| From bce5070d1aada88154b811a08eec1586ab24fce5 Mon Sep 17 00:00:00 2001 |
| From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> |
| Date: Mon, 27 Jan 2020 19:01:26 +0100 |
| Subject: [PATCH 055/116] virtiofsd: use /proc/self/fd/ O_PATH file descriptor |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com> |
| Message-id: <20200127190227.40942-52-dgilbert@redhat.com> |
| Patchwork-id: 93506 |
| O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 051/112] virtiofsd: use /proc/self/fd/ O_PATH file descriptor |
| Bugzilla: 1694164 |
| RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com> |
| RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com> |
| RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com> |
| |
| From: Stefan Hajnoczi <stefanha@redhat.com> |
| |
| Sandboxing will remove /proc from the mount namespace so we can no |
| longer build string paths into "/proc/self/fd/...". |
| |
| Keep an O_PATH file descriptor so we can still re-open fds via |
| /proc/self/fd. |
| |
| Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> |
| Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> |
| Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> |
| (cherry picked from commit 9f59d175e2ca96f0b87f534dba69ea547dd35945) |
| Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com> |
| |
| tools/virtiofsd/passthrough_ll.c | 130 +++++++++++++++++++++++++++++++-------- |
| 1 file changed, 103 insertions(+), 27 deletions(-) |
| |
| diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c |
| index e3d65c3..e2e2211 100644 |
| |
| |
| @@ -110,6 +110,9 @@ struct lo_data { |
| struct lo_map ino_map; /* protected by lo->mutex */ |
| struct lo_map dirp_map; /* protected by lo->mutex */ |
| struct lo_map fd_map; /* protected by lo->mutex */ |
| + |
| + /* An O_PATH file descriptor to /proc/self/fd/ */ |
| + int proc_self_fd; |
| }; |
| |
| static const struct fuse_opt lo_opts[] = { |
| @@ -379,9 +382,9 @@ static int lo_parent_and_name(struct lo_data *lo, struct lo_inode *inode, |
| int res; |
| |
| retry: |
| - sprintf(procname, "/proc/self/fd/%i", inode->fd); |
| + sprintf(procname, "%i", inode->fd); |
| |
| - res = readlink(procname, path, PATH_MAX); |
| + res = readlinkat(lo->proc_self_fd, procname, path, PATH_MAX); |
| if (res < 0) { |
| fuse_log(FUSE_LOG_WARNING, "%s: readlink failed: %m\n", __func__); |
| goto fail_noretry; |
| @@ -477,9 +480,9 @@ static int utimensat_empty(struct lo_data *lo, struct lo_inode *inode, |
| } |
| return res; |
| } |
| - sprintf(path, "/proc/self/fd/%i", inode->fd); |
| + sprintf(path, "%i", inode->fd); |
| |
| - return utimensat(AT_FDCWD, path, tv, 0); |
| + return utimensat(lo->proc_self_fd, path, tv, 0); |
| |
| fallback: |
| res = lo_parent_and_name(lo, inode, path, &parent); |
| @@ -535,8 +538,8 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, |
| if (fi) { |
| res = fchmod(fd, attr->st_mode); |
| } else { |
| - sprintf(procname, "/proc/self/fd/%i", ifd); |
| - res = chmod(procname, attr->st_mode); |
| + sprintf(procname, "%i", ifd); |
| + res = fchmodat(lo->proc_self_fd, procname, attr->st_mode, 0); |
| } |
| if (res == -1) { |
| goto out_err; |
| @@ -552,11 +555,23 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, |
| } |
| } |
| if (valid & FUSE_SET_ATTR_SIZE) { |
| + int truncfd; |
| + |
| if (fi) { |
| - res = ftruncate(fd, attr->st_size); |
| + truncfd = fd; |
| } else { |
| - sprintf(procname, "/proc/self/fd/%i", ifd); |
| - res = truncate(procname, attr->st_size); |
| + sprintf(procname, "%i", ifd); |
| + truncfd = openat(lo->proc_self_fd, procname, O_RDWR); |
| + if (truncfd < 0) { |
| + goto out_err; |
| + } |
| + } |
| + |
| + res = ftruncate(truncfd, attr->st_size); |
| + if (!fi) { |
