Re: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC
From: Kees Cook <hidden>
Date: 2020-05-14 03:05:18
Also in:
linux-api, linux-fsdevel, linux-security-module, lkml
On Wed, May 13, 2020 at 04:27:39PM -0700, Kees Cook wrote:
quoted hunk ↗ jump to hunk
Like, couldn't just the entire thing just be:diff --git a/fs/namei.c b/fs/namei.c index a320371899cf..0ab18e19f5da 100644 --- a/fs/namei.c +++ b/fs/namei.c@@ -2849,6 +2849,13 @@ static int may_open(const struct path *path, int acc_mode, int flag) break; } + if (unlikely(mask & MAY_OPENEXEC)) { + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_MOUNT && + path_noexec(path)) + return -EACCES; + if (sysctl_omayexec_enforce & OMAYEXEC_ENFORCE_FILE) + acc_mode |= MAY_EXEC; + } error = inode_permission(inode, MAY_OPEN | acc_mode); if (error) return error;
FYI, I've confirmed this now. Effectively with patch 2 dropped, patch 3 reduced to this plus the Kconfig and sysctl changes, the self tests pass. I think this makes things much cleaner and correct. -- Kees Cook