Commit db19c91c authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds

exec: change uselib(2) IS_SREG() failure to EACCES

Patch series "Relocate execve() sanity checks", v2.

While looking at the code paths for the proposed O_MAYEXEC flag, I saw
some things that looked like they should be fixed up.

  exec: Change uselib(2) IS_SREG() failure to EACCES
	This just regularizes the return code on uselib(2).

  exec: Move S_ISREG() check earlier
	This moves the S_ISREG() check even earlier than it was already.

  exec: Move path_noexec() check earlier
	This adds the path_noexec() check to the same place as the
	S_ISREG() check.

This patch (of 3):

Change uselib(2)' S_ISREG() error return to EACCES instead of EINVAL so
the behavior matches execve(2), and the seemingly documented value.  The
"not a regular file" failure mode of execve(2) is explicitly
documented[1], but it is not mentioned in uselib(2)[2] which does,
however, say that open(2) and mmap(2) errors may apply.  The documentation
for open(2) does not include a "not a regular file" error[3], but mmap(2)
does[4], and it is EACCES.

[1] http://man7.org/linux/man-pages/man2/execve.2.html#ERRORS
[2] http://man7.org/linux/man-pages/man2/uselib.2.html#ERRORS
[3] http://man7.org/linux/man-pages/man2/open.2.html#ERRORS
[4] http://man7.org/linux/man-pages/man2/mmap.2.html#ERRORSSigned-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: http://lkml.kernel.org/r/20200605160013.3954297-1-keescook@chromium.org
Link: http://lkml.kernel.org/r/20200605160013.3954297-2-keescook@chromium.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f38c85f1
...@@ -141,11 +141,10 @@ SYSCALL_DEFINE1(uselib, const char __user *, library) ...@@ -141,11 +141,10 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
if (IS_ERR(file)) if (IS_ERR(file))
goto out; goto out;
error = -EINVAL; error = -EACCES;
if (!S_ISREG(file_inode(file)->i_mode)) if (!S_ISREG(file_inode(file)->i_mode))
goto exit; goto exit;
error = -EACCES;
if (path_noexec(&file->f_path)) if (path_noexec(&file->f_path))
goto exit; goto exit;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment