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authorDavid Gibson <david@gibson.dropbear.id.au>2006-01-08 01:03:35 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:58 -0800
commitdda6ebde96044e9b5f1b14588659b39b4e6c08e7 (patch)
treec06bba58d2623784c88acc321137c34b7be16335
parentcc398c2eae35b13d77b77337136325edc6ca94ca (diff)
[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>
-rw-r--r--fs/binfmt_elf.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f36f2210204..288386b1def 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(&current->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(&current->mm->mmap_sem);
return(map_addr);
}