git: 5be5d0d5cb26 - main - geom_part: Check number of GPT entries and size of GPT entry
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Date: Tue, 18 Oct 2022 15:19:38 UTC
The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=5be5d0d5cb2657d7668f4ca0f8543198cf8d759b commit 5be5d0d5cb2657d7668f4ca0f8543198cf8d759b Author: Zhenlei Huang <zlei.huang@gmail.com> AuthorDate: 2022-10-18 15:03:02 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2022-10-18 15:03:02 +0000 geom_part: Check number of GPT entries and size of GPT entry Current specification does not have upper limit of the number of partition entries and the size of partition entry. In 799eac8c3df597179bbb3b078362f3ff03993a1a Andrey V. Elsukov introduced a limit maximum number of GPT entries to 4k, but that is for write routine (gpart create) only. When attaching disks that have large number of GPT entries exceeding the limit, or disks with large size of partition entry, it is still possible to exhaust kernel memory. 1. Reuse the limit of the maximum number of partition entries. 2. Limit the maximum size of GPT entry to 1k. In current specification (2.10) the size of GPT entry is 128 * 2^n while n >= 0, and the size - 128 is reserved. 1k should be sufficient enough for foreseen future. PR: 266548 Discussed with: imp Reviewed by: markj MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D36717 --- sys/geom/part/g_part_gpt.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/sys/geom/part/g_part_gpt.c b/sys/geom/part/g_part_gpt.c index 0c472e5ebba6..cd04fe714fbe 100644 --- a/sys/geom/part/g_part_gpt.c +++ b/sys/geom/part/g_part_gpt.c @@ -85,6 +85,7 @@ enum gpt_state { GPT_STATE_MISSING, /* No signature found. */ GPT_STATE_CORRUPT, /* Checksum mismatch. */ GPT_STATE_INVALID, /* Nonconformant/invalid. */ + GPT_STATE_UNSUPPORTED, /* Not supported. */ GPT_STATE_OK /* Perfectly fine. */ }; @@ -148,6 +149,8 @@ static kobj_method_t g_part_gpt_methods[] = { { 0, 0 } }; +#define MAXENTSIZE 1024 + static struct g_part_scheme g_part_gpt_scheme = { "GPT", g_part_gpt_methods, @@ -548,6 +551,11 @@ gpt_read_tbl(struct g_part_gpt_table *table, struct g_consumer *cp, if (hdr == NULL) return (NULL); + if (hdr->hdr_entries > g_part_gpt_scheme.gps_maxent || + hdr->hdr_entsz > MAXENTSIZE) { + table->state[elt] = GPT_STATE_UNSUPPORTED; + return (NULL); + } pp = cp->provider; table->lba[elt] = hdr->hdr_lba_table; @@ -961,10 +969,25 @@ g_part_gpt_read(struct g_part_table *basetable, struct g_consumer *cp) /* Fail if we haven't got any good tables at all. */ if (table->state[GPT_ELT_PRITBL] != GPT_STATE_OK && table->state[GPT_ELT_SECTBL] != GPT_STATE_OK) { - printf("GEOM: %s: corrupt or invalid GPT detected.\n", - pp->name); - printf("GEOM: %s: GPT rejected -- may not be recoverable.\n", - pp->name); + if (table->state[GPT_ELT_PRITBL] == GPT_STATE_UNSUPPORTED && + table->state[GPT_ELT_SECTBL] == GPT_STATE_UNSUPPORTED && + gpt_matched_hdrs(prihdr, sechdr)) { + printf("GEOM: %s: unsupported GPT detected.\n", + pp->name); + printf( + "GEOM: %s: number of GPT entries: %u, entry size: %uB.\n", + pp->name, prihdr->hdr_entries, prihdr->hdr_entsz); + printf( + "GEOM: %s: maximum supported number of GPT entries: %u, entry size: %uB.\n", + pp->name, g_part_gpt_scheme.gps_maxent, MAXENTSIZE); + printf("GEOM: %s: GPT rejected.\n", pp->name); + } else { + printf("GEOM: %s: corrupt or invalid GPT detected.\n", + pp->name); + printf( + "GEOM: %s: GPT rejected -- may not be recoverable.\n", + pp->name); + } if (prihdr != NULL) g_free(prihdr); if (pritbl != NULL)