From 3781df9da23840e596d5e9e8493f22666802fe6c Mon Sep 17 00:00:00 2001 From: John Reiser Date: Fri, 11 Dec 2020 13:38:18 -0800 Subject: [PATCH] Check DT_REL/DT_RELA, DT_RELSZ/DT_RELASZ https://github.com/upx/upx/issues/421 modified: p_lx_elf.cpp --- src/p_lx_elf.cpp | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp index 182db192..3a4101cf 100644 --- a/src/p_lx_elf.cpp +++ b/src/p_lx_elf.cpp @@ -2222,8 +2222,20 @@ bool PackLinuxElf32::canPack() int z_rsz = dt_table[Elf32_Dyn::DT_RELSZ]; if (z_rel && z_rsz) { unsigned rel_off = get_te32(&dynseg[-1+ z_rel].d_val); + if ((unsigned)file_size <= rel_off) { + char msg[70]; snprintf(msg, sizeof(msg), + "bad Elf32_Dynamic[DT_REL] %#x\n", + rel_off); + throwCantPack(msg); + } Elf32_Rel *rp = (Elf32_Rel *)&file_image[rel_off]; unsigned relsz = get_te32(&dynseg[-1+ z_rsz].d_val); + if ((unsigned)file_size <= relsz) { + char msg[70]; snprintf(msg, sizeof(msg), + "bad Elf32_Dynamic[DT_RELSZ] %#x\n", + relsz); + throwCantPack(msg); + } Elf32_Rel *last = (Elf32_Rel *)(relsz + (char *)rp); for (; rp < last; ++rp) { unsigned r_va = get_te32(&rp->r_offset); @@ -2562,14 +2574,26 @@ PackLinuxElf64::canPack() int z_rel = dt_table[Elf64_Dyn::DT_RELA]; int z_rsz = dt_table[Elf64_Dyn::DT_RELASZ]; if (z_rel && z_rsz) { - unsigned rel_off = get_te64(&dynseg[-1+ z_rel].d_val); + upx_uint64_t rel_off = get_te64(&dynseg[-1+ z_rel].d_val); + if ((u64_t)file_size <= rel_off) { + char msg[70]; snprintf(msg, sizeof(msg), + "bad Elf64_Dynamic[DT_RELA] %#llx\n", + rel_off); + throwCantPack(msg); + } Elf64_Rela *rp = (Elf64_Rela *)&file_image[rel_off]; - unsigned relsz = get_te64(&dynseg[-1+ z_rsz].d_val); + upx_uint64_t relsz = get_te64(&dynseg[-1+ z_rsz].d_val); + if ((u64_t)file_size <= relsz) { + char msg[70]; snprintf(msg, sizeof(msg), + "bad Elf64_Dynamic[DT_RELASZ] %#llx\n", + relsz); + throwCantPack(msg); + } Elf64_Rela *last = (Elf64_Rela *)(relsz + (char *)rp); for (; rp < last; ++rp) { - unsigned r_va = get_te64(&rp->r_offset); + upx_uint64_t r_va = get_te64(&rp->r_offset); if (r_va == user_init_ava) { // found the Elf64_Rela - unsigned r_info = get_te64(&rp->r_info); + upx_uint64_t r_info = get_te64(&rp->r_info); unsigned r_type = ELF64_R_TYPE(r_info); if (Elf64_Ehdr::EM_AARCH64 == e_machine && R_AARCH64_RELATIVE == r_type) { @@ -2581,7 +2605,7 @@ PackLinuxElf64::canPack() } else { char msg[50]; snprintf(msg, sizeof(msg), - "bad relocation %#x DT_INIT_ARRAY[0]", + "bad relocation %#llx DT_INIT_ARRAY[0]", r_info); throwCantPack(msg); }