From: David Gibson Date: Sun, 8 Jan 2006 09:03:35 +0000 (-0800) Subject: [PATCH] Fix handling of ELF segments with zero filesize X-Git-Tag: v2.6.16-rc1~748 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dda6ebde96044e9b5f1b14588659b39b4e6c08e7;p=linux-2.6 [PATCH] Fix handling of ELF segments with zero filesize mmap() returns -EINVAL if given a zero length, and thus elf_map() in binfmt_elf.c does likewise if it attempts to map a (page-aligned) ELF segment with zero filesize. Such a situation never arises with the default linker scripts, but there's nothing inherently wrong with zero-filesize (but non-zero memsize) ELF segments. Custom linker scripts can generate them, and the kernel should be able to map them; this patch makes it so. Signed-off-by: David Gibson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f36f221020..288386b1de 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -288,11 +288,17 @@ static unsigned long elf_map(struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type) { unsigned long map_addr; + unsigned long pageoffset = ELF_PAGEOFFSET(eppnt->p_vaddr); down_write(¤t->mm->mmap_sem); - map_addr = do_mmap(filep, ELF_PAGESTART(addr), - eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr), prot, type, - eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr)); + /* mmap() will return -EINVAL if given a zero size, but a + * segment with zero filesize is perfectly valid */ + if (eppnt->p_filesz + pageoffset) + map_addr = do_mmap(filep, ELF_PAGESTART(addr), + eppnt->p_filesz + pageoffset, prot, type, + eppnt->p_offset - pageoffset); + else + map_addr = ELF_PAGESTART(addr); up_write(¤t->mm->mmap_sem); return(map_addr); }