From 4349ae2aac8cb88ec0ab8219303d5ed071180ed9 Mon Sep 17 00:00:00 2001
From: John Johansen <john.johansen@canonical.com>
Date: Fri, 9 Jun 2017 16:06:21 -0700
Subject: [PATCH 55/65] apparmor: move path_link mediation to using labels
Git-commit: 8014370f1257619226b79cb6de8e28563fbbc070
Patch-mainline: v4.13-rc1
References: FATE#323500
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
security/apparmor/file.c | 101 ++++++++++++++++++++++-----------------
security/apparmor/include/file.h | 2 +-
security/apparmor/lsm.c | 3 +-
3 files changed, 59 insertions(+), 47 deletions(-)
diff --git a/security/apparmor/file.c b/security/apparmor/file.c
index 1b216f889131..eb4c3006af67 100644
--- a/security/apparmor/file.c
+++ b/security/apparmor/file.c
@@ -370,66 +370,40 @@ static inline bool xindex_is_subset(u32 link, u32 target)
return 1;
}
-/**
- * aa_path_link - Handle hard link permission check
- * @profile: the profile being enforced (NOT NULL)
- * @old_dentry: the target dentry (NOT NULL)
- * @new_dir: directory the new link will be created in (NOT NULL)
- * @new_dentry: the link being created (NOT NULL)
- *
- * Handle the permission test for a link & target pair. Permission
- * is encoded as a pair where the link permission is determined
- * first, and if allowed, the target is tested. The target test
- * is done from the point of the link match (not start of DFA)
- * making the target permission dependent on the link permission match.
- *
- * The subset test if required forces that permissions granted
- * on link are a subset of the permission granted to target.
- *
- * Returns: %0 if allowed else error
- */
-int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
- const struct path *new_dir, struct dentry *new_dentry)
+static int profile_path_link(struct aa_profile *profile,
+ const struct path *link, char *buffer,
+ const struct path *target, char *buffer2,
+ struct path_cond *cond)
{
- struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry };
- struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry };
- struct path_cond cond = {
- d_backing_inode(old_dentry)->i_uid,
- d_backing_inode(old_dentry)->i_mode
- };
- char *buffer = NULL, *buffer2 = NULL;
- const char *lname, *tname = NULL, *info = NULL;
- struct aa_perms lperms, perms;
+ const char *lname, *tname = NULL;
+ struct aa_perms lperms = {}, perms;
+ const char *info = NULL;
u32 request = AA_MAY_LINK;
unsigned int state;
int error;
- get_buffers(buffer, buffer2);
- lperms = nullperms;
-
- /* buffer freed below, lname is pointer in buffer */
- error = aa_path_name(&link, profile->path_flags, buffer, &lname,
- &info, profile->disconnected);
+ error = path_name(OP_LINK, &profile->label, link, profile->path_flags,
+ buffer, &lname, cond, AA_MAY_LINK);
if (error)
goto audit;
/* buffer2 freed below, tname is pointer in buffer2 */
- error = aa_path_name(&target, profile->path_flags, buffer2, &tname,
- &info, profile->disconnected);
+ error = path_name(OP_LINK, &profile->label, target, profile->path_flags,
+ buffer2, &tname, cond, AA_MAY_LINK);
if (error)
goto audit;
error = -EACCES;
/* aa_str_perms - handles the case of the dfa being NULL */
state = aa_str_perms(profile->file.dfa, profile->file.start, lname,
- &cond, &lperms);
+ cond, &lperms);
if (!(lperms.allow & AA_MAY_LINK))
goto audit;
/* test to see if target can be paired with link */
state = aa_dfa_null_transition(profile->file.dfa, state);
- aa_str_perms(profile->file.dfa, state, tname, &cond, &perms);
+ aa_str_perms(profile->file.dfa, state, tname, cond, &perms);
/* force audit/quiet masks for link are stored in the second entry
* in the link pair.
@@ -440,6 +414,7 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
if (!(perms.allow & AA_MAY_LINK)) {
info = "target restricted";
+ lperms = perms;
goto audit;
}
@@ -447,10 +422,10 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
if (!(perms.allow & AA_LINK_SUBSET))
goto done_tests;
- /* Do link perm subset test requiring allowed permission on link are a
- * subset of the allowed permissions on target.
+ /* Do link perm subset test requiring allowed permission on link are
+ * a subset of the allowed permissions on target.
*/
- aa_str_perms(profile->file.dfa, profile->file.start, tname, &cond,
+ aa_str_perms(profile->file.dfa, profile->file.start, tname, cond,
&perms);
/* AA_MAY_LINK is not considered in the subset test */
@@ -472,8 +447,46 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
error = 0;
audit:
- error = aa_audit_file(profile, &lperms, OP_LINK, request,
- lname, tname, NULL, cond.uid, info, error);
+ return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname,
+ NULL, cond->uid, info, error);
+}
+
+/**
+ * aa_path_link - Handle hard link permission check
+ * @label: the label being enforced (NOT NULL)
+ * @old_dentry: the target dentry (NOT NULL)
+ * @new_dir: directory the new link will be created in (NOT NULL)
+ * @new_dentry: the link being created (NOT NULL)
+ *
+ * Handle the permission test for a link & target pair. Permission
+ * is encoded as a pair where the link permission is determined
+ * first, and if allowed, the target is tested. The target test
+ * is done from the point of the link match (not start of DFA)
+ * making the target permission dependent on the link permission match.
+ *
+ * The subset test if required forces that permissions granted
+ * on link are a subset of the permission granted to target.
+ *
+ * Returns: %0 if allowed else error
+ */
+int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
+ const struct path *new_dir, struct dentry *new_dentry)
+{
+ struct path link = { new_dir->mnt, new_dentry };
+ struct path target = { new_dir->mnt, old_dentry };
+ struct path_cond cond = {
+ d_backing_inode(old_dentry)->i_uid,
+ d_backing_inode(old_dentry)->i_mode
+ };
+ char *buffer = NULL, *buffer2 = NULL;
+ struct aa_profile *profile;
+ int error;
+
+ /* buffer freed below, lname is pointer in buffer */
+ get_buffers(buffer, buffer2);
+ error = fn_for_each_confined(label, profile,
+ profile_path_link(profile, &link, buffer, &target,
+ buffer2, &cond));
put_buffers(buffer, buffer2);
return error;
diff --git a/security/apparmor/include/file.h b/security/apparmor/include/file.h
index 8daad14c47fd..001e40073ff9 100644
--- a/security/apparmor/include/file.h
+++ b/security/apparmor/include/file.h
@@ -197,7 +197,7 @@ int aa_path_perm(const char *op, struct aa_label *label,
const struct path *path, int flags, u32 request,
struct path_cond *cond);
-int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
+int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
const struct path *new_dir, struct dentry *new_dentry);
int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index d0c5721aa8b3..7a986763b2b7 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -332,8 +332,7 @@ static int apparmor_path_link(struct dentry *old_dentry, const struct path *new_
label = begin_current_label_crit_section();
if (!unconfined(label))
- error = aa_path_link(labels_profile(label), old_dentry, new_dir,
- new_dentry);
+ error = aa_path_link(label, old_dentry, new_dir, new_dentry);
end_current_label_crit_section(label);
return error;
--
2.12.3