userns: Convert extN to support kuids and kgids in posix acls

Convert ext2, ext3, and ext4 to fully support the posix acl changes,
using e_uid e_gid instead e_id.

Enabled building with posix acls enabled, all filesystems supporting
user namespaces, now also support posix acls when user namespaces are enabled.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

3 files changed, 60 insertions, 23 deletions

diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
index 70bb1bccc957..110b6b371a4e 100644
--- a/fs/ext2/acl.c
+++ b/fs/ext2/acl.c
@@ -53,16 +53,23 @@ ext2_acl_from_disk(const void *value, size_t size)
 			case ACL_OTHER:
 				value = (char *)value +
 					sizeof(ext2_acl_entry_short);
-				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 				break;
 
 			case ACL_USER:
+				value = (char *)value + sizeof(ext2_acl_entry);
+				if ((char *)value > end)
+					goto fail;
+				acl->a_entries[n].e_uid =
+					make_kuid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
+				break;
 			case ACL_GROUP:
 				value = (char *)value + sizeof(ext2_acl_entry);
 				if ((char *)value > end)
 					goto fail;
-				acl->a_entries[n].e_id =
-					le32_to_cpu(entry->e_id);
+				acl->a_entries[n].e_gid =
+					make_kgid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
 				break;
 
 			default:
@@ -96,14 +103,19 @@ ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
 	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
 	e = (char *)ext_acl + sizeof(ext2_acl_header);
 	for (n=0; n < acl->a_count; n++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 		ext2_acl_entry *entry = (ext2_acl_entry *)e;
-		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
-		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-		switch(acl->a_entries[n].e_tag) {
+		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
 			case ACL_USER:
+				entry->e_id = cpu_to_le32(
+					from_kuid(&init_user_ns, acl_e->e_uid));
+				e += sizeof(ext2_acl_entry);
+				break;
 			case ACL_GROUP:
-				entry->e_id =
-					cpu_to_le32(acl->a_entries[n].e_id);
+				entry->e_id = cpu_to_le32(
+					from_kgid(&init_user_ns, acl_e->e_gid));
 				e += sizeof(ext2_acl_entry);
 				break;
 
diff --git a/fs/ext3/acl.c b/fs/ext3/acl.c
index 2cf6a8044c80..dbb5ad59a7fc 100644
--- a/fs/ext3/acl.c
+++ b/fs/ext3/acl.c
@@ -48,16 +48,23 @@ ext3_acl_from_disk(const void *value, size_t size)
 			case ACL_OTHER:
 				value = (char *)value +
 					sizeof(ext3_acl_entry_short);
-				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 				break;
 
 			case ACL_USER:
+				value = (char *)value + sizeof(ext3_acl_entry);
+				if ((char *)value > end)
+					goto fail;
+				acl->a_entries[n].e_uid =
+					make_kuid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
+				break;
 			case ACL_GROUP:
 				value = (char *)value + sizeof(ext3_acl_entry);
 				if ((char *)value > end)
 					goto fail;
-				acl->a_entries[n].e_id =
-					le32_to_cpu(entry->e_id);
+				acl->a_entries[n].e_gid =
+					make_kgid(&init_user_ns,
+						  le32_to_cpu(entry->e_id));
 				break;
 
 			default:
@@ -91,14 +98,19 @@ ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
 	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
 	e = (char *)ext_acl + sizeof(ext3_acl_header);
 	for (n=0; n < acl->a_count; n++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 		ext3_acl_entry *entry = (ext3_acl_entry *)e;
-		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
-		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-		switch(acl->a_entries[n].e_tag) {
+		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch(acl_e->e_tag) {
 			case ACL_USER:
+				entry->e_id = cpu_to_le32(
+					from_kuid(&init_user_ns, acl_e->e_uid));
+				e += sizeof(ext3_acl_entry);
+				break;
 			case ACL_GROUP:
-				entry->e_id =
-					cpu_to_le32(acl->a_entries[n].e_id);
+				entry->e_id = cpu_to_le32(
+					from_kgid(&init_user_ns, acl_e->e_gid));
 				e += sizeof(ext3_acl_entry);
 				break;
 
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 42b95fccfb2f..d3c5b88fd89f 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -55,16 +55,23 @@ ext4_acl_from_disk(const void *value, size_t size)
 		case ACL_OTHER:
 			value = (char *)value +
 				sizeof(ext4_acl_entry_short);
-			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
 			break;
 
 		case ACL_USER:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
+				goto fail;
+			acl->a_entries[n].e_uid =
+				make_kuid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
+			break;
 		case ACL_GROUP:
 			value = (char *)value + sizeof(ext4_acl_entry);
 			if ((char *)value > end)
 				goto fail;
-			acl->a_entries[n].e_id =
-				le32_to_cpu(entry->e_id);
+			acl->a_entries[n].e_gid =
+				make_kgid(&init_user_ns,
+					  le32_to_cpu(entry->e_id));
 			break;
 
 		default:
@@ -98,13 +105,19 @@ ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
 	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
 	e = (char *)ext_acl + sizeof(ext4_acl_header);
 	for (n = 0; n < acl->a_count; n++) {
+		const struct posix_acl_entry *acl_e = &acl->a_entries[n];
 		ext4_acl_entry *entry = (ext4_acl_entry *)e;
-		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
-		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-		switch (acl->a_entries[n].e_tag) {
+		entry->e_tag  = cpu_to_le16(acl_e->e_tag);
+		entry->e_perm = cpu_to_le16(acl_e->e_perm);
+		switch (acl_e->e_tag) {
 		case ACL_USER:
+			entry->e_id = cpu_to_le32(
+				from_kuid(&init_user_ns, acl_e->e_uid));
+			e += sizeof(ext4_acl_entry);
+			break;
 		case ACL_GROUP:
-			entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
+			entry->e_id = cpu_to_le32(
+				from_kgid(&init_user_ns, acl_e->e_gid));
 			e += sizeof(ext4_acl_entry);
 			break;