From f9b923af34a6749c7703b957742f33cc02a485a2 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Wed, 7 Apr 2021 06:23:25 +0300 Subject: [PATCH] O_PATH: Allow to open symlink When O_NOFOLLOW is specified, namei() returns the symlink itself. In this case, open(O_PATH) should be allowed, to denote the location of symlink itself. Prevent O_EXEC in this case, execve(2) code is not ready to try to execute symlinks. Reported by: wulf Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D29323 --- sys/kern/vfs_vnops.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index 6339295b0556..bb9ee2cceb79 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -385,8 +385,10 @@ vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, accmode_t accmode; int error; - if (vp->v_type == VLNK) - return (EMLINK); + if (vp->v_type == VLNK) { + if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) + return (EMLINK); + } if (vp->v_type == VSOCK) return (EOPNOTSUPP); if (vp->v_type != VDIR && fmode & O_DIRECTORY)