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Added some more checks to canPack(), throw an exception in case

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of crippled ELF headers.

committer: mfx <mfx> 977393134 +0000
This commit is contained in:
Markus F.X.J. Oberhumer 2000-12-21 10:05:34 +00:00
parent 42fe803a39
commit 06dc67da49
1 changed files with 40 additions and 22 deletions
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62
src/p_lx_elf.cpp
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@ -169,32 +169,50 @@ void PackLinuxI386elf::patchLoader()
bool PackLinuxI386elf::canPack()
{
unsigned char buf[512];
unsigned char buf[sizeof(Elf_LE32_Ehdr) + 16*sizeof(Elf_LE32_Phdr)];
exetype = 0;
// FIXME: add special checks for uncompresed "vmlinux" kernel
// FIXME: add checks for FreeBSD/... ELF executables
fi->readx(buf,512);
fi->seek(0,0);
if (0==memcmp(buf, "\x7f\x45\x4c\x46\x01\x01\x01", 7)) { // ELF 32-bit LSB
Elf_LE32_Ehdr const *const ehdr = (Elf_LE32_Ehdr const *)buf;
Elf_LE32_Phdr const *phdr = (Elf_LE32_Phdr const *)(ehdr->e_phoff +
(char const *)ehdr);
if (ehdr->e_phoff != sizeof(*ehdr)) {// Phdrs not contiguous with Ehdr
return false;
}
// The first PT_LOAD must cover the beginning of the file (0==p_offset).
for (unsigned j=0; j < ehdr->e_phnum; ++phdr, ++j) {
if (PT_LOAD==phdr->p_type) {
if (phdr->p_offset!=0) {
return false;
}
break;
}
}
exetype = 1;
return super::canPack();
fi->readx(buf, sizeof(buf));
fi->seek(0, SEEK_SET);
if (0 != memcmp(buf, "\x7f\x45\x4c\x46\x01\x01\x01", 7)) // ELF 32-bit LSB
return false;
// now check the ELF header
Elf_LE32_Ehdr const *const ehdr = (Elf_LE32_Ehdr const *)buf;
if (memcmp(buf+8, "FreeBSD", 7) == 0) // branded as FreeBSD
return false;
if (ehdr->e_type != 2) // executable
return false;
if (ehdr->e_machine != 3 && ehdr->e_machine != 6) // Intel 80[34]86
return false;
if (ehdr->e_version != 1) // version
return false;
if (ehdr->e_ehsize != sizeof(*ehdr)) {
throwCantPack("invalid Ehdr e_ehsize");
return false;
}
return false;
if (ehdr->e_phoff != sizeof(*ehdr)) {// Phdrs not contiguous with Ehdr
throwCantPack("non-contiguous Ehdr/Phdr");
return false;
}
// The first PT_LOAD must cover the beginning of the file (0==p_offset).
Elf_LE32_Phdr const *phdr = (Elf_LE32_Phdr const *)(buf + ehdr->e_phoff);
for (unsigned j=0; j < ehdr->e_phnum; ++phdr, ++j) {
if (j >= 16)
return false;
if (PT_LOAD==phdr->p_type) {
if (phdr->p_offset!=0)
return false;
exetype = 1;
break;
}
}
return super::canPack();
}