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| author | Mickaël Salaün <mic@digikod.net> | 2022-05-06 18:10:56 +0200 |
|---|---|---|
| committer | Mickaël Salaün <mic@digikod.net> | 2022-05-23 13:27:58 +0200 |
| commit | 100f59d964050020285f0c8264ce520f0c406c13 (patch) | |
| tree | 037d009604dce35f82e15cdc324258d39dbaed9b /security/apparmor | |
| parent | 9da82b20fde95814af721a2a7b1796a5b4a3d78e (diff) | |
| download | linux-100f59d964050020285f0c8264ce520f0c406c13.tar.gz | |
LSM: Remove double path_rename hook calls for RENAME_EXCHANGE
In order to be able to identify a file exchange with renameat2(2) and RENAME_EXCHANGE, which will be useful for Landlock [1], propagate the rename flags to LSMs. This may also improve performance because of the switch from two set of LSM hook calls to only one, and because LSMs using this hook may optimize the double check (e.g. only one lock, reduce the number of path walks). AppArmor, Landlock and Tomoyo are updated to leverage this change. This should not change the current behavior (same check order), except (different level of) speed boosts. [1] https://lore.kernel.org/r/20220221212522.320243-1-mic@digikod.net Cc: James Morris <jmorris@namei.org> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Serge E. Hallyn <serge@hallyn.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20220506161102.525323-7-mic@digikod.net
Diffstat (limited to 'security/apparmor')
| -rw-r--r-- | security/apparmor/lsm.c | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 4f0eecb67dde..900bc540656a 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -354,13 +354,16 @@ static int apparmor_path_link(struct dentry *old_dentry, const struct path *new_ } static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_dentry, - const struct path *new_dir, struct dentry *new_dentry) + const struct path *new_dir, struct dentry *new_dentry, + const unsigned int flags) { struct aa_label *label; int error = 0; if (!path_mediated_fs(old_dentry)) return 0; + if ((flags & RENAME_EXCHANGE) && !path_mediated_fs(new_dentry)) + return 0; label = begin_current_label_crit_section(); if (!unconfined(label)) { @@ -374,10 +377,27 @@ static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_d d_backing_inode(old_dentry)->i_mode }; - error = aa_path_perm(OP_RENAME_SRC, label, &old_path, 0, - MAY_READ | AA_MAY_GETATTR | MAY_WRITE | - AA_MAY_SETATTR | AA_MAY_DELETE, - &cond); + if (flags & RENAME_EXCHANGE) { + struct path_cond cond_exchange = { + i_uid_into_mnt(mnt_userns, d_backing_inode(new_dentry)), + d_backing_inode(new_dentry)->i_mode + }; + + error = aa_path_perm(OP_RENAME_SRC, label, &new_path, 0, + MAY_READ | AA_MAY_GETATTR | MAY_WRITE | + AA_MAY_SETATTR | AA_MAY_DELETE, + &cond_exchange); + if (!error) + error = aa_path_perm(OP_RENAME_DEST, label, &old_path, + 0, MAY_WRITE | AA_MAY_SETATTR | + AA_MAY_CREATE, &cond_exchange); + } + + if (!error) + error = aa_path_perm(OP_RENAME_SRC, label, &old_path, 0, + MAY_READ | AA_MAY_GETATTR | MAY_WRITE | + AA_MAY_SETATTR | AA_MAY_DELETE, + &cond); if (!error) error = aa_path_perm(OP_RENAME_DEST, label, &new_path, 0, MAY_WRITE | AA_MAY_SETATTR | |