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[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 <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -288,11 +288,17 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
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struct elf_phdr *eppnt, int prot, int type)
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{
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unsigned long map_addr;
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unsigned long pageoffset = ELF_PAGEOFFSET(eppnt->p_vaddr);
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down_write(¤t->mm->mmap_sem);
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map_addr = do_mmap(filep, ELF_PAGESTART(addr),
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eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr), prot, type,
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eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr));
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/* mmap() will return -EINVAL if given a zero size, but a
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* segment with zero filesize is perfectly valid */
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if (eppnt->p_filesz + pageoffset)
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map_addr = do_mmap(filep, ELF_PAGESTART(addr),
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eppnt->p_filesz + pageoffset, prot, type,
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eppnt->p_offset - pageoffset);
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else
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map_addr = ELF_PAGESTART(addr);
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up_write(¤t->mm->mmap_sem);
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return(map_addr);
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}
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