From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> Expand the check in should_remove_suid() to keep privileges for CAP_FSETID in s_user_ns rather than init_user_ns. Patch v4 is available: https://patchwork.kernel.org/patch/8944621/ --EWB Changed from ns_capable(sb->s_user_ns, ) to capable_wrt_inode_uidgid Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Serge Hallyn <serge@xxxxxxxxxx> Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> Signed-off-by: Dongsu Park <dongsu@xxxxxxxxxx> --- fs/inode.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index fd401028..6459a437 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1749,7 +1749,8 @@ EXPORT_SYMBOL(touch_atime); */ int should_remove_suid(struct dentry *dentry) { - umode_t mode = d_inode(dentry)->i_mode; + struct inode *inode = d_inode(dentry); + umode_t mode = inode->i_mode; int kill = 0; /* suid always must be killed */ @@ -1763,7 +1764,8 @@ int should_remove_suid(struct dentry *dentry) if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; - if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) + if (unlikely(kill && !capable_wrt_inode_uidgid(inode, CAP_FSETID) && + S_ISREG(mode))) return kill; return 0; -- 2.13.6
