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-rw-r--r--fs/proc/base.c71
1 files changed, 8 insertions, 63 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 255f6754c70d..8040f9d1cf07 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -212,7 +212,7 @@ static int proc_root_link(struct dentry *dentry, struct path *path)
static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
size_t count, loff_t *ppos)
{
- unsigned long arg_start, arg_end, env_start, env_end;
+ unsigned long arg_start, arg_end;
unsigned long pos, len;
char *page;
@@ -223,36 +223,18 @@ static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
spin_lock(&mm->arg_lock);
arg_start = mm->arg_start;
arg_end = mm->arg_end;
- env_start = mm->env_start;
- env_end = mm->env_end;
spin_unlock(&mm->arg_lock);
if (arg_start >= arg_end)
return 0;
- /*
- * We have traditionally allowed the user to re-write
- * the argument strings and overflow the end result
- * into the environment section. But only do that if
- * the environment area is contiguous to the arguments.
- */
- if (env_start != arg_end || env_start >= env_end)
- env_start = env_end = arg_end;
-
- /* .. and limit it to a maximum of one page of slop */
- if (env_end >= arg_end + PAGE_SIZE)
- env_end = arg_end + PAGE_SIZE - 1;
-
/* We're not going to care if "*ppos" has high bits set */
- pos = arg_start + *ppos;
-
/* .. but we do check the result is in the proper range */
- if (pos < arg_start || pos >= env_end)
+ pos = arg_start + *ppos;
+ if (pos < arg_start || pos >= arg_end)
return 0;
-
- /* .. and we never go past env_end */
- if (env_end - pos < count)
- count = env_end - pos;
+ if (count > arg_end - pos)
+ count = arg_end - pos;
page = (char *)__get_free_page(GFP_KERNEL);
if (!page)
@@ -262,48 +244,11 @@ static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
while (count) {
int got;
size_t size = min_t(size_t, PAGE_SIZE, count);
- long offset;
- /*
- * Are we already starting past the official end?
- * We always include the last byte that is *supposed*
- * to be NUL
- */
- offset = (pos >= arg_end) ? pos - arg_end + 1 : 0;
-
- got = access_remote_vm(mm, pos - offset, page, size + offset, FOLL_ANON);
- if (got <= offset)
+ got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
+ if (got <= 0)
break;
- got -= offset;
-
- /* Don't walk past a NUL character once you hit arg_end */
- if (pos + got >= arg_end) {
- int n = 0;
-
- /*
- * If we started before 'arg_end' but ended up
- * at or after it, we start the NUL character
- * check at arg_end-1 (where we expect the normal
- * EOF to be).
- *
- * NOTE! This is smaller than 'got', because
- * pos + got >= arg_end
- */
- if (pos < arg_end)
- n = arg_end - pos - 1;
-
- /* Cut off at first NUL after 'n' */
- got = n + strnlen(page+n, offset+got-n);
- if (got < offset)
- break;
- got -= offset;
-
- /* Include the NUL if it existed */
- if (got < size)
- got++;
- }
-
- got -= copy_to_user(buf, page+offset, got);
+ got -= copy_to_user(buf, page, got);
if (unlikely(!got)) {
if (!len)
len = -EFAULT;