There is a false positive WARNON happening in execve(2)/uselib(2)
syscalls with concurrent noexec-remount.
execveat remount
do_open_execat(path/bin)
do_filp_open
path_openat
do_open
may_open
path_noexec() // PASS
remount(path->mnt, MS_NOEXEC)
WARNON(path_noexec(&file->f_path)) // path_noexec() checks fail
Since may_open() has already checked the same conditions, fix it by
removing 'S_ISREG' and 'path_noexec' check in do_open_execat()/uselib(2).
Fixes: 0fd338b2d2cdf8 ("exec: move path_noexec() check earlier")
Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
---
fs/exec.c | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index e3e55d5e0be1..0f8ea7e9e03c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -141,16 +141,6 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
if (IS_ERR(file))
goto out;
- /*
- * may_open() has already checked for this, so it should be
- * impossible to trip now. But we need to be extra cautious
- * and check again at the very end too.
- */
- error = -EACCES;
- if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
- path_noexec(&file->f_path)))
- goto exit;
-
fsnotify_open(file);
error = -ENOEXEC;
@@ -169,7 +159,7 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
break;
}
read_unlock(&binfmt_lock);
-exit:
+
fput(file);
out:
return error;
@@ -919,16 +909,6 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
if (IS_ERR(file))
goto out;
- /*
- * may_open() has already checked for this, so it should be
- * impossible to trip now. But we need to be extra cautious
- * and check again at the very end too.
- */
- err = -EACCES;
- if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
- path_noexec(&file->f_path)))
- goto exit;
-
err = deny_write_access(file);
if (err)
goto exit;
--
2.31.1
