[PATCH v15 23/26] ima: Show owning user namespace's uid and gid when displaying policy

[Stefan Berger <stefanb@xxxxxxxxxxxxx>]

Show the uid and gid values relative to the user namespace that opened
the IMA policy file. The effect of this change is that when one displays
the policy from the user namespace that originally set the policy,
the same uid and gid values are shown in the policy as those that were
used when the policy was set.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
Reviewed-by: Serge Hallyn <serge@xxxxxxxxxx>

---
v13:
  - Rephrased commit message following Serge's suggestion

v9:
  - use seq_user_ns and from_k{g,u}id_munged()
---
 security/integrity/ima/ima_policy.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 10b85642188f..bcd3227630bb 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -2127,6 +2127,7 @@ static void ima_policy_show_appraise_algos(struct seq_file *m,
 
 int ima_policy_show(struct seq_file *m, void *v)
 {
+	struct user_namespace *user_ns = seq_user_ns(m);
 	struct ima_rule_entry *entry = v;
 	int i;
 	char tbuf[64] = {0,};
@@ -2212,7 +2213,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_UID) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kuid_munged(user_ns, entry->uid));
 		if (entry->uid_op == &uid_gt)
 			seq_printf(m, pt(Opt_uid_gt), tbuf);
 		else if (entry->uid_op == &uid_lt)
@@ -2223,7 +2225,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_EUID) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kuid_munged(user_ns, entry->uid));
 		if (entry->uid_op == &uid_gt)
 			seq_printf(m, pt(Opt_euid_gt), tbuf);
 		else if (entry->uid_op == &uid_lt)
@@ -2234,7 +2237,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_GID) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kgid_munged(user_ns, entry->gid));
 		if (entry->gid_op == &gid_gt)
 			seq_printf(m, pt(Opt_gid_gt), tbuf);
 		else if (entry->gid_op == &gid_lt)
@@ -2245,7 +2249,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_EGID) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kgid_munged(user_ns, entry->gid));
 		if (entry->gid_op == &gid_gt)
 			seq_printf(m, pt(Opt_egid_gt), tbuf);
 		else if (entry->gid_op == &gid_lt)
@@ -2256,7 +2261,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_FOWNER) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kuid_munged(user_ns, entry->fowner));
 		if (entry->fowner_op == &vfsuid_gt_kuid)
 			seq_printf(m, pt(Opt_fowner_gt), tbuf);
 		else if (entry->fowner_op == &vfsuid_lt_kuid)
@@ -2267,7 +2273,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 
 	if (entry->flags & IMA_FGROUP) {
-		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
+		snprintf(tbuf, sizeof(tbuf),
+			 "%d", from_kgid_munged(user_ns, entry->fgroup));
 		if (entry->fgroup_op == &vfsgid_gt_kgid)
 			seq_printf(m, pt(Opt_fgroup_gt), tbuf);
 		else if (entry->fgroup_op == &vfsgid_lt_kgid)
-- 
2.37.3