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-rw-r--r--fs/compat.c128
1 files changed, 53 insertions, 75 deletions
diff --git a/fs/compat.c b/fs/compat.c
index 4db6216e5266..15078ce4c04a 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1257,6 +1257,7 @@ static int compat_copy_strings(int argc, compat_uptr_t __user *argv,
{
struct page *kmapped_page = NULL;
char *kaddr = NULL;
+ unsigned long kpos = 0;
int ret;
while (argc-- > 0) {
@@ -1265,92 +1266,84 @@ static int compat_copy_strings(int argc, compat_uptr_t __user *argv,
unsigned long pos;
if (get_user(str, argv+argc) ||
- !(len = strnlen_user(compat_ptr(str), bprm->p))) {
+ !(len = strnlen_user(compat_ptr(str), MAX_ARG_STRLEN))) {
ret = -EFAULT;
goto out;
}
- if (bprm->p < len) {
+ if (len > MAX_ARG_STRLEN) {
ret = -E2BIG;
goto out;
}
- bprm->p -= len;
- /* XXX: add architecture specific overflow check here. */
+ /* We're going to work our way backwords. */
pos = bprm->p;
+ str += len;
+ bprm->p -= len;
while (len > 0) {
- int i, new, err;
int offset, bytes_to_copy;
- struct page *page;
offset = pos % PAGE_SIZE;
- i = pos/PAGE_SIZE;
- page = bprm->page[i];
- new = 0;
- if (!page) {
- page = alloc_page(GFP_HIGHUSER);
- bprm->page[i] = page;
- if (!page) {
- ret = -ENOMEM;
+ 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;
+
+#ifdef CONFIG_STACK_GROWSUP
+ ret = expand_stack_downwards(bprm->vma, pos);
+ if (ret < 0) {
+ /* We've exceed the stack rlimit. */
+ ret = -E2BIG;
+ goto out;
+ }
+#endif
+ ret = get_user_pages(current, bprm->mm, pos,
+ 1, 1, 1, &page, NULL);
+ if (ret <= 0) {
+ /* We've exceed the stack rlimit. */
+ ret = -E2BIG;
goto out;
}
- new = 1;
- }
- if (page != kmapped_page) {
- if (kmapped_page)
+ 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 (new && offset)
- memset(kaddr, 0, offset);
- bytes_to_copy = PAGE_SIZE - offset;
- if (bytes_to_copy > len) {
- bytes_to_copy = len;
- if (new)
- memset(kaddr+offset+len, 0,
- PAGE_SIZE-offset-len);
- }
- err = copy_from_user(kaddr+offset, compat_ptr(str),
- bytes_to_copy);
- if (err) {
+ if (copy_from_user(kaddr+offset, compat_ptr(str),
+ bytes_to_copy)) {
ret = -EFAULT;
goto out;
}
-
- pos += bytes_to_copy;
- str += bytes_to_copy;
- len -= bytes_to_copy;
}
}
ret = 0;
out:
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
- return ret;
-}
-
-#ifdef CONFIG_MMU
-
-#define free_arg_pages(bprm) do { } while (0)
-
-#else
-
-static inline void free_arg_pages(struct linux_binprm *bprm)
-{
- int i;
-
- for (i = 0; i < MAX_ARG_PAGES; i++) {
- if (bprm->page[i])
- __free_page(bprm->page[i]);
- bprm->page[i] = NULL;
+ put_page(kmapped_page);
}
+ return ret;
}
-#endif /* CONFIG_MMU */
-
/*
* compat_do_execve() is mostly a copy of do_execve(), with the exception
* that it processes 32 bit argv and envp pointers.
@@ -1363,7 +1356,6 @@ int compat_do_execve(char * filename,
struct linux_binprm *bprm;
struct file *file;
int retval;
- int i;
retval = -ENOMEM;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
@@ -1377,24 +1369,19 @@ int compat_do_execve(char * filename,
sched_exec();
- bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
bprm->file = file;
bprm->filename = filename;
bprm->interp = filename;
- bprm->mm = mm_alloc();
- retval = -ENOMEM;
- if (!bprm->mm)
- goto out_file;
- retval = init_new_context(current, bprm->mm);
- if (retval < 0)
- goto out_mm;
+ retval = bprm_mm_init(bprm);
+ if (retval)
+ goto out_file;
- bprm->argc = compat_count(argv, bprm->p / sizeof(compat_uptr_t));
+ bprm->argc = compat_count(argv, MAX_ARG_STRINGS);
if ((retval = bprm->argc) < 0)
goto out_mm;
- bprm->envc = compat_count(envp, bprm->p / sizeof(compat_uptr_t));
+ bprm->envc = compat_count(envp, MAX_ARG_STRINGS);
if ((retval = bprm->envc) < 0)
goto out_mm;
@@ -1421,8 +1408,6 @@ int compat_do_execve(char * filename,
retval = search_binary_handler(bprm, regs);
if (retval >= 0) {
- free_arg_pages(bprm);
-
/* execve success */
security_bprm_free(bprm);
acct_update_integrals(current);
@@ -1431,19 +1416,12 @@ int compat_do_execve(char * filename,
}
out:
- /* Something went wrong, return the inode and free the argument pages*/
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page * page = bprm->page[i];
- if (page)
- __free_page(page);
- }
-
if (bprm->security)
security_bprm_free(bprm);
out_mm:
if (bprm->mm)
- mmdrop(bprm->mm);
+ mmput(bprm->mm);
out_file:
if (bprm->file) {