diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 975dd0dbc25274096d131e7bdf2c7b6e03cc5f0c..059da83112ff9ff36650924cef22654dede9d3b2 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -405,6 +406,26 @@ static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr) ELF_PAGESTART(cmds[first_idx].p_vaddr); } +static unsigned long maximum_alignment(struct elf_phdr *cmds, int nr) +{ + unsigned long alignment = 0; + int i; + + for (i = 0; i < nr; i++) { + if (cmds[i].p_type == PT_LOAD) { + unsigned long p_align = cmds[i].p_align; + + /* skip non-power of two alignments as invalid */ + if (!is_power_of_2(p_align)) + continue; + alignment = max(alignment, p_align); + } + } + + /* ensure we align to at least one page */ + return ELF_PAGEALIGN(alignment); +} + /** * load_elf_phdrs() - load ELF program headers * @elf_ex: ELF header of the binary whose program headers should be loaded @@ -898,6 +919,7 @@ static int load_elf_binary(struct linux_binprm *bprm) int elf_prot = 0, elf_flags, elf_fixed = MAP_FIXED_NOREPLACE; unsigned long k, vaddr; unsigned long total_size = 0; + unsigned long alignment; if (elf_ppnt->p_type != PT_LOAD) continue; @@ -987,6 +1009,9 @@ static int load_elf_binary(struct linux_binprm *bprm) load_bias = ELF_ET_DYN_BASE; if (current->flags & PF_RANDOMIZE) load_bias += arch_mmap_rnd(); + alignment = maximum_alignment(elf_phdata, loc->elf_ex.e_phnum); + if (alignment) + load_bias &= ~(alignment - 1); elf_flags |= elf_fixed; } else load_bias = 0;