From: Dr. David Alan Gilbert linux@treblig.org
[ 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 linux@treblig.org Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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;