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Merge branch 'exec_rm_compat' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc

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* 'exec_rm_compat' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc:
  exec: document acct_arg_size()
  exec: unify do_execve/compat_do_execve code
  exec: introduce struct user_arg_ptr
  exec: introduce get_user_arg_ptr() helper
This commit is contained in:
Linus Torvalds
2011-05-23 08:28:34 -07:00
parent 34b064569e ae6b585eeb
commit 4d9dec4db2
3 changed files with 100 additions and 264 deletions
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125
fs/exec.c
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@@ -55,6 +55,7 @@
#include <linux/fs_struct.h>
#include <linux/pipe_fs_i.h>
#include <linux/oom.h>
#include <linux/compat.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
@@ -166,8 +167,13 @@ out:
}
#ifdef CONFIG_MMU
void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
/*
* The nascent bprm->mm is not visible until exec_mmap() but it can
* use a lot of memory, account these pages in current->mm temporary
* for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
* change the counter back via acct_arg_size(0).
*/
static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
{
struct mm_struct *mm = current->mm;
long diff = (long)(pages - bprm->vma_pages);
@@ -186,7 +192,7 @@ void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
#endif
}
struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
int write)
{
struct page *page;
@@ -305,11 +311,11 @@ static bool valid_arg_len(struct linux_binprm *bprm, long len)
#else
void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
{
}
struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
int write)
{
struct page *page;
@@ -398,22 +404,56 @@ err:
return err;
}
struct user_arg_ptr {
#ifdef CONFIG_COMPAT
bool is_compat;
#endif
union {
const char __user *const __user *native;
#ifdef CONFIG_COMPAT
compat_uptr_t __user *compat;
#endif
} ptr;
};
static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
{
const char __user *native;
#ifdef CONFIG_COMPAT
if (unlikely(argv.is_compat)) {
compat_uptr_t compat;
if (get_user(compat, argv.ptr.compat + nr))
return ERR_PTR(-EFAULT);
return compat_ptr(compat);
}
#endif
if (get_user(native, argv.ptr.native + nr))
return ERR_PTR(-EFAULT);
return native;
}
/*
* count() counts the number of strings in array ARGV.
*/
static int count(const char __user * const __user * argv, int max)
static int count(struct user_arg_ptr argv, int max)
{
int i = 0;
if (argv != NULL) {
if (argv.ptr.native != NULL) {
for (;;) {
const char __user * p;
const char __user *p = get_user_arg_ptr(argv, i);
if (get_user(p, argv))
return -EFAULT;
if (!p)
break;
argv++;
if (IS_ERR(p))
return -EFAULT;
if (i++ >= max)
return -E2BIG;
@@ -430,7 +470,7 @@ static int count(const char __user * const __user * argv, int max)
* processes's memory to the new process's stack. The call to get_user_pages()
* ensures the destination page is created and not swapped out.
*/
static int copy_strings(int argc, const char __user *const __user *argv,
static int copy_strings(int argc, struct user_arg_ptr argv,
struct linux_binprm *bprm)
{
struct page *kmapped_page = NULL;
@@ -443,16 +483,18 @@ static int copy_strings(int argc, const char __user *const __user *argv,
int len;
unsigned long pos;
if (get_user(str, argv+argc) ||
!(len = strnlen_user(str, MAX_ARG_STRLEN))) {
ret = -EFAULT;
ret = -EFAULT;
str = get_user_arg_ptr(argv, argc);
if (IS_ERR(str))
goto out;
}
if (!valid_arg_len(bprm, len)) {
ret = -E2BIG;
len = strnlen_user(str, MAX_ARG_STRLEN);
if (!len)
goto out;
ret = -E2BIG;
if (!valid_arg_len(bprm, len))
goto out;
}
/* We're going to work our way backwords. */
pos = bprm->p;
@@ -519,14 +561,19 @@ out:
/*
* Like copy_strings, but get argv and its values from kernel memory.
*/
int copy_strings_kernel(int argc, const char *const *argv,
int copy_strings_kernel(int argc, const char *const *__argv,
struct linux_binprm *bprm)
{
int r;
mm_segment_t oldfs = get_fs();
struct user_arg_ptr argv = {
.ptr.native = (const char __user *const __user *)__argv,
};
set_fs(KERNEL_DS);
r = copy_strings(argc, (const char __user *const __user *)argv, bprm);
r = copy_strings(argc, argv, bprm);
set_fs(oldfs);
return r;
}
EXPORT_SYMBOL(copy_strings_kernel);
@@ -1379,10 +1426,10 @@ EXPORT_SYMBOL(search_binary_handler);
/*
* sys_execve() executes a new program.
*/
int do_execve(const char * filename,
const char __user *const __user *argv,
const char __user *const __user *envp,
struct pt_regs * regs)
static int do_execve_common(const char *filename,
struct user_arg_ptr argv,
struct user_arg_ptr envp,
struct pt_regs *regs)
{
struct linux_binprm *bprm;
struct file *file;
@@ -1489,6 +1536,34 @@ out_ret:
return retval;
}
int do_execve(const char *filename,
const char __user *const __user *__argv,
const char __user *const __user *__envp,
struct pt_regs *regs)
{
struct user_arg_ptr argv = { .ptr.native = __argv };
struct user_arg_ptr envp = { .ptr.native = __envp };
return do_execve_common(filename, argv, envp, regs);
}
#ifdef CONFIG_COMPAT
int compat_do_execve(char *filename,
compat_uptr_t __user *__argv,
compat_uptr_t __user *__envp,
struct pt_regs *regs)
{
struct user_arg_ptr argv = {
.is_compat = true,
.ptr.compat = __argv,
};
struct user_arg_ptr envp = {
.is_compat = true,
.ptr.compat = __envp,
};
return do_execve_common(filename, argv, envp, regs);
}
#endif
void set_binfmt(struct linux_binfmt *new)
{
struct mm_struct *mm = current->mm;