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| author | David Gibson <david@gibson.dropbear.id.au> | 2006-01-08 01:03:35 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-08 20:13:58 -0800 |
| commit | dda6ebde96044e9b5f1b14588659b39b4e6c08e7 (patch) | |
| tree | c06bba58d2623784c88acc321137c34b7be16335 /fs/binfmt_elf.c | |
| parent | cc398c2eae35b13d77b77337136325edc6ca94ca (diff) | |
| download | lwn-dda6ebde96044e9b5f1b14588659b39b4e6c08e7.tar.gz lwn-dda6ebde96044e9b5f1b14588659b39b4e6c08e7.zip | |
[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>
Diffstat (limited to 'fs/binfmt_elf.c')
| -rw-r--r-- | fs/binfmt_elf.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f36f2210204f..288386b1deff 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); } |