From e63bf1b13b3a7ac610c238cc19041381e890900f Mon Sep 17 00:00:00 2001 From: Eugeniu Rosca Date: Thu, 14 Mar 2019 18:31:39 +0100 Subject: common: image-android-dt: Fix out-of-bounds access Currently, 'dtimg' allows users to check indexes equal to dt_entry_count [1]. Forbid that [2]. [1] Behavior w/o the patch: => ext2load mmc 0:1 0x48000000 dtb.img 105695 bytes read in 5 ms (20.2 MiB/s) => dtimg dump 0x48000000 dt_table_header: magic = d7b7ab1e total_size = 105695 header_size = 32 dt_entry_size = 32 dt_entry_count = 2 dt_entries_offset = 32 page_size = 4096 version = 0 dt_table_entry[0]: dt_size = 105599 dt_offset = 96 id = 0b779520 rev = 00000000 custom[0] = 00000000 custom[1] = 00000000 custom[2] = 00000000 custom[3] = 00000000 (FDT)size = 105599 (FDT)compatible = shimafuji,kingfisher dt_table_entry[1]: dt_size = 105599 dt_offset = 96 id = 0b779530 rev = 00000000 custom[0] = 00000000 custom[1] = 00000000 custom[2] = 00000000 custom[3] = 00000000 (FDT)size = 105599 (FDT)compatible = shimafuji,kingfisher => dtimg size 0x48000000 0 z; print z z=19c7f => dtimg size 0x48000000 1 z; print z z=19c7f => dtimg size 0x48000000 2 z; print z z=d00dfeed => dtimg size 0x48000000 3 z Error: index > dt_entry_count (3 > 2) [2] Behavior with the patch: => dtimg size 0x48000000 0 z; print z z=19c7f => dtimg size 0x48000000 1 z; print z z=19c7f => dtimg size 0x48000000 2 z Error: index >= dt_entry_count (2 >= 2) Fixes: c04473345712 ("common: Add support for Android DT image") Signed-off-by: Eugeniu Rosca --- common/image-android-dt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/common/image-android-dt.c b/common/image-android-dt.c index c0683ee70f..6916826179 100644 --- a/common/image-android-dt.c +++ b/common/image-android-dt.c @@ -53,8 +53,8 @@ bool android_dt_get_fdt_by_index(ulong hdr_addr, u32 index, ulong *addr, entry_size = fdt32_to_cpu(hdr->dt_entry_size); unmap_sysmem(hdr); - if (index > entry_count) { - printf("Error: index > dt_entry_count (%u > %u)\n", index, + if (index >= entry_count) { + printf("Error: index >= dt_entry_count (%u >= %u)\n", index, entry_count); return false; } -- cgit v1.2.1