1 files changed, 60 insertions, 92 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index b73b4de8fb36..b8f06273353e 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -292,101 +292,69 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
 		}
 	} else {
 		/*
-		 * Command line (1 string) occupies ARGV and maybe
-		 * extends into ENVP.
-		 */
-		if (len1 + len2 <= *pos)
-			goto skip_argv_envp;
-		if (len1 <= *pos)
-			goto skip_argv;
-
-		p = arg_start + *pos;
-		len = len1 - *pos;
-		while (count > 0 && len > 0) {
-			unsigned int _count, l;
-			int nr_read;
-			bool final;
-
-			_count = min3(count, len, PAGE_SIZE);
-			nr_read = access_remote_vm(mm, p, page, _count, 0);
-			if (nr_read < 0)
-				rv = nr_read;
-			if (nr_read <= 0)
-				goto out_free_page;
-
-			/*
-			 * Command line can be shorter than whole ARGV
-			 * even if last "marker" byte says it is not.
-			 */
-			final = false;
-			l = strnlen(page, nr_read);
-			if (l < nr_read) {
-				nr_read = l;
-				final = true;
-			}
-
-			if (copy_to_user(buf, page, nr_read)) {
-				rv = -EFAULT;
-				goto out_free_page;
-			}
-
-			p	+= nr_read;
-			len	-= nr_read;
-			buf	+= nr_read;
-			count	-= nr_read;
-			rv	+= nr_read;
-
-			if (final)
-				goto out_free_page;
-		}
-skip_argv:
-		/*
 		 * Command line (1 string) occupies ARGV and
 		 * extends into ENVP.
 		 */
-		if (len1 <= *pos) {
-			p = env_start + *pos - len1;
-			len = len1 + len2 - *pos;
-		} else {
-			p = env_start;
-			len = len2;
+		struct {
+			unsigned long p;
+			unsigned long len;
+		} cmdline[2] = {
+			{ .p = arg_start, .len = len1 },
+			{ .p = env_start, .len = len2 },
+		};
+		loff_t pos1 = *pos;
+		unsigned int i;
+
+		i = 0;
+		while (i < 2 && pos1 >= cmdline[i].len) {
+			pos1 -= cmdline[i].len;
+			i++;
 		}
-		while (count > 0 && len > 0) {
-			unsigned int _count, l;
-			int nr_read;
-			bool final;
-
-			_count = min3(count, len, PAGE_SIZE);
-			nr_read = access_remote_vm(mm, p, page, _count, 0);
-			if (nr_read < 0)
-				rv = nr_read;
-			if (nr_read <= 0)
-				goto out_free_page;
-
-			/* Find EOS. */
-			final = false;
-			l = strnlen(page, nr_read);
-			if (l < nr_read) {
-				nr_read = l;
-				final = true;
-			}
-
-			if (copy_to_user(buf, page, nr_read)) {
-				rv = -EFAULT;
-				goto out_free_page;
+		while (i < 2) {
+			p = cmdline[i].p + pos1;
+			len = cmdline[i].len - pos1;
+			while (count > 0 && len > 0) {
+				unsigned int _count, l;
+				int nr_read;
+				bool final;
+
+				_count = min3(count, len, PAGE_SIZE);
+				nr_read = access_remote_vm(mm, p, page, _count, 0);
+				if (nr_read < 0)
+					rv = nr_read;
+				if (nr_read <= 0)
+					goto out_free_page;
+
+				/*
+				 * Command line can be shorter than whole ARGV
+				 * even if last "marker" byte says it is not.
+				 */
+				final = false;
+				l = strnlen(page, nr_read);
+				if (l < nr_read) {
+					nr_read = l;
+					final = true;
+				}
+
+				if (copy_to_user(buf, page, nr_read)) {
+					rv = -EFAULT;
+					goto out_free_page;
+				}
+
+				p	+= nr_read;
+				len	-= nr_read;
+				buf	+= nr_read;
+				count	-= nr_read;
+				rv	+= nr_read;
+
+				if (final)
+					goto out_free_page;
 			}
 
-			p	+= nr_read;
-			len	-= nr_read;
-			buf	+= nr_read;
-			count	-= nr_read;
-			rv	+= nr_read;
-
-			if (final)
-				goto out_free_page;
+			/* Only first chunk can be read partially. */
+			pos1 = 0;
+			i++;
 		}
-skip_argv_envp:
-		;
 	}
 
 out_free_page:
@@ -729,11 +697,11 @@ static int proc_pid_permission(struct inode *inode, int mask)
 	task = get_proc_task(inode);
 	if (!task)
 		return -ESRCH;
-	has_perms = has_pid_permissions(pid, task, 1);
+	has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);
 	put_task_struct(task);
 
 	if (!has_perms) {
-		if (pid->hide_pid == 2) {
+		if (pid->hide_pid == HIDEPID_INVISIBLE) {
 			/*
 			 * Let's make getdents(), stat(), and open()
 			 * consistent with each other.  If a process
@@ -1769,7 +1737,7 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 	stat->gid = GLOBAL_ROOT_GID;
 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
 	if (task) {
-		if (!has_pid_permissions(pid, task, 2)) {
+		if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {
 			rcu_read_unlock();
 			/*
 			 * This doesn't prevent learning whether PID exists,
@@ -3200,7 +3168,7 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx)
 		int len;
 
 		cond_resched();
-		if (!has_pid_permissions(ns, iter.task, 2))
+		if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
 			continue;
 
 		len = snprintf(name, sizeof(name), "%d", iter.tgid);