From e53a97a5b8bd88fa8657350a2393207e3be0e053 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Sat, 10 Jul 2021 20:00:37 -0500 Subject: [PATCH] file reference counts can get corrupted Callers of zfs_file_get and zfs_file_put can corrupt the reference counts for the file structure resulting in a panic or a soft lockup. When zfs send/recv runs, it will add a reference count to the open file, and begin to send or recv the stream. If the file descriptor is closed, then when dmu_recv_stream() or dmu_send() return we will call zfs_file_put to remove the reference we placed on the file structure. Unfortunately, because zfs_file_put() uses the file descriptor to lookup the file structure, it may end up finding that the file descriptor table no longer contains the file struct, thus leaking the file structure. Or it might end up finding a file descriptor for a different file and blindly updating its reference counts. Other failure modes probably exists. This change reworks the zfs_file_[get|put] interface to not rely on the file descriptor but instead pass the zfs_file_t pointer around. Reviewed-by: Matthew Ahrens Reviewed-by: Brian Behlendorf Reviewed-by: Mark Maybee Reviewed-by: Ryan Moeller Co-authored-by: Allan Jude Signed-off-by: George Wilson External-issue: DLPX-76119 Closes #12299 --- include/sys/fm/util.h | 5 +- include/sys/zfs_file.h | 6 ++- include/sys/zfs_ioctl.h | 2 +- include/sys/zfs_onexit.h | 4 +- lib/libzpool/kernel.c | 20 ++++---- module/os/freebsd/zfs/zfs_file_os.c | 19 +++----- module/os/linux/zfs/zfs_file_os.c | 28 +++--------- module/zfs/fm.c | 20 ++++---- module/zfs/zfs_ioctl.c | 71 ++++++++++++++--------------- module/zfs/zfs_onexit.c | 23 ++++++---- 10 files changed, 91 insertions(+), 107 deletions(-) diff --git a/include/sys/fm/util.h b/include/sys/fm/util.h index 56ba8798beb0..5fb6d1d6072b 100644 --- a/include/sys/fm/util.h +++ b/include/sys/fm/util.h @@ -31,6 +31,7 @@ extern "C" { #endif #include +#include /* * Shared user/kernel definitions for class length, error channel name, @@ -95,8 +96,8 @@ extern void fm_fini(void); extern void zfs_zevent_post_cb(nvlist_t *nvl, nvlist_t *detector); extern int zfs_zevent_post(nvlist_t *, nvlist_t *, zevent_cb_t *); extern void zfs_zevent_drain_all(int *); -extern int zfs_zevent_fd_hold(int, minor_t *, zfs_zevent_t **); -extern void zfs_zevent_fd_rele(int); +extern zfs_file_t *zfs_zevent_fd_hold(int, minor_t *, zfs_zevent_t **); +extern void zfs_zevent_fd_rele(zfs_file_t *); extern int zfs_zevent_next(zfs_zevent_t *, nvlist_t **, uint64_t *, uint64_t *); extern int zfs_zevent_wait(zfs_zevent_t *); extern int zfs_zevent_seek(zfs_zevent_t *, uint64_t); diff --git a/include/sys/zfs_file.h b/include/sys/zfs_file.h index d117933a6e4c..02cd1a6f041a 100644 --- a/include/sys/zfs_file.h +++ b/include/sys/zfs_file.h @@ -22,6 +22,8 @@ #ifndef _SYS_ZFS_FILE_H #define _SYS_ZFS_FILE_H +#include + #ifndef _KERNEL typedef struct zfs_file { int f_fd; @@ -55,8 +57,8 @@ int zfs_file_fallocate(zfs_file_t *fp, int mode, loff_t offset, loff_t len); loff_t zfs_file_off(zfs_file_t *fp); int zfs_file_unlink(const char *); -int zfs_file_get(int fd, zfs_file_t **fp); -void zfs_file_put(int fd); +zfs_file_t *zfs_file_get(int fd); +void zfs_file_put(zfs_file_t *fp); void *zfs_file_private(zfs_file_t *fp); #endif /* _SYS_ZFS_FILE_H */ diff --git a/include/sys/zfs_ioctl.h b/include/sys/zfs_ioctl.h index 8834c52990d0..1ca3f211b56d 100644 --- a/include/sys/zfs_ioctl.h +++ b/include/sys/zfs_ioctl.h @@ -566,7 +566,7 @@ typedef