From: Eric Biggers <ebiggers@google.com>
Date: Tue, 7 Nov 2023 04:44:34 +0000 (-0800)
Subject: f2fs: explicitly null-terminate the xattr list
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=32a6cfc67675ee96fe107aeed5af9776fec63f11;p=users%2Fdwmw2%2Flinux.git

f2fs: explicitly null-terminate the xattr list

commit e26b6d39270f5eab0087453d9b544189a38c8564 upstream.

When setting an xattr, explicitly null-terminate the xattr list.  This
eliminates the fragile assumption that the unused xattr space is always
zeroed.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 797ac505a075a..1a18936bc583b 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -745,6 +745,12 @@ static int __f2fs_setxattr(struct inode *inode, int index,
 		memcpy(pval, value, size);
 		last->e_value_size = cpu_to_le16(size);
 		new_hsize += newsize;
+		/*
+		 * Explicitly add the null terminator.  The unused xattr space
+		 * is supposed to always be zeroed, which would make this
+		 * unnecessary, but don't depend on that.
+		 */
+		*(u32 *)((u8 *)last + newsize) = 0;
 	}
 
 	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);