From 7a6c12fd6a756af5a2f664c0a6a292d22fbb2487 Mon Sep 17 00:00:00 2001 From: Allan Jude Date: Tue, 25 Aug 2020 14:04:20 -0400 Subject: [PATCH] Don't assert on nvlists larger than SPA_MAXBLOCKSIZE Originally we asserted that all reads are less than SPA_MAXBLOCKSIZE However, nvlists are not ZFS records, and are not limited to SPA_MAXBLOCKSIZE. Add a new environment variable, ZFS_SENDRECV_MAX_NVLIST, to allow the user to specify the maximum size of the nvlist that can be sent or received. Default value: 4 * SPA_MAXBLOCKSIZE (64 MB) Modify libzfs send routines to return a useful error if the send stream will generate an nvlist that is beyond the maximum size. Modify libzfs recv routines to add an explicit error message if the nvlist is too large, rather than abort()ing. Move the change the assert() to only trigger on data records Reviewed-by: Paul Dagnelie Reviewed-by: Kjeld Schouten Reviewed-by: Brian Behlendorf Reviewed-by: Matthew Ahrens Signed-off-by: Allan Jude Closes #9616 --- include/libzfs_impl.h | 1 + lib/libzfs/libzfs_sendrecv.c | 35 +++++++++++++++++++++++++++++++++-- lib/libzfs/libzfs_util.c | 10 ++++++++++ 3 files changed, 44 insertions(+), 2 deletions(-) diff --git a/include/libzfs_impl.h b/include/libzfs_impl.h index 0f11167976..26e0429647 100644 --- a/include/libzfs_impl.h +++ b/include/libzfs_impl.h @@ -71,6 +71,7 @@ struct libzfs_handle { char libzfs_chassis_id[256]; boolean_t libzfs_prop_debug; regex_t libzfs_urire; + uint64_t libzfs_max_nvlist; }; struct zfs_handle { diff --git a/lib/libzfs/libzfs_sendrecv.c b/lib/libzfs/libzfs_sendrecv.c index f1524c384f..e5af6453b0 100644 --- a/lib/libzfs/libzfs_sendrecv.c +++ b/lib/libzfs/libzfs_sendrecv.c @@ -610,6 +610,18 @@ send_iterate_fs(zfs_handle_t *zhp, void *arg) fnvlist_free(sd->snapprops); fnvlist_free(sd->snapholds); + /* Do not allow the size of the properties list to exceed the limit */ + if ((fnvlist_size(nvfs) + fnvlist_size(sd->fss)) > + zhp->zfs_hdl->libzfs_max_nvlist) { + (void) fprintf(stderr, dgettext(TEXT_DOMAIN, + "warning: cannot send %s@%s: the size of the list of " + "snapshots and properties is too large to be received " + "successfully.\n" + "Select a smaller number of snapshots to send.\n"), + zhp->zfs_name, sd->tosnap); + rv = EZFS_NOSPC; + goto out; + } /* add this fs to nvlist */ (void) snprintf(guidstring, sizeof (guidstring), "0x%llx", (longlong_t)guid); @@ -2015,6 +2027,21 @@ send_prelim_records(zfs_handle_t *zhp, const char *from, int fd, return (zfs_error(zhp->zfs_hdl, EZFS_BADBACKUP, errbuf)); } + /* + * Do not allow the size of the properties list to exceed + * the limit + */ + if ((fnvlist_size(fss) + fnvlist_size(hdrnv)) > + zhp->zfs_hdl->libzfs_max_nvlist) { + (void) snprintf(errbuf, sizeof (errbuf), + dgettext(TEXT_DOMAIN, "warning: cannot send '%s': " + "the size of the list of snapshots and properties " + "is too large to be received successfully.\n" + "Select a smaller number of snapshots to send.\n"), + zhp->zfs_name); + return (zfs_error(zhp->zfs_hdl, EZFS_NOSPC, + errbuf)); + } fnvlist_add_nvlist(hdrnv, "fss", fss); VERIFY0(nvlist_pack(hdrnv, &packbuf, &buflen, NV_ENCODE_XDR, 0)); @@ -2578,8 +2605,6 @@ recv_read(libzfs_handle_t *hdl, int fd, void *buf, int ilen, int rv; int len = ilen; - assert(ilen <= SPA_MAXBLOCKSIZE); - do { rv = read(fd, cp, len); cp += rv; @@ -2613,6 +2638,11 @@ recv_read_nvlist(libzfs_handle_t *hdl, int fd, int len, nvlist_t **nvp, if (buf == NULL) return (ENOMEM); + if (len > hdl->libzfs_max_nvlist) { + zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "nvlist too large")); + return (ENOMEM); + } + err = recv_read(hdl, fd, buf, len, byteswap, zc); if (err != 0) { free(buf); @@ -3783,6 +3813,7 @@ recv_skip(libzfs_handle_t *hdl, int fd, boolean_t byteswap) } payload_size = DRR_WRITE_PAYLOAD_SIZE(&drr->drr_u.drr_write); + assert(payload_size <= SPA_MAXBLOCKSIZE); (void) recv_read(hdl, fd, buf, payload_size, B_FALSE, NULL); break; diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c index c43c6bb1fe..301c8ddbab 100644 --- a/lib/libzfs/libzfs_util.c +++ b/lib/libzfs/libzfs_util.c @@ -1008,6 +1008,7 @@ libzfs_init(void) { libzfs_handle_t *hdl; int error; + char *env; error = libzfs_load_module(); if (error) { @@ -1055,6 +1056,15 @@ libzfs_init(void) if (getenv("ZFS_PROP_DEBUG") != NULL) { hdl->libzfs_prop_debug = B_TRUE; } + if ((env = getenv("ZFS_SENDRECV_MAX_NVLIST")) != NULL) { + if ((error = zfs_nicestrtonum(hdl, env, + &hdl->libzfs_max_nvlist))) { + errno = error; + return (NULL); + } + } else { + hdl->libzfs_max_nvlist = (SPA_MAXBLOCKSIZE * 4); + } /* * For testing, remove some settable properties and features