From ccb6bdf0b7b64beb8c0808cef0bcf9e893504830 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Sat, 22 Oct 2022 21:39:14 +0100 Subject: [PATCH] jfs: Fix fortify moan in symlink [ Upstream commit ebe060369f8d6e4588b115f252bebf5ba4d64350 ] JFS has in jfs_incore.h: /* _inline may overflow into _inline_ea when needed */ /* _inline_ea may overlay the last part of * file._xtroot if maxentry = XTROOTINITSLOT */ union { struct { /* 128: inline symlink */ unchar _inline[128]; /* 128: inline extended attr */ unchar _inline_ea[128]; }; unchar _inline_all[256]; and currently the symlink code copies into _inline; if this is larger than 128 bytes it triggers a fortify warning of the form: memcpy: detected field-spanning write (size 132) of single field "ip->i_link" at fs/jfs/namei.c:950 (size 18446744073709551615) when it's actually OK. Copy it into _inline_all instead. Reported-by: syzbot+5fc38b2ddbbca7f5c680@syzkaller.appspotmail.com Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Kees Cook Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin --- fs/jfs/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c index 9db4f5789c0e..4fbbf88435e6 100644 --- a/fs/jfs/namei.c +++ b/fs/jfs/namei.c @@ -946,7 +946,7 @@ static int jfs_symlink(struct user_namespace *mnt_userns, struct inode *dip, if (ssize <= IDATASIZE) { ip->i_op = &jfs_fast_symlink_inode_operations; - ip->i_link = JFS_IP(ip)->i_inline; + ip->i_link = JFS_IP(ip)->i_inline_all; memcpy(ip->i_link, name, ssize); ip->i_size = ssize - 1;