Actually maximum length of a valid entry value is not
->s_blocksize because header, last entry and entry
name will also occupy some spaces. This patch
strengthens the value length check and return -ERANGE
when the length is larger than allowed maximum length.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxx>
---
fs/ext2/xattr.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index f1f857b83b45..425c8e29d3cb 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -399,7 +399,7 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
struct buffer_head *bh = NULL;
struct ext2_xattr_header *header = NULL;
struct ext2_xattr_entry *here, *last;
- size_t name_len, free, min_offs = sb->s_blocksize;
+ size_t name_len, free, min_offs = sb->s_blocksize, max_len;
int not_found = 1, error;
char *end;
@@ -423,7 +423,10 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
- if (name_len > 255 || value_len > sb->s_blocksize)
+ max_len = sb->s_blocksize - sizeof(struct ext2_xattr_header)
+ - sizeof(__u32);
+ if (name_len > 255 ||
+ EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len) > max_len)
return -ERANGE;
down_write(&EXT2_I(inode)->xattr_sem);
if (EXT2_I(inode)->i_file_acl) {
--
2.20.1
