From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: fs/binfmt_elf.c: allocate less for static executable PT_INTERP ELF header can be spared if executable is static. Link: http://lkml.kernel.org/r/20200219185012.GB4871@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/binfmt_elf.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/fs/binfmt_elf.c~elf-allocate-less-for-static-executable +++ a/fs/binfmt_elf.c @@ -699,17 +699,11 @@ static int load_elf_binary(struct linux_ unsigned long reloc_func_desc __maybe_unused = 0; int executable_stack = EXSTACK_DEFAULT; struct elfhdr *elf_ex = (struct elfhdr *)bprm->buf; - struct elfhdr *interp_elf_ex; + struct elfhdr *interp_elf_ex = NULL; struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE; struct mm_struct *mm; struct pt_regs *regs; - interp_elf_ex = kmalloc(sizeof(*interp_elf_ex), GFP_KERNEL); - if (!interp_elf_ex) { - retval = -ENOMEM; - goto out_ret; - } - retval = -ENOEXEC; /* First of all, some simple consistency checks */ if (memcmp(elf_ex->e_ident, ELFMAG, SELFMAG) != 0) @@ -769,6 +763,12 @@ static int load_elf_binary(struct linux_ */ would_dump(bprm, interpreter); + interp_elf_ex = kmalloc(sizeof(*interp_elf_ex), GFP_KERNEL); + if (!interp_elf_ex) { + retval = -ENOMEM; + goto out_free_ph; + } + /* Get the exec headers */ retval = elf_read(interpreter, interp_elf_ex, sizeof(*interp_elf_ex), 0); @@ -1074,6 +1074,8 @@ out_free_interp: allow_write_access(interpreter); fput(interpreter); + + kfree(interp_elf_ex); } else { elf_entry = e_entry; if (BAD_ADDR(elf_entry)) { @@ -1152,12 +1154,11 @@ out_free_interp: start_thread(regs, elf_entry, bprm->p); retval = 0; out: - kfree(interp_elf_ex); -out_ret: return retval; /* error cleanup */ out_free_dentry: + kfree(interp_elf_ex); kfree(interp_elf_phdata); allow_write_access(interpreter); if (interpreter) _
