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authorOleg Nesterov <oleg@redhat.com>2011-03-06 18:02:54 +0100
committerOleg Nesterov <oleg@redhat.com>2011-04-09 15:53:56 +0200
commit0e028465d18b7c6797fcbdea632299d16097c5cd (patch)
treed03a1f0f688e9c4a780b2a1a3ef8354378b0ad42 /fs/compat.c
parentba2d01629d0d167598cfea85adc7926822bbfc45 (diff)
downloadlinux-0e028465d18b7c6797fcbdea632299d16097c5cd.tar.gz
exec: unify do_execve/compat_do_execve code
Add the appropriate members into struct user_arg_ptr and teach get_user_arg_ptr() to handle is_compat = T case correctly. This allows us to remove the compat_do_execve() code from fs/compat.c and reimplement compat_do_execve() as the trivial wrapper on top of do_execve_common(is_compat => true). In fact, this fixes another (minor) bug. "compat_uptr_t str" can overflow after "str += len" in compat_copy_strings() if a 64bit application execs via sys32_execve(). Unexport acct_arg_size() and get_arg_page(), fs/compat.c doesn't need them any longer. 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/compat.c')
-rw-r--r--fs/compat.c235
1 files changed, 0 insertions, 235 deletions
diff --git a/fs/compat.c b/fs/compat.c
index 72fe6cda910..0ea00832de2 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1306,241 +1306,6 @@ compat_sys_openat(unsigned int dfd, const char __user *filename, int flags, int
return do_sys_open(dfd, filename, flags, mode);
}
-/*
- * compat_count() counts the number of arguments/envelopes. It is basically
- * a copy of count() from fs/exec.c, except that it works with 32 bit argv
- * and envp pointers.
- */
-static int compat_count(compat_uptr_t __user *argv, int max)
-{
- int i = 0;
-
- if (argv != NULL) {
- for (;;) {
- compat_uptr_t p;
-
- if (get_user(p, argv))
- return -EFAULT;
- if (!p)
- break;
- argv++;
- if (i++ >= max)
- return -E2BIG;
-
- if (fatal_signal_pending(current))
- return -ERESTARTNOHAND;
- cond_resched();
- }
- }
- return i;
-}
-
-/*
- * compat_copy_strings() is basically a copy of copy_strings() from fs/exec.c
- * except that it works with 32 bit argv and envp pointers.
- */
-static int compat_copy_strings(int argc, compat_uptr_t __user *argv,
- struct linux_binprm *bprm)
-{
- struct page *kmapped_page = NULL;
- char *kaddr = NULL;
- unsigned long kpos = 0;
- int ret;
-
- while (argc-- > 0) {
- compat_uptr_t str;
- int len;
- unsigned long pos;
-
- if (get_user(str, argv+argc) ||
- !(len = strnlen_user(compat_ptr(str), MAX_ARG_STRLEN))) {
- ret = -EFAULT;
- goto out;
- }
-
- if (len > MAX_ARG_STRLEN) {
- ret = -E2BIG;
- goto out;
- }
-
- /* We're going to work our way backwords. */
- pos = bprm->p;
- str += len;
- bprm->p -= len;
-
- while (len > 0) {
- int offset, bytes_to_copy;
-
- if (fatal_signal_pending(current)) {
- ret = -ERESTARTNOHAND;
- goto out;
- }
- cond_resched();
-
- offset = pos % PAGE_SIZE;
- if (offset == 0)
- offset = PAGE_SIZE;
-
- bytes_to_copy = offset;
- if (bytes_to_copy > len)
- bytes_to_copy = len;
-
- offset -= bytes_to_copy;
- pos -= bytes_to_copy;
- str -= bytes_to_copy;
- len -= bytes_to_copy;
-
- if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
- struct page *page;
-
- page = get_arg_page(bprm, pos, 1);
- if (!page) {
- ret = -E2BIG;
- goto out;
- }
-
- if (kmapped_page) {
- flush_kernel_dcache_page(kmapped_page);
- kunmap(kmapped_page);
- put_page(kmapped_page);
- }
- kmapped_page = page;
- kaddr = kmap(kmapped_page);
- kpos = pos & PAGE_MASK;
- flush_cache_page(bprm->vma, kpos,
- page_to_pfn(kmapped_page));
- }
- if (copy_from_user(kaddr+offset, compat_ptr(str),
- bytes_to_copy)) {
- ret = -EFAULT;
- goto out;
- }
- }
- }
- ret = 0;
-out:
- if (kmapped_page) {
- flush_kernel_dcache_page(kmapped_page);
- kunmap(kmapped_page);
- put_page(kmapped_page);
- }
- return ret;
-}
-
-/*
- * compat_do_execve() is mostly a copy of do_execve(), with the exception
- * that it processes 32 bit argv and envp pointers.
- */
-int compat_do_execve(char * filename,
- compat_uptr_t __user *argv,
- compat_uptr_t __user *envp,
- struct pt_regs * regs)
-{
- struct linux_binprm *bprm;
- struct file *file;
- struct files_struct *displaced;
- bool clear_in_exec;
- int retval;
-
- retval = unshare_files(&displaced);
- if (retval)
- goto out_ret;
-
- retval = -ENOMEM;
- bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
- if (!bprm)
- goto out_files;
-
- retval = prepare_bprm_creds(bprm);
- if (retval)
- goto out_free;
-
- retval = check_unsafe_exec(bprm);
- if (retval < 0)
- goto out_free;
- clear_in_exec = retval;
- current->in_execve = 1;
-
- file = open_exec(filename);
- retval = PTR_ERR(file);
- if (IS_ERR(file))
- goto out_unmark;
-
- sched_exec();
-
- bprm->file = file;
- bprm->filename = filename;
- bprm->interp = filename;
-
- retval = bprm_mm_init(bprm);
- if (retval)
- goto out_file;
-
- bprm->argc = compat_count(argv, MAX_ARG_STRINGS);
- if ((retval = bprm->argc) < 0)
- goto out;
-
- bprm->envc = compat_count(envp, MAX_ARG_STRINGS);
- if ((retval = bprm->envc) < 0)
- goto out;
-
- retval = prepare_binprm(bprm);
- if (retval < 0)
- goto out;
-
- retval = copy_strings_kernel(1, &bprm->filename, bprm);
- if (retval < 0)
- goto out;
-
- bprm->exec = bprm->p;
- retval = compat_copy_strings(bprm->envc, envp, bprm);
- if (retval < 0)
- goto out;
-
- retval = compat_copy_strings(bprm->argc, argv, bprm);
- if (retval < 0)
- goto out;
-
- retval = search_binary_handler(bprm, regs);
- if (retval < 0)
- goto out;
-
- /* execve succeeded */
- current->fs->in_exec = 0;
- current->in_execve = 0;
- acct_update_integrals(current);
- free_bprm(bprm);
- if (displaced)
- put_files_struct(displaced);
- return retval;
-
-out:
- if (bprm->mm) {
- acct_arg_size(bprm, 0);
- mmput(bprm->mm);
- }
-
-out_file:
- if (bprm->file) {
- allow_write_access(bprm->file);
- fput(bprm->file);
- }
-
-out_unmark:
- if (clear_in_exec)
- current->fs->in_exec = 0;
- current->in_execve = 0;
-
-out_free:
- free_bprm(bprm);
-
-out_files:
- if (displaced)
- reset_files_struct(displaced);
-out_ret:
- return retval;
-}
-
#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,