struct zfsdev_state { } zfsdev_state_t; extern void *zfsdev_get_state(minor_t minor, enum zfsdev_state_type which); -extern int zfsdev_getminor(int fd, minor_t *minorp); +extern int zfsdev_getminor(zfs_file_t *fp, minor_t *minorp); extern minor_t zfsdev_minor_alloc(void); extern uint_t zfs_fsyncer_key; diff --git a/include/sys/zfs_onexit.h b/include/sys/zfs_onexit.h index 0fab23ff849b..fd3030e3ac2d 100644 --- a/include/sys/zfs_onexit.h +++ b/include/sys/zfs_onexit.h @@ -51,8 +51,8 @@ extern void zfs_onexit_destroy(zfs_onexit_t *zo); #endif -extern int zfs_onexit_fd_hold(int fd, minor_t *minorp); -extern void zfs_onexit_fd_rele(int fd); +extern zfs_file_t *zfs_onexit_fd_hold(int fd, minor_t *minorp); +extern void zfs_onexit_fd_rele(zfs_file_t *); extern int zfs_onexit_add_cb(minor_t minor, void (*func)(void *), void *data, uint64_t *action_handle); diff --git a/lib/libzpool/kernel.c b/lib/libzpool/kernel.c index 09812decefcf..5f4740261f98 100644 --- a/lib/libzpool/kernel.c +++ b/lib/libzpool/kernel.c @@ -936,16 +936,16 @@ kmem_asprintf(const char *fmt, ...) } /* ARGSUSED */ -int +zfs_file_t * zfs_onexit_fd_hold(int fd, minor_t *minorp) { *minorp = 0; - return (0); + return (NULL); } /* ARGSUSED */ void -zfs_onexit_fd_rele(int fd) +zfs_onexit_fd_rele(zfs_file_t *fp) { } @@ -1355,28 +1355,26 @@ zfs_file_unlink(const char *path) * Get reference to file pointer * * fd - input file descriptor - * fpp - pointer to file pointer * - * Returns 0 on success EBADF on failure. + * Returns pointer to file struct or NULL. * Unsupported in user space. */ -int -zfs_file_get(int fd, zfs_file_t **fpp) +zfs_file_t * +zfs_file_get(int fd) { abort(); - return (EOPNOTSUPP); + return (NULL); } - /* * Drop reference to file pointer * - * fd - input file descriptor + * fp - pointer to file struct * * Unsupported in user space. */ void -zfs_file_put(int fd) +zfs_file_put(zfs_file_t *fp) { abort(); } diff --git a/module/os/freebsd/zfs/zfs_file_os.c b/module/os/freebsd/zfs/zfs_file_os.c index 908cff6810eb..a3d67aaa11ba 100644 --- a/module/os/freebsd/zfs/zfs_file_os.c +++ b/module/os/freebsd/zfs/zfs_file_os.c @@ -241,28 +241,21 @@ zfs_file_fsync(zfs_file_t *fp, int flags) return (zfs_vop_fsync(fp->f_vnode)); } -int -zfs_file_get(int fd, zfs_file_t **fpp) +zfs_file_t * +zfs_file_get(int fd) { struct file *fp; if (fget(curthread, fd, &cap_no_rights, &fp)) - return (SET_ERROR(EBADF)); + return (NULL); - *fpp = fp; - return (0); + return (fp); } void -zfs_file_put(int fd) +zfs_file_put(zfs_file_t *fp) { - struct file *fp; - - /* No CAP_ rights required, as we're only releasing. */ - if (fget(curthread, fd, &cap_no_rights, &fp) == 0) { - fdrop(fp, curthread); - fdrop(fp, curthread); - } + fdrop(fp, curthread); } loff_t diff --git a/module/os/linux/zfs/zfs_file_os.c b/module/os/linux/zfs/zfs_file_os.c index 35e647375d9d..e12f7c3ced43 100644 --- a/module/os/linux/zfs/zfs_file_os.c +++ b/module/os/linux/zfs/zfs_file_os.c @@ -407,36 +407,22 @@ zfs_file_unlink(const char *path) * Get reference to file pointer * * fd - input file descriptor - * fpp - pointer to file pointer * - * Returns 0 on success EBADF on failure. + * Returns pointer to file struct or NULL */ -int -zfs_file_get(int fd, zfs_file_t **fpp) +zfs_file_t * +zfs_file_get(int fd) { - zfs_file_t *fp; - - fp = fget(fd); - if (fp == NULL) - return (EBADF); - - *fpp = fp; - - return (0); + return (fget(fd)); } /* * Drop reference to file pointer * - * fd - input file descriptor + * fp - input file struct pointer */ void -zfs_file_put(int