| Message ID | 875zdajhj8.fsf@x220.int.ebiederm.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/7] binfmt: Move install_exec_creds after setup_new_exec to match binfmt_elf | expand |
On Tue, May 05, 2020 at 02:41:47PM -0500, Eric W. Biederman wrote: > > With install_exec_creds updated to follow immediately after > setup_new_exec, the failure of unshare_sighand is the only > code path where exec_update_mutex is held but not explicitly > unlocked. > > Update that code path to explicitly unlock exec_update_mutex. > > Remove the unlocking of exec_update_mutex from free_bprm. > > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/fs/exec.c b/fs/exec.c index 06b4c550af5d..6bd82a007bfc 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1344,7 +1344,7 @@ int flush_old_exec(struct linux_binprm * bprm) */ retval = unshare_sighand(me); if (retval) - goto out; + goto out_unlock; set_fs(USER_DS); me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | @@ -1361,6 +1361,8 @@ int flush_old_exec(struct linux_binprm * bprm) do_close_on_exec(me->files); return 0; +out_unlock: + mutex_unlock(&me->signal->exec_update_mutex); out: return retval; } @@ -1477,8 +1479,6 @@ static void free_bprm(struct linux_binprm *bprm) { free_arg_pages(bprm); if (bprm->cred) { - if (bprm->called_exec_mmap) - mutex_unlock(¤t->signal->exec_update_mutex); mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index a345d9fed3d8..6f564b9ad882 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -47,8 +47,7 @@ struct linux_binprm { secureexec:1, /* * Set by flush_old_exec, when exec_mmap has been called. - * This is past the point of no return, when the - * exec_update_mutex has been taken. + * This is past the point of no return. */ called_exec_mmap:1; #ifdef __alpha__
With install_exec_creds updated to follow immediately after setup_new_exec, the failure of unshare_sighand is the only code path where exec_update_mutex is held but not explicitly unlocked. Update that code path to explicitly unlock exec_update_mutex. Remove the unlocking of exec_update_mutex from free_bprm. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> --- fs/exec.c | 6 +++--- include/linux/binfmts.h | 3 +-- 2 files changed, 4 insertions(+), 5 deletions(-)