git: 994ed958ae05 - main - linux(4): Add a dedicated fstat() implementation
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Date: Fri, 28 Apr 2023 08:57:21 UTC
The branch main has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=994ed958ae0545faa86dd43b6e64bf7b64b9220b commit 994ed958ae0545faa86dd43b6e64bf7b64b9220b Author: Dmitry Chagin <dchagin@FreeBSD.org> AuthorDate: 2023-04-28 08:55:04 +0000 Commit: Dmitry Chagin <dchagin@FreeBSD.org> CommitDate: 2023-04-28 08:55:04 +0000 linux(4): Add a dedicated fstat() implementation In between kern_fstat() and translate_fd_major_minor(), another process having the same filedesc could modify or close fd. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D39763 --- sys/compat/linux/linux_stats.c | 75 +++++++++++++++++------------------------- 1 file changed, 31 insertions(+), 44 deletions(-) diff --git a/sys/compat/linux/linux_stats.c b/sys/compat/linux/linux_stats.c index dc1e50a4fa00..260709b23202 100644 --- a/sys/compat/linux/linux_stats.c +++ b/sys/compat/linux/linux_stats.c @@ -47,6 +47,8 @@ __FBSDID("$FreeBSD$"); #include <sys/ktrace.h> #endif +#include <security/audit/audit.h> + #ifdef COMPAT_LINUX32 #include <machine/../linux32/linux.h> #include <machine/../linux32/linux32_proto.h> @@ -59,6 +61,32 @@ __FBSDID("$FreeBSD$"); #include <compat/linux/linux_util.h> +static int +linux_kern_fstat(struct thread *td, int fd, struct stat *sbp) +{ + struct vnode *vp; + struct file *fp; + int error; + + AUDIT_ARG_FD(fd); + + error = fget(td, fd, &cap_fstat_rights, &fp); + if (__predict_false(error != 0)) + return (error); + + AUDIT_ARG_FILE(td->td_proc, fp); + + error = fo_stat(fp, sbp, td->td_ucred); + if (error == 0 && (vp = fp->f_vnode) != NULL) + translate_vnhook_major_minor(vp, sbp); + fdrop(fp, td); +#ifdef KTRACE + if (KTRPOINT(td, KTR_STRUCT)) + ktrstat_error(sbp, error); +#endif + return (error); +} + static int linux_kern_statat(struct thread *td, int flag, int fd, const char *path, enum uio_seg pathseg, struct stat *sbp) @@ -77,7 +105,7 @@ linux_kern_statat(struct thread *td, int flag, int fd, const char *path, if ((error = namei(&nd)) != 0) { if (error == ENOTDIR && (nd.ni_resflags & NIRES_EMPTYPATH) != 0) - error = kern_fstat(td, fd, sbp); + error = linux_kern_fstat(td, fd, sbp); return (error); } error = VOP_STAT(nd.ni_vp, sbp, td->td_ucred, NOCRED); @@ -111,45 +139,6 @@ linux_kern_lstat(struct thread *td, const char *path, enum uio_seg pathseg, } #endif -static void -translate_fd_major_minor(struct thread *td, int fd, struct stat *buf) -{ - struct file *fp; - struct vnode *vp; - struct mount *mp; - int major, minor; - - /* - * No capability rights required here. - */ - if ((!S_ISCHR(buf->st_mode) && !S_ISBLK(buf->st_mode)) || - fget(td, fd, &cap_no_rights, &fp) != 0) - return; - vp = fp->f_vnode; - if (vp != NULL && vn_isdisk(vp)) { - buf->st_mode &= ~S_IFMT; - buf->st_mode |= S_IFBLK; - } - if (vp != NULL && rootdevmp != NULL) { - mp = vp->v_mount; - __compiler_membar(); - if (mp != NULL && mp->mnt_vfc == rootdevmp->mnt_vfc) - buf->st_dev = rootdevmp->mnt_stat.f_fsid.val[0]; - } - if (linux_vn_get_major_minor(vp, &major, &minor) == 0) { - buf->st_rdev = (major << 8 | minor); - } else if (fp->f_type == DTYPE_PTS) { - struct tty *tp = fp->f_data; - - /* Convert the numbers for the slave device. */ - if (linux_driver_get_major_minor(devtoname(tp->t_dev), - &major, &minor) == 0) { - buf->st_rdev = (major << 8 | minor); - } - } - fdrop(fp, td); -} - /* * l_dev_t has the same encoding as dev_t in the latter's low 16 bits, so * truncation of a dev_t to 16 bits gives the same result as unpacking @@ -242,8 +231,7 @@ linux_newfstat(struct thread *td, struct linux_newfstat_args *args) struct stat buf; int error; - error = kern_fstat(td, args->fd, &buf); - translate_fd_major_minor(td, args->fd, &buf); + error = linux_kern_fstat(td, args->fd, &buf); if (!error) error = newstat_copyout(&buf, args->buf); @@ -634,8 +622,7 @@ linux_fstat64(struct thread *td, struct linux_fstat64_args *args) struct stat buf; int error; - error = kern_fstat(td, args->fd, &buf); - translate_fd_major_minor(td, args->fd, &buf); + error = linux_kern_fstat(td, args->fd, &buf); if (!error) error = stat64_copyout(&buf, args->statbuf);