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author | Oleg Nesterov <oleg@redhat.com> | 2011-03-06 18:02:37 +0100 |
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committer | Oleg Nesterov <oleg@redhat.com> | 2011-04-09 15:53:53 +0200 |
commit | ba2d01629d0d167598cfea85adc7926822bbfc45 (patch) | |
tree | 703a3f297df7cb4c0317504a58121f9958c0d708 /fs | |
parent | exec: introduce get_user_arg_ptr() helper (diff) | |
download | linux-ba2d01629d0d167598cfea85adc7926822bbfc45.tar.xz linux-ba2d01629d0d167598cfea85adc7926822bbfc45.zip |
exec: introduce struct user_arg_ptr
No functional changes, preparation.
Introduce struct user_arg_ptr, change do_execve() paths to use it
instead of "char __user * const __user *argv".
This makes the argv/envp arguments opaque, we are ready to handle the
compat case which needs argv pointing to compat_uptr_t.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/exec.c | 42 |
1 files changed, 30 insertions, 12 deletions
diff --git a/fs/exec.c b/fs/exec.c index b12e24fe1c5e..526a0399d963 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -398,12 +398,15 @@ err: return err; } -static const char __user * -get_user_arg_ptr(const char __user * const __user *argv, int nr) +struct user_arg_ptr { + const char __user *const __user *native; +}; + +static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) { const char __user *ptr; - if (get_user(ptr, argv + nr)) + if (get_user(ptr, argv.native + nr)) return ERR_PTR(-EFAULT); return ptr; @@ -412,11 +415,11 @@ get_user_arg_ptr(const char __user * const __user *argv, int nr) /* * 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.native != NULL) { for (;;) { const char __user *p = get_user_arg_ptr(argv, i); @@ -442,7 +445,7 @@ 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; @@ -533,14 +536,19 @@ 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 = { + .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); @@ -1393,10 +1401,10 @@ 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; @@ -1503,6 +1511,16 @@ 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 = { .native = __argv }; + struct user_arg_ptr envp = { .native = __envp }; + return do_execve_common(filename, argv, envp, regs); +} + void set_binfmt(struct linux_binfmt *new) { struct mm_struct *mm = current->mm; |