| + saverr = errno; |
| + close(truncfd); |
| + errno = saverr; |
| } |
| if (res == -1) { |
| goto out_err; |
| @@ -874,9 +889,9 @@ static int linkat_empty_nofollow(struct lo_data *lo, struct lo_inode *inode, |
| return res; |
| } |
| |
| - sprintf(path, "/proc/self/fd/%i", inode->fd); |
| + sprintf(path, "%i", inode->fd); |
| |
| - return linkat(AT_FDCWD, path, dfd, name, AT_SYMLINK_FOLLOW); |
| + return linkat(lo->proc_self_fd, path, dfd, name, AT_SYMLINK_FOLLOW); |
| |
| fallback: |
| res = lo_parent_and_name(lo, inode, path, &parent); |
| @@ -1404,8 +1419,8 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi) |
| fi->flags &= ~O_APPEND; |
| } |
| |
| - sprintf(buf, "/proc/self/fd/%i", lo_fd(req, ino)); |
| - fd = open(buf, fi->flags & ~O_NOFOLLOW); |
| + sprintf(buf, "%i", lo_fd(req, ino)); |
| + fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW); |
| if (fd == -1) { |
| return (void)fuse_reply_err(req, errno); |
| } |
| @@ -1458,7 +1473,6 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, |
| struct fuse_file_info *fi) |
| { |
| int res; |
| - (void)ino; |
| int fd; |
| char *buf; |
| |
| @@ -1466,12 +1480,14 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync, |
| (void *)fi); |
| |
| if (!fi) { |
| - res = asprintf(&buf, "/proc/self/fd/%i", lo_fd(req, ino)); |
| + struct lo_data *lo = lo_data(req); |
| + |
| + res = asprintf(&buf, "%i", lo_fd(req, ino)); |
| if (res == -1) { |
| return (void)fuse_reply_err(req, errno); |
| } |
| |
| - fd = open(buf, O_RDWR); |
| + fd = openat(lo->proc_self_fd, buf, O_RDWR); |
| free(buf); |
| if (fd == -1) { |
| return (void)fuse_reply_err(req, errno); |
| @@ -1587,11 +1603,13 @@ static void lo_flock(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi, |
| static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| size_t size) |
| { |
| + struct lo_data *lo = lo_data(req); |
| char *value = NULL; |
| char procname[64]; |
| struct lo_inode *inode; |
| ssize_t ret; |
| int saverr; |
| + int fd = -1; |
| |
| inode = lo_inode(req, ino); |
| if (!inode) { |
| @@ -1616,7 +1634,11 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| goto out; |
| } |
| |
| - sprintf(procname, "/proc/self/fd/%i", inode->fd); |
| + sprintf(procname, "%i", inode->fd); |
| + fd = openat(lo->proc_self_fd, procname, O_RDONLY); |
| + if (fd < 0) { |
| + goto out_err; |
| + } |
| |
| if (size) { |
| value = malloc(size); |
| @@ -1624,7 +1646,7 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| goto out_err; |
| } |
| |
| - ret = getxattr(procname, name, value, size); |
| + ret = fgetxattr(fd, name, value, size); |
| if (ret == -1) { |
| goto out_err; |
| } |
| @@ -1635,7 +1657,7 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| |
| fuse_reply_buf(req, value, ret); |
| } else { |
| - ret = getxattr(procname, name, NULL, 0); |
| + ret = fgetxattr(fd, name, NULL, 0); |
| if (ret == -1) { |
| goto out_err; |
| } |
| @@ -1644,6 +1666,10 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| } |
| out_free: |
| free(value); |
| + |
| + if (fd >= 0) { |
| + close(fd); |
| + } |
| return; |
| |
| out_err: |
| @@ -1655,11 +1681,13 @@ out: |
| |
| static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) |
| { |
| + struct lo_data *lo = lo_data(req); |
| char *value = NULL; |
| char procname[64]; |
| struct lo_inode *inode; |
| ssize_t ret; |
| int saverr; |
| + int fd = -1; |
| |
| inode = lo_inode(req, ino); |
| if (!inode) { |
| @@ -1683,7 +1711,11 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) |
| goto out; |
| } |
| |
| - sprintf(procname, "/proc/self/fd/%i", inode->fd); |
| + sprintf(procname, "%i", inode->fd); |
| + fd = openat(lo->proc_self_fd, procname, O_RDONLY); |
| + if (fd < 0) { |
| + goto out_err; |
| + } |
| |
