From cff32466bf851bf29cd491d8a3cbeb4dc4a36ab6 Mon Sep 17 00:00:00 2001

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Date: Fri, 24 Sep 2021 17:53:56 +0300

Subject: [Backport cff32466bf85] src: Refactoring of ntfs_set_ea

Make code more readable.

Don't try to read zero bytes.

Add warning when size of exteneded attribute exceeds limit.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

---

 src/xattr.c | 31 +++++++++++++++++--------------

 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/src/xattr.c b/src/xattr.c

index 29f571b53083ea86d3091834749b8d87dec9d69c..cdc01877227a509398c9c8b203382ac2f9858a5e 100644

--- a/src/xattr.c

+++ b/src/xattr.c

@@ -75,6 +75,7 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,

 			size_t add_bytes, const struct EA_INFO **info)

 {

 	int err;

+	struct ntfs_sb_info *sbi = ni->mi.sbi;

 	struct ATTR_LIST_ENTRY *le = NULL;

 	struct ATTRIB *attr_info, *attr_ea;

 	void *ea_p;

@@ -99,10 +100,10 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,

 	/* Check Ea limit. */

 	size = le32_to_cpu((*info)->size);

-	if (size > ni->mi.sbi->ea_max_size)

+	if (size > sbi->ea_max_size)

 		return -EFBIG;

-	if (attr_size(attr_ea) > ni->mi.sbi->ea_max_size)

+	if (attr_size(attr_ea) > sbi->ea_max_size)

 		return -EFBIG;

 	/* Allocate memory for packed Ea. */

@@ -110,15 +111,16 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea,

 	if (!ea_p)

 		return -ENOMEM;

-	if (attr_ea->non_res) {

+	if (!size) {

+		;

+	} else if (attr_ea->non_res) {

 		struct runs_tree run;

 		run_init(&run;;

 		err = attr_load_runs(attr_ea, ni, &run, NULL);

 		if (!err)

-			err = ntfs_read_run_nb(ni->mi.sbi, &run, 0, ea_p, size,

-					       NULL);

+			err = ntfs_read_run_nb(sbi, &run, 0, ea_p, size, NULL);

 		run_close(&run;;

 		if (err)

@@ -366,21 +368,22 @@ static noinline int ntfs_set_ea(struct inode *inode, const char *name,

 	new_ea->name[name_len] = 0;

 	memcpy(new_ea->name + name_len + 1, value, val_size);

 	new_pack = le16_to_cpu(ea_info.size_pack) + packed_ea_size(new_ea);

-

-	/* Should fit into 16 bits. */

-	if (new_pack > 0xffff) {

-		err = -EFBIG; // -EINVAL?

-		goto out;

-	}

 	ea_info.size_pack = cpu_to_le16(new_pack);

-

 	/* New size of ATTR_EA. */

 	size += add;

-	if (size > sbi->ea_max_size) {

+	ea_info.size = cpu_to_le32(size);

+

+	/*

+	 * 1. Check ea_info.size_pack for overflow.

+	 * 2. New attibute size must fit value from $AttrDef

+	 */

+	if (new_pack > 0xffff || size > sbi->ea_max_size) {

+		ntfs_inode_warn(

+			inode,

+			"The size of extended attributes must not exceed 64KiB");

 		err = -EFBIG; // -EINVAL?

 		goto out;

 	}

-	ea_info.size = cpu_to_le32(size);

 update_ea:

-- 

2.31.1