The member 'e_ehsize' that holds the ELF header size is compared with the elfhdr struct size. If not equal, goes out. If 'e_phoff' holds 0 the object has no program header table, so goes out. Ensures the file being loaded has the correct data encoding, checking 'e_ident[EI_DATA]' against 'ELF_DATA'. Besides the checks being in accordance with the ELF Specifications, they increase the binary consistency reducing the use of malformed ones. Signed-off-by: Geyslan G. Bem <geyslan@xxxxxxxxx> --- fs/binfmt_elf.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 571a423..326ca39 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -603,14 +603,20 @@ static int load_elf_binary(struct linux_binprm *bprm) if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0) goto out; + if (loc->elf_ex.e_ehsize != sizeof(struct elfhdr)) + goto out; if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN) goto out; if (!elf_check_arch(&loc->elf_ex)) goto out; + if (loc->elf_ex.e_ident[EI_DATA] != ELF_DATA) + goto out; if (!bprm->file->f_op->mmap) goto out; /* Now read in all of the header information */ + if (loc->elf_ex.e_phoff == 0) + goto out; if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr)) goto out; if (loc->elf_ex.e_phnum < 1 || -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