| if (size) { |
| value = malloc(size); |
| @@ -1691,7 +1723,7 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) |
| goto out_err; |
| } |
| |
| - ret = listxattr(procname, value, size); |
| + ret = flistxattr(fd, value, size); |
| if (ret == -1) { |
| goto out_err; |
| } |
| @@ -1702,7 +1734,7 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) |
| |
| fuse_reply_buf(req, value, ret); |
| } else { |
| - ret = listxattr(procname, NULL, 0); |
| + ret = flistxattr(fd, NULL, 0); |
| if (ret == -1) { |
| goto out_err; |
| } |
| @@ -1711,6 +1743,10 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) |
| } |
| out_free: |
| free(value); |
| + |
| + if (fd >= 0) { |
| + close(fd); |
| + } |
| return; |
| |
| out_err: |
| @@ -1724,9 +1760,11 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| const char *value, size_t size, int flags) |
| { |
| char procname[64]; |
| + struct lo_data *lo = lo_data(req); |
| struct lo_inode *inode; |
| ssize_t ret; |
| int saverr; |
| + int fd = -1; |
| |
| inode = lo_inode(req, ino); |
| if (!inode) { |
| @@ -1751,21 +1789,31 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name, |
| goto out; |
| } |
| |
| - sprintf(procname, "/proc/self/fd/%i", inode->fd); |
| + sprintf(procname, "%i", inode->fd); |
| + fd = openat(lo->proc_self_fd, procname, O_RDWR); |
| + if (fd < 0) { |
| + saverr = errno; |
| + goto out; |
| + } |
| |
| - ret = setxattr(procname, name, value, size, flags); |
| + ret = fsetxattr(fd, name, value, size, flags); |
| saverr = ret == -1 ? errno : 0; |
| |
| out: |
| + if (fd >= 0) { |
| + close(fd); |
| + } |
| fuse_reply_err(req, saverr); |
| } |
| |
| static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name) |
| { |
| char procname[64]; |
| + struct lo_data *lo = lo_data(req); |
| struct lo_inode *inode; |
| ssize_t ret; |
| int saverr; |
| + int fd = -1; |
| |
| inode = lo_inode(req, ino); |
| if (!inode) { |
| @@ -1789,12 +1837,20 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name) |
| goto out; |
| } |
| |
| - sprintf(procname, "/proc/self/fd/%i", inode->fd); |
| + sprintf(procname, "%i", inode->fd); |
| + fd = openat(lo->proc_self_fd, procname, O_RDWR); |
| + if (fd < 0) { |
| + saverr = errno; |
| + goto out; |
| + } |
| |
| - ret = removexattr(procname, name); |
| + ret = fremovexattr(fd, name); |
| saverr = ret == -1 ? errno : 0; |
| |
| out: |
| + if (fd >= 0) { |
| + close(fd); |
| + } |
| fuse_reply_err(req, saverr); |
| } |
| |
| @@ -1887,12 +1943,25 @@ static void print_capabilities(void) |
| printf("}\n"); |
| } |
| |
| +static void setup_proc_self_fd(struct lo_data *lo) |
| +{ |
| + lo->proc_self_fd = open("/proc/self/fd", O_PATH); |
| + if (lo->proc_self_fd == -1) { |
| + fuse_log(FUSE_LOG_ERR, "open(/proc/self/fd, O_PATH): %m\n"); |
| + exit(1); |
| + } |
| +} |
| + |
| int main(int argc, char *argv[]) |
| { |
| struct fuse_args args = FUSE_ARGS_INIT(argc, argv); |
| struct fuse_session *se; |
| struct fuse_cmdline_opts opts; |
| - struct lo_data lo = { .debug = 0, .writeback = 0 }; |
| + struct lo_data lo = { |
| + .debug = 0, |
| + .writeback = 0, |
| + .proc_self_fd = -1, |
| + }; |
| struct lo_map_elem *root_elem; |
| int ret = -1; |
| |
| @@ -2003,6 +2072,9 @@ int main(int argc, char *argv[]) |
| |
| fuse_daemonize(opts.foreground); |
| |
| + /* Must be after daemonize to get the right /proc/self/fd */ |
| + setup_proc_self_fd(&lo); |
| + |
| /* Block until ctrl+c or fusermount -u */ |
| ret = virtio_loop(se); |
| |
| @@ -2018,6 +2090,10 @@ err_out1: |
| lo_map_destroy(&lo.dirp_map); |
| lo_map_destroy(&lo.ino_map); |
| |
| + if (lo.proc_self_fd >= 0) { |
| + close(lo.proc_self_fd); |
| + } |
| + |
| if (lo.root.fd >= 0) { |
| close(lo.root.fd); |
| } |
| -- |
| 1.8.3.1 |
| |