fd) +zfs_file_put(zfs_file_t *fp) { - struct file *fp; - - if ((fp = fget(fd)) != NULL) { - fput(fp); - fput(fp); - } + fput(fp); } diff --git a/module/zfs/fm.c b/module/zfs/fm.c index dff7d8ece4be..b8a1c7c8a5ca 100644 --- a/module/zfs/fm.c +++ b/module/zfs/fm.c @@ -278,25 +278,29 @@ zfs_zevent_minor_to_state(minor_t minor, zfs_zevent_t **ze) return (0); } -int +zfs_file_t * zfs_zevent_fd_hold(int fd, minor_t *minorp, zfs_zevent_t **ze) { - int error; + zfs_file_t *fp = zfs_file_get(fd); + if (fp == NULL) + return (NULL); - error = zfsdev_getminor(fd, minorp); + int error = zfsdev_getminor(fp, minorp); if (error == 0) error = zfs_zevent_minor_to_state(*minorp, ze); - if (error) - zfs_zevent_fd_rele(fd); + if (error) { + zfs_zevent_fd_rele(fp); + fp = NULL; + } - return (error); + return (fp); } void -zfs_zevent_fd_rele(int fd) +zfs_zevent_fd_rele(zfs_file_t *fp) { - zfs_file_put(fd); + zfs_file_put(fp); } /* diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c index b0eee81bebe9..3336bb783251 100644 --- a/module/zfs/zfs_ioctl.c +++ b/module/zfs/zfs_ioctl.c @@ -4861,8 +4861,8 @@ zfs_ioc_recv_impl(char *tofs, char *tosnap, char *origin, nvlist_t *recvprops, *errors = fnvlist_alloc(); off = 0; - if ((error = zfs_file_get(input_fd, &input_fp))) - return (error); + if ((input_fp = zfs_file_get(input_fd)) == NULL) + return (SET_ERROR(EBADF)); noff = off = zfs_file_off(input_fp); error = dmu_recv_begin(tofs, tosnap, begin_record, force, @@ -5142,7 +5142,7 @@ zfs_ioc_recv_impl(char *tofs, char *tosnap, char *origin, nvlist_t *recvprops, nvlist_free(inheritprops); } out: - zfs_file_put(input_fd); + zfs_file_put(input_fp); nvlist_free(origrecvd); nvlist_free(origprops); @@ -5472,8 +5472,8 @@ zfs_ioc_send(zfs_cmd_t *zc) zfs_file_t *fp; dmu_send_outparams_t out = {0}; - if ((error = zfs_file_get(zc->zc_cookie, &fp))) - return (error); + if ((fp = zfs_file_get(zc->zc_cookie)) == NULL) + return (SET_ERROR(EBADF)); off = zfs_file_off(fp); out.dso_outfunc = dump_bytes; @@ -5483,7 +5483,7 @@ zfs_ioc_send(zfs_cmd_t *zc) zc->zc_fromobj, embedok, large_block_ok, compressok, rawok, savedok, zc->zc_cookie, &off, &out); - zfs_file_put(zc->zc_cookie); + zfs_file_put(fp); } return (error); } @@ -6047,25 +6047,24 @@ zfs_ioc_tmp_snapshot(zfs_cmd_t *zc) { char *snap_name; char *hold_name; - int error; minor_t minor; - error = zfs_onexit_fd_hold(zc->zc_cleanup_fd, &minor); - if (error != 0) - return (error); + zfs_file_t *fp = zfs_onexit_fd_hold(zc->zc_cleanup_fd, &minor); + if (fp == NULL) + return (SET_ERROR(EBADF)); snap_name = kmem_asprintf("%s-%016llx", zc->zc_value, (u_longlong_t)ddi_get_lbolt64()); hold_name = kmem_asprintf("%%%s", zc->zc_value); - error = dsl_dataset_snapshot_tmp(zc->zc_name, snap_name, minor, + int error = dsl_dataset_snapshot_tmp(zc->zc_name, snap_name, minor, hold_name); if (error == 0) (void) strlcpy(zc->zc_value, snap_name, sizeof (zc->zc_value)); kmem_strfree(snap_name); kmem_strfree(hold_name); - zfs_onexit_fd_rele(zc->zc_cleanup_fd); + zfs_onexit_fd_rele(fp); return (error); } @@ -6085,13 +6084,13 @@ zfs_ioc_diff(zfs_cmd_t *zc) offset_t off; int error; - if ((error = zfs_file_get(zc->zc_cookie, &fp))) - return (error); + if ((fp = zfs_file_get(zc->zc_cookie)) == NULL) + return (SET_ERROR(EBADF)); off = zfs_file_off(fp); error = dmu_diff(zc->zc_name, zc->zc_value, fp, &off); - zfs_file_put(zc->zc_cookie); + zfs_file_put(fp); return (error); } @@ -6127,6 +6126,7 @@ zfs_ioc_hold(const char *pool, nvlist_t *args, nvlist_t *errlist) int