FAILED: patch "[PATCH] ext4: Don't clear SGID when inheriting ACLs" failed to apply to 4.12-stable tree

From a3bb2d5587521eea6dab2d05326abb0afb460abd Mon Sep 17 00:00:00 2001

The patch below does not apply to the 4.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

------------------ original commit in Linus's tree ------------------

From a3bb2d5587521eea6dab2d05326abb0afb460abd Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Sun, 30 Jul 2017 23:33:01 -0400
Subject: [PATCH] ext4: Don't clear SGID when inheriting ACLs

When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.

Fix the problem by moving posix_acl_update_mode() out of __ext4_set_acl() into ext4_set_acl(). That way the function will not be called when inheriting ACLs which is what we want as it prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.

Fixes 073931017b49d9458aa351605b43a7e34598caef

CC [email protected]

Signed-off-by Theodore Ts'o <[email protected]>

Signed-off-by Jan Kara <[email protected]>

Reviewed-by Andreas Gruenbacher <[email protected]>

fs/ext4/acl.c +15 -13

index 2985cd0a640d..46ff2229ff5e 100644
@@ -189,18 +189,10 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	void *value = NULL;
 	size_t size = 0;
 	int error;
-	int update_mode = 0;
-	umode_t mode = inode->i_mode;
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
-		if (acl) {
-			error = posix_acl_update_mode(inode, &mode, &acl);
-			if (error)
-				return error;
-			update_mode = 1;
-		}
 		break;
 
 	case ACL_TYPE_DEFAULT:

@@ -224,11 +216,6 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	kfree(value);
 	if (!error) {
 		set_cached_acl(inode, type, acl);
-		if (update_mode) {
-			inode->i_mode = mode;
-			inode->i_ctime = current_time(inode);
-			ext4_mark_inode_dirty(handle, inode);
-		}
 	}
 
 	return error;

@@ -240,6 +227,8 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	handle_t *handle;
 	int error, credits, retries = 0;
 	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
+	umode_t mode = inode->i_mode;
+	int update_mode = 0;
 
 	error = dquot_initialize(inode);
 	if (error)

@@ -254,7 +243,20 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
+	if ((type == ACL_TYPE_ACCESS) && acl) {
+		error = posix_acl_update_mode(inode, &mode, &acl);
+		if (error)
+			goto out_stop;
+		update_mode = 1;
+	}
+
 	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
+	if (!error && update_mode) {
+		inode->i_mode = mode;
+		inode->i_ctime = current_time(inode);
+		ext4_mark_inode_dirty(handle, inode);
+	}
+out_stop:
 	ext4_journal_stop(handle);
 	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 		goto retry;

Quoted 5 lines · On Mon 07-08-17 14:44:54, [email protected] wrote:

The patch below does not apply to the 4.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Greg, I think you need to pick up also commit 397e434176bb "ext4: preserve i_mode if __ext4_set_acl() fails" which was not marked for stable but changes that function and probably it makes sense in stable as well.

Quoted 91 lines

------------------ original commit in Linus's tree ------------------

From a3bb2d5587521eea6dab2d05326abb0afb460abd Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Sun, 30 Jul 2017 23:33:01 -0400
Subject: [PATCH] ext4: Don't clear SGID when inheriting ACLs

When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit set, DIR1 is expected to have SGID bit set (and owning group equal to the owning group of 'DIR0'). However when 'DIR0' also has some default ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on 'DIR1' to get cleared if user is not member of the owning group.

Fix the problem by moving posix_acl_update_mode() out of __ext4_set_acl() into ext4_set_acl(). That way the function will not be called when inheriting ACLs which is what we want as it prevents SGID bit clearing and the mode has been properly set by posix_acl_create() anyway.

Fixes 073931017b49d9458aa351605b43a7e34598caef

CC [email protected]

Signed-off-by Theodore Ts'o <[email protected]>

Signed-off-by Jan Kara <[email protected]>

Reviewed-by Andreas Gruenbacher <[email protected]>

fs/ext4/acl.c +15 -13

index 2985cd0a640d..46ff2229ff5e 100644
@@ -189,18 +189,10 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	void *value = NULL;
 	size_t size = 0;
 	int error;
-	int update_mode = 0;
-	umode_t mode = inode->i_mode;
 
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
-		if (acl) {
-			error = posix_acl_update_mode(inode, &mode, &acl);
-			if (error)
-				return error;
-			update_mode = 1;
-		}
 		break;
 
 	case ACL_TYPE_DEFAULT:

@@ -224,11 +216,6 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	kfree(value);
 	if (!error) {
 		set_cached_acl(inode, type, acl);
-		if (update_mode) {
-			inode->i_mode = mode;
-			inode->i_ctime = current_time(inode);
-			ext4_mark_inode_dirty(handle, inode);
-		}
 	}
 
 	return error;

@@ -240,6 +227,8 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	handle_t *handle;
 	int error, credits, retries = 0;
 	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
+	umode_t mode = inode->i_mode;
+	int update_mode = 0;
 
 	error = dquot_initialize(inode);
 	if (error)

@@ -254,7 +243,20 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
+	if ((type == ACL_TYPE_ACCESS) && acl) {
+		error = posix_acl_update_mode(inode, &mode, &acl);
+		if (error)
+			goto out_stop;
+		update_mode = 1;
+	}
+
 	error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
+	if (!error && update_mode) {
+		inode->i_mode = mode;
+		inode->i_ctime = current_time(inode);
+		ext4_mark_inode_dirty(handle, inode);
+	}
+out_stop:
 	ext4_journal_stop(handle);
 	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 		goto retry;

Signature · 2 lines

Jan Kara <[email protected]>
SUSE Labs, CR