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@@ -1,96 +0,0 @@ |
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From 3e0c2966dffb5dadb512a476ef4be3d0cc51c2be Mon Sep 17 00:00:00 2001 |
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From: Pierre Neidhardt <ambrevar@gmail.com> |
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Date: Sat, 16 Jun 2018 16:35:00 +0200 |
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Subject: [PATCH] Protect against bad crafted input |
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Also check for wrap-around when checking oversize involving e_shoff and e_shnum. |
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raised by https://github.com/upx/upx/pull/190 |
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modified: p_lx_elf.cpp |
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--- |
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src/p_lx_elf.cpp | 30 ++++++++++++++++++++++++++++++ |
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1 file changed, 30 insertions(+) |
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diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp |
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index 822a7652..41e805ee 100644 |
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--- a/src/p_lx_elf.cpp |
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+++ b/src/p_lx_elf.cpp |
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@@ -235,8 +235,17 @@ PackLinuxElf32::PackLinuxElf32help1(InputFile *f) |
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sz_phdrs = 0; |
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return; |
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} |
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+ if (0==e_phnum) throwCantUnpack("0==e_phnum"); |
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e_phoff = get_te32(&ehdri.e_phoff); |
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+ unsigned const last_Phdr = e_phoff + e_phnum * sizeof(Elf32_Phdr); |
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+ if (last_Phdr < e_phoff || (unsigned long)file_size < last_Phdr) { |
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+ throwCantUnpack("bad e_phoff"); |
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+ } |
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e_shoff = get_te32(&ehdri.e_shoff); |
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+ unsigned const last_Shdr = e_shoff + e_shnum * sizeof(Elf32_Shdr); |
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+ if (last_Shdr < e_shoff || (unsigned long)file_size < last_Shdr) { |
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+ throwCantUnpack("bad e_shoff"); |
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+ } |
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sz_phdrs = e_phnum * e_phentsize; |
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if (f && Elf32_Ehdr::ET_DYN!=e_type) { |
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@@ -599,8 +608,17 @@ PackLinuxElf64::PackLinuxElf64help1(InputFile *f) |
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sz_phdrs = 0; |
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return; |
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} |
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+ if (0==e_phnum) throwCantUnpack("0==e_phnum"); |
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e_phoff = get_te64(&ehdri.e_phoff); |
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+ upx_uint64_t const last_Phdr = e_phoff + e_phnum * sizeof(Elf64_Phdr); |
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+ if (last_Phdr < e_phoff || (unsigned long)file_size < last_Phdr) { |
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+ throwCantUnpack("bad e_phoff"); |
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+ } |
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e_shoff = get_te64(&ehdri.e_shoff); |
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+ upx_uint64_t const last_Shdr = e_shoff + e_shnum * sizeof(Elf64_Shdr); |
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+ if (last_Shdr < e_shoff || (unsigned long)file_size < last_Shdr) { |
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+ throwCantUnpack("bad e_shoff"); |
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+ } |
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sz_phdrs = e_phnum * e_phentsize; |
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if (f && Elf64_Ehdr::ET_DYN!=e_type) { |
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@@ -3763,6 +3781,9 @@ void PackLinuxElf64::pack4(OutputFile *fo, Filter &ft) |
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void PackLinuxElf64::unpack(OutputFile *fo) |
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{ |
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+ if (e_phoff != sizeof(Elf64_Ehdr)) {// Phdrs not contiguous with Ehdr |
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+ throwCantUnpack("bad e_phoff"); |
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+ } |
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unsigned const c_phnum = get_te16(&ehdri.e_phnum); |
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upx_uint64_t old_data_off = 0; |
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upx_uint64_t old_data_len = 0; |
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@@ -3828,6 +3849,9 @@ void PackLinuxElf64::unpack(OutputFile *fo) |
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unsigned total_out = 0; |
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unsigned c_adler = upx_adler32(NULL, 0); |
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unsigned u_adler = upx_adler32(NULL, 0); |
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+ if ((MAX_ELF_HDR - sizeof(Elf64_Ehdr))/sizeof(Elf64_Phdr) < u_phnum) { |
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+ throwCantUnpack("bad compressed e_phnum"); |
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+ } |
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// Packed ET_EXE has no PT_DYNAMIC. |
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// Packed ET_DYN has original PT_DYNAMIC for info needed by rtld. |
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@@ -4383,6 +4407,9 @@ Elf64_Sym const *PackLinuxElf64::elf_lookup(char const *name) const |
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void PackLinuxElf32::unpack(OutputFile *fo) |
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{ |
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+ if (e_phoff != sizeof(Elf32_Ehdr)) {// Phdrs not contiguous with Ehdr |
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+ throwCantUnpack("bad e_phoff"); |
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+ } |
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unsigned const c_phnum = get_te16(&ehdri.e_phnum); |
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unsigned old_data_off = 0; |
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unsigned old_data_len = 0; |
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@@ -4449,6 +4476,9 @@ void PackLinuxElf32::unpack(OutputFile *fo) |
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unsigned total_out = 0; |
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unsigned c_adler = upx_adler32(NULL, 0); |
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unsigned u_adler = upx_adler32(NULL, 0); |
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+ if ((MAX_ELF_HDR - sizeof(Elf32_Ehdr))/sizeof(Elf32_Phdr) < u_phnum) { |
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+ throwCantUnpack("bad compressed e_phnum"); |
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+ } |
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// Packed ET_EXE has no PT_DYNAMIC. |
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// Packed ET_DYN has original PT_DYNAMIC for info needed by rtld. |
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2.17.0 |
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