From 043f757bb9cab39b6bee2e49550a99c66c122a60 Mon Sep 17 00:00:00 2001 From: Paul Emge Date: Tue, 14 Jan 2020 19:53:11 +0530 Subject: [PATCH] CVE-2019-13103: disk: stop infinite recursion in DOS Partitions part_get_info_extended and print_partition_extended can recurse infinitely while parsing a self-referential filesystem or one with a silly number of extended partitions. This patch adds a limit to the number of recursive partitions. Change-Id: Ibf1449684580a313869ce9961077c46a12a42d8c Signed-off-by: Paul Emge Signed-off-by: Karthick Shanmugham --- disk/part_dos.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/disk/part_dos.c b/disk/part_dos.c index 89263d38aa..d6da3c0ec5 100644 --- a/disk/part_dos.c +++ b/disk/part_dos.c @@ -24,6 +24,10 @@ #define DOS_PART_DEFAULT_SECTOR 512 +/* should this be configurable? It looks like it's not very common at all + * to use large numbers of partitions */ +#define MAX_EXT_PARTS 256 + /* Convert char[4] in little endian format to the host format integer */ static inline int le32_to_int(unsigned char *le32) @@ -109,6 +113,11 @@ static void print_partition_extended(block_dev_desc_t *dev_desc, dos_partition_t *pt; int i; + /* set a maximum recursion level */ + if (part_num > MAX_EXT_PARTS) { + printf("** Nested DOS partitions detected, stopping **\n"); + return; + } if (dev_desc->block_read(dev_desc->dev, ext_part_sector, 1, (ulong *) buffer) != 1) { printf ("** Can't read partition table on %d:%d **\n", dev_desc->dev, ext_part_sector); @@ -173,6 +182,12 @@ static int get_partition_info_extended (block_dev_desc_t *dev_desc, int ext_part int i; int dos_type; + /* set a maximum recursion level */ + if (part_num > MAX_EXT_PARTS) { + printf("** Nested DOS partitions detected, stopping **\n"); + return -1; + } + if (dev_desc->block_read (dev_desc->dev, ext_part_sector, 1, (ulong *) buffer) != 1) { printf ("** Can't read partition table on %d:%d **\n", dev_desc->dev, ext_part_sector);