[PATCH v2] f2fs: fix listxattr handling of corrupted xattr entries

[Keshav Verma <iganschel@gmail.com>]

Validate the xattr entry before reading its fields in f2fs_listxattr().
Return -EFSCORRUPTED when the entry is outside the valid xattr storage
area instead of returning a successful partial result.

Fixes: 688078e7f36c ("f2fs: fix to avoid memory leakage in f2fs_listxattr")
Cc: stable@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Keshav Verma <iganschel@gmail.com>
---
Changes in v2:
- Add Fixes tag.
- Add Reviewed-by tag.
- Add Cc: stable@kernel.org tag.

 fs/f2fs/xattr.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 610d5810074d..18f495db20d2 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -581,8 +581,6 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 		size_t prefix_len;
 		size_t size;
 
-		prefix = f2fs_xattr_prefix(entry->e_name_index, dentry);
-
 		if ((void *)(entry) + sizeof(__u32) > last_base_addr ||
 			(void *)XATTR_NEXT_ENTRY(entry) > last_base_addr) {
 			f2fs_err(F2FS_I_SB(inode), "list inode (%llu) has corrupted xattr",
@@ -590,9 +588,12 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 			set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_FSCK);
 			f2fs_handle_error(F2FS_I_SB(inode),
 						ERROR_CORRUPTED_XATTR);
-			break;
+			error = -EFSCORRUPTED;
+			goto cleanup;
 		}
 
+		prefix = f2fs_xattr_prefix(entry->e_name_index, dentry);
+
 		if (!prefix)
 			continue;
 
-- 
2.39.5