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Subject[PATCH] binfmt_elf_fdpic: Fix clear_user() error handling
Date
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>

clear_user() returns the number of bytes that could not be copied rather than
an error code. So we should return -EFAULT rather than directly returning the
results.

Without this patch, positive values may be returned to elf_fdpic_map_file()
and the following error handlings do not function as expected.

1.
ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
if (ret < 0)
return ret;
2.
ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
if (ret < 0)
return ret;

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
CC: Paul Mundt <lethal@linux-sh.org>
---

fs/binfmt_elf_fdpic.c | 26 +++++++++++---------------
1 files changed, 11 insertions(+), 15 deletions(-)


diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 2c5f9a0..63039ed 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -990,10 +990,9 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(

/* clear any space allocated but not loaded */
if (phdr->p_filesz < phdr->p_memsz) {
- ret = clear_user((void *) (seg->addr + phdr->p_filesz),
- phdr->p_memsz - phdr->p_filesz);
- if (ret)
- return ret;
+ if (clear_user((void *) (seg->addr + phdr->p_filesz),
+ phdr->p_memsz - phdr->p_filesz))
+ return -EFAULT;
}

if (mm) {
@@ -1027,7 +1026,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
struct elf32_fdpic_loadseg *seg;
struct elf32_phdr *phdr;
unsigned long load_addr, delta_vaddr;
- int loop, dvset, ret;
+ int loop, dvset;

load_addr = params->load_addr;
delta_vaddr = 0;
@@ -1127,9 +1126,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
* PT_LOAD */
if (prot & PROT_WRITE && disp > 0) {
kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
- ret = clear_user((void __user *) maddr, disp);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr, disp))
+ return -EFAULT;
maddr += disp;
}

@@ -1164,19 +1162,17 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
if (prot & PROT_WRITE && excess1 > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess1);
- ret = clear_user((void __user *) maddr + phdr->p_filesz,
- excess1);
- if (ret)
- return ret;
+ if (clear_user((void __user *) maddr + phdr->p_filesz,
+ excess1))
+ return -EFAULT;
}

#else
if (excess > 0) {
kdebug("clear[%d] ad=%lx sz=%lx",
loop, maddr + phdr->p_filesz, excess);
- ret = clear_user((void *) maddr + phdr->p_filesz, excess);
- if (ret)
- return ret;
+ if (clear_user((void *) maddr + phdr->p_filesz, excess))
+ return -EFAULT;
}
#endif



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