,6 +1702,25 @@ int security_path_mknod(const struct path *dir, struct dentry *dentry, } EXPORT_SYMBOL(security_path_mknod); +/** + * security_path_post_mknod() - Update inode security field after file creation + * @idmap: idmap of the mount + * @dir: parent directory + * @dentry: new file + * @mode: new file mode + * @dev: device number + * + * Update inode security field after a file has been created. + */ +void security_path_post_mknod(struct mnt_idmap *idmap, const struct path *dir, + struct dentry *dentry, umode_t mode, + unsigned int dev) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dir->dentry)))) + return; + call_void_hook(path_post_mknod, idmap, dir, dentry, mode, dev); +} + /** * security_path_mkdir() - Check if creating a new directory is allowed * @dir: parent directory