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Subject[PATCH 4/9] binfmt_flat: don't use __put_user()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

... and check the return value

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/binfmt_flat.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 831a2b25ba79..7b663ed5247b 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -138,35 +138,40 @@ static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start
current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
sp = (unsigned long __user *)current->mm->start_stack;

- __put_user(bprm->argc, sp++);
+ if (put_user(bprm->argc, sp++))
+ return -EFAULT;
if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
unsigned long argv, envp;
argv = (unsigned long)(sp + 2);
envp = (unsigned long)(sp + 2 + bprm->argc + 1);
- __put_user(argv, sp++);
- __put_user(envp, sp++);
+ if (put_user(argv, sp++) || put_user(envp, sp++))
+ return -EFAULT;
}

current->mm->arg_start = (unsigned long)p;
for (i = bprm->argc; i > 0; i--) {
- __put_user((unsigned long)p, sp++);
+ if (put_user((unsigned long)p, sp++))
+ return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
- __put_user(0, sp++);
+ if (put_user(0, sp++))
+ return -EFAULT;
current->mm->arg_end = (unsigned long)p;

current->mm->env_start = (unsigned long) p;
for (i = bprm->envc; i > 0; i--) {
- __put_user((unsigned long)p, sp++);
+ if (put_user((unsigned long)p, sp++))
+ return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
- __put_user(0, sp++);
+ if (put_user(0, sp++))
+ return -EFAULT;
current->mm->env_end = (unsigned long)p;

return 0;
@@ -998,7 +1003,8 @@ static int load_flat_binary(struct linux_binprm *bprm)
unsigned long __user *sp;
current->mm->start_stack -= sizeof(unsigned long);
sp = (unsigned long __user *)current->mm->start_stack;
- __put_user(start_addr, sp);
+ if (put_user(start_addr, sp))
+ return -EFAULT;
start_addr = libinfo.lib_list[i].entry;
}
}
--
2.11.0
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