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authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-23 08:28:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-23 08:28:34 -0700
commit4d9dec4db2efbd7edb549bd02373995b67496983 (patch)
treea0ddbecea4823a7f3e20ab6eacb37a086a72dc36 /fs/exec.c
parent34b064569eba3bec65bf98efe057b0578fe13297 (diff)
parentae6b585eeb74670a2dec1fe4394bdfbdb9395cc2 (diff)
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Merge branch 'exec_rm_compat' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc
* '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
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c125
1 files changed, 100 insertions, 25 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 8328beb9016..c016896dcbb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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;