Handle arbitrary memsz>filesz in interpreter ELF segments, instead of only supporting it in the last segment (which is expected to be the BSS). Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Christian Brauner <brauner@xxxxxxxxxx> Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Reported-by: Pedro Falcato <pedro.falcato@xxxxxxxxx> Closes: https://lore.kernel.org/lkml/20221106021657.1145519-1-pedro.falcato@xxxxxxxxx/ Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- fs/binfmt_elf.c | 46 +--------------------------------------------- 1 file changed, 1 insertion(+), 45 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index b939cfe3215c..74af5c8319a0 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -635,8 +635,6 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, struct elf_phdr *eppnt; unsigned long load_addr = 0; int load_addr_set = 0; - unsigned long last_bss = 0, elf_bss = 0; - int bss_prot = 0; unsigned long error = ~0UL; unsigned long total_size; int i; @@ -673,7 +671,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, else if (no_base && interp_elf_ex->e_type == ET_DYN) load_addr = -vaddr; - map_addr = elf_map(interpreter, load_addr + vaddr, + map_addr = elf_load(interpreter, load_addr + vaddr, eppnt, elf_prot, elf_type, total_size); total_size = 0; error = map_addr; @@ -699,51 +697,9 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, error = -ENOMEM; goto out; } - - /* - * Find the end of the file mapping for this phdr, and - * keep track of the largest address we see for this. - */ - k = load_addr + eppnt->p_vaddr + eppnt->p_filesz; - if (k > elf_bss) - elf_bss = k; - - /* - * Do the same thing for the memory mapping - between - * elf_bss and last_bss is the bss section. - */ - k = load_addr + eppnt->p_vaddr + eppnt->p_memsz; - if (k > last_bss) { - last_bss = k; - bss_prot = elf_prot; - } } } - /* - * Now fill out the bss section: first pad the last page from - * the file up to the page boundary, and zero it from elf_bss - * up to the end of the page. - */ - if (padzero(elf_bss, bss_prot)) { - error = -EFAULT; - goto out; - } - /* - * Next, align both the file and mem bss up to the page size, - * since this is where elf_bss was just zeroed up to, and where - * last_bss will end after the vm_brk_flags() below. - */ - elf_bss = ELF_PAGEALIGN(elf_bss); - last_bss = ELF_PAGEALIGN(last_bss); - /* Finally, if there is still more bss to allocate, do it. */ - if (last_bss > elf_bss) { - error = vm_brk_flags(elf_bss, last_bss - elf_bss, - bss_prot & PROT_EXEC ? VM_EXEC : 0); - if (error) - goto out; - } - error = load_addr; out: return error; -- 2.34.1