cleanup_fd = -1; int error; minor_t minor = 0; + zfs_file_t *fp = NULL; holds = fnvlist_lookup_nvlist(args, "holds"); @@ -6144,14 +6144,16 @@ zfs_ioc_hold(const char *pool, nvlist_t *args, nvlist_t *errlist) } if (nvlist_lookup_int32(args, "cleanup_fd", &cleanup_fd) == 0) { - error = zfs_onexit_fd_hold(cleanup_fd, &minor); - if (error != 0) - return (SET_ERROR(error)); + fp = zfs_onexit_fd_hold(cleanup_fd, &minor); + if (fp == NULL) + return (SET_ERROR(EBADF)); } error = dsl_dataset_user_hold(holds, minor, errlist); - if (minor != 0) - zfs_onexit_fd_rele(cleanup_fd); + if (fp != NULL) { + ASSERT3U(minor, !=, 0); + zfs_onexit_fd_rele(fp); + } return (SET_ERROR(error)); } @@ -6214,9 +6216,9 @@ zfs_ioc_events_next(zfs_cmd_t *zc) uint64_t dropped = 0; int error; - error = zfs_zevent_fd_hold(zc->zc_cleanup_fd, &minor, &ze); - if (error != 0) - return (error); + zfs_file_t *fp = zfs_zevent_fd_hold(zc->zc_cleanup_fd, &minor, &ze); + if (fp == NULL) + return (SET_ERROR(EBADF)); do { error = zfs_zevent_next(ze, &event, @@ -6238,7 +6240,7 @@ zfs_ioc_events_next(zfs_cmd_t *zc) break; } while (1); - zfs_zevent_fd_rele(zc->zc_cleanup_fd); + zfs_zevent_fd_rele(fp); return (error); } @@ -6270,12 +6272,12 @@ zfs_ioc_events_seek(zfs_cmd_t *zc) minor_t minor; int error; - error = zfs_zevent_fd_hold(zc->zc_cleanup_fd, &minor, &ze); - if (error != 0) - return (error); + zfs_file_t *fp = zfs_zevent_fd_hold(zc->zc_cleanup_fd, &minor, &ze); + if (fp == NULL) + return (SET_ERROR(EBADF)); error = zfs_zevent_seek(ze, zc->zc_guid); - zfs_zevent_fd_rele(zc->zc_cleanup_fd); + zfs_zevent_fd_rele(fp); return (error); } @@ -6459,8 +6461,8 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl) (void) nvlist_lookup_string(innvl, "redactbook", &redactbook); - if ((error = zfs_file_get(fd, &fp))) - return (error); + if ((fp = zfs_file_get(fd)) == NULL) + return (SET_ERROR(EBADF)); off = zfs_file_off(fp); @@ -6472,7 +6474,7 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl) compressok, rawok, savedok, resumeobj, resumeoff, redactbook, fd, &off, &out); - zfs_file_put(fd); + zfs_file_put(fp); return (error); } @@ -7345,17 +7347,12 @@ pool_status_check(const char *name, zfs_ioc_namecheck_t type, } int -zfsdev_getminor(int fd, minor_t *minorp) +zfsdev_getminor(zfs_file_t *fp, minor_t *minorp) { zfsdev_state_t *zs, *fpd; - zfs_file_t *fp; - int rc; ASSERT(!MUTEX_HELD(&zfsdev_state_lock)); - if ((rc = zfs_file_get(fd, &fp))) - return (rc); - fpd = zfs_file_private(fp); if (fpd == NULL) return (SET_ERROR(EBADF)); diff --git a/module/zfs/zfs_onexit.c b/module/zfs/zfs_onexit.c index 2a1332e715ee..7c56dd9c97f5 100644 --- a/module/zfs/zfs_onexit.c +++ b/module/zfs/zfs_onexit.c @@ -107,30 +107,33 @@ zfs_onexit_destroy(zfs_onexit_t *zo) * of this function must call zfs_onexit_fd_rele() when they're finished * using the minor number. */ -int +zfs_file_t * zfs_onexit_fd_hold(int fd, minor_t *minorp) { zfs_onexit_t *zo = NULL; - int error; - error = zfsdev_getminor(fd, minorp); + zfs_file_t *fp = zfs_file_get(fd); + if (fp == NULL) + return (NULL); + + int error = zfsdev_getminor(fp, minorp); if (error) { - zfs_onexit_fd_rele(fd); - return (error); + zfs_onexit_fd_rele(fp); + return (NULL); } zo = zfsdev_get_state(*minorp, ZST_ONEXIT); if (zo == NULL) { - zfs_onexit_fd_rele(fd); - return (SET_ERROR(EBADF)); + zfs_onexit_fd_rele(fp); + return (NULL); } - return (0); + return (fp); } void -zfs_onexit_fd_rele(int fd) +zfs_onexit_fd_rele(zfs_file_t *fp) { - zfs_file_put(fd); + zfs_file_put(fp); } static int