From 282c335ad1bf4d21fcedff132e19995c24c09adc Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 8 May 2024 06:21:33 +0200 Subject: Adding upstream version 4.19.304. Signed-off-by: Daniel Baumann --- fs/attr.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'fs/attr.c') diff --git a/fs/attr.c b/fs/attr.c index 4d2541c1e..f064f08f5 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -256,9 +256,25 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de } if ((ia_valid & ATTR_MODE)) { - umode_t amode = attr->ia_mode; + /* + * Don't allow changing the mode of symlinks: + * + * (1) The vfs doesn't take the mode of symlinks into account + * during permission checking. + * (2) This has never worked correctly. Most major filesystems + * did return EOPNOTSUPP due to interactions with POSIX ACLs + * but did still updated the mode of the symlink. + * This inconsistency led system call wrapper providers such + * as libc to block changing the mode of symlinks with + * EOPNOTSUPP already. + * (3) To even do this in the first place one would have to use + * specific file descriptors and quite some effort. + */ + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + /* Flag setting protected by i_mutex */ - if (is_sxid(amode)) + if (is_sxid(attr->ia_mode)) inode->i_flags &= ~S_NOSEC; } -- cgit v1.2.3