[PATCH 5.15 001/374] f2fs: explicitly null-terminate the xattr list

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5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Biggers <ebiggers@xxxxxxxxxx>

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@xxxxxxxxxx>
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/f2fs/xattr.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -745,6 +745,12 @@ static int __f2fs_setxattr(struct inode
 		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);






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