Date: Thu, 15 Apr 2021 09:50:09 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: bbf7a4e878ed - main - O_PATH: allow vnode kevent filter on such files Message-ID: <202104150950.13F9o9Sx069518@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=bbf7a4e878ed6828d13c7029c128a7e60dc25391 commit bbf7a4e878ed6828d13c7029c128a7e60dc25391 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2021-04-07 18:31:48 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2021-04-15 09:49:18 +0000 O_PATH: allow vnode kevent filter on such files if VREAD access is checked as allowed during open Requested by: wulf Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D29323 --- lib/libc/sys/open.2 | 3 +++ sys/kern/kern_descrip.c | 2 +- sys/kern/vfs_syscalls.c | 3 ++- sys/kern/vfs_vnops.c | 14 +++++++++++++- sys/sys/fcntl.h | 2 ++ sys/sys/file.h | 1 + 6 files changed, 22 insertions(+), 3 deletions(-) diff --git a/lib/libc/sys/open.2 b/lib/libc/sys/open.2 index 06a877e34460..a7806df69daf 100644 --- a/lib/libc/sys/open.2 +++ b/lib/libc/sys/open.2 @@ -342,6 +342,9 @@ can be passed over a socket using a .Dv SCM_RIGHTS message +.It Xr kqueue 2 +using for +.Dv EVFILT_VNODE .El But operations like .Xr read 2 , diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index a28e94634326..30ac40ffe296 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -4988,7 +4988,7 @@ struct fileops path_fileops = { .fo_truncate = badfo_truncate, .fo_ioctl = badfo_ioctl, .fo_poll = path_poll, - .fo_kqfilter = badfo_kqfilter, + .fo_kqfilter = vn_kqfilter_opath, .fo_stat = vn_statfile, .fo_close = path_close, .fo_chmod = badfo_chmod, diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c index 9130843f6761..43104a472b5b 100644 --- a/sys/kern/vfs_syscalls.c +++ b/sys/kern/vfs_syscalls.c @@ -1192,7 +1192,8 @@ kern_openat(struct thread *td, int fd, const char *path, enum uio_seg pathseg, KASSERT(vp->v_type != VFIFO || (flags & O_PATH) != 0, ("Unexpected fifo fp %p vp %p", fp, vp)); if ((flags & O_PATH) != 0) { - finit_vnode(fp, flags, NULL, &path_fileops); + finit(fp, (flags & FMASK) | (fp->f_flag & FKQALLOWED), + DTYPE_VNODE, NULL, &path_fileops); vhold(vp); vunref(vp); } else { diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index bb9ee2cceb79..9da35721def4 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -426,8 +426,12 @@ vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, if (error != 0) return (error); } - if ((fmode & O_PATH) != 0) + if ((fmode & O_PATH) != 0) { + error = VOP_ACCESS(vp, VREAD, cred, td); + if (error == 0) + fp->f_flag |= FKQALLOWED; return (0); + } if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) vn_lock(vp, LK_UPGRADE | LK_RETRY); @@ -2139,6 +2143,14 @@ vn_kqfilter(struct file *fp, struct knote *kn) return (VOP_KQFILTER(fp->f_vnode, kn)); } +int +vn_kqfilter_opath(struct file *fp, struct knote *kn) +{ + if ((fp->f_flag & FKQALLOWED) == 0) + return (EBADF); + return (vn_kqfilter(fp, kn)); +} + /* * Simplified in-kernel wrapper calls for extended attribute access. * Both calls pass in a NULL credential, authorizing as "kernel" access. diff --git a/sys/sys/fcntl.h b/sys/sys/fcntl.h index c328abaa02af..58d46ae26338 100644 --- a/sys/sys/fcntl.h +++ b/sys/sys/fcntl.h @@ -153,6 +153,8 @@ typedef __pid_t pid_t; #define FREVOKE O_VERIFY /* Only for fo_close() from half-succeeded open */ #define FOPENFAILED O_TTY_INIT +/* Only for O_PATH files which passed ACCESS FREAD check on open */ +#define FKQALLOWED O_RESOLVE_BENEATH /* convert from open() flags to/from fflags; convert O_RD/WR to FREAD/FWRITE */ #define FFLAGS(oflags) ((oflags) & O_EXEC ? (oflags) : (oflags) + 1) diff --git a/sys/sys/file.h b/sys/sys/file.h index 9237ee5ceb9d..b16e23bdfbcf 100644 --- a/sys/sys/file.h +++ b/sys/sys/file.h @@ -267,6 +267,7 @@ fo_stat_t vn_statfile; fo_sendfile_t vn_sendfile; fo_seek_t vn_seek; fo_fill_kinfo_t vn_fill_kinfo; +fo_kqfilter_t vn_kqfilter_opath; int vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif); void finit(struct file *, u_int, short, void *, struct fileops *);
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