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authorEric W. Biederman <ebiederm@xmission.com>2020-03-22 23:46:24 +0300
committerEric W. Biederman <ebiederm@xmission.com>2020-05-20 22:45:31 +0300
commitb8bff599261c930630385ee21d3f98e7ce7d4843 (patch)
treeabe467d5124f1df78e2d2383068c90f518a16069 /fs/exec.c
parent87b047d2be417b271d80f5e490a825c6fd53ecad (diff)
downloadlinux-b8bff599261c930630385ee21d3f98e7ce7d4843.tar.xz
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
Today security_bprm_set_creds has several implementations: apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds, smack_bprm_set_creds, and tomoyo_bprm_set_creds. Except for cap_bprm_set_creds they all test bprm->called_set_creds and return immediately if it is true. The function cap_bprm_set_creds ignores bprm->calld_sed_creds entirely. Create a new LSM hook security_bprm_creds_for_exec that is called just before prepare_binprm in __do_execve_file, resulting in a LSM hook that is called exactly once for the entire of exec. Modify the bits of security_bprm_set_creds that only want to be called once per exec into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds behind. Remove bprm->called_set_creds all of it's former users have been moved to security_bprm_creds_for_exec. Add or upate comments a appropriate to bring them up to date and to reflect this change. Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 14b786158aa9..9e70da47f8d9 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1640,7 +1640,6 @@ int prepare_binprm(struct linux_binprm *bprm)
retval = security_bprm_set_creds(bprm);
if (retval)
return retval;
- bprm->called_set_creds = 1;
memset(bprm->buf, 0, BINPRM_BUF_SIZE);
return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
@@ -1855,6 +1854,11 @@ static int __do_execve_file(int fd, struct filename *filename,
if (retval < 0)
goto out;
+ /* Set the unchanging part of bprm->cred */
+ retval = security_bprm_creds_for_exec(bprm);
+ if (retval)
+ goto out;
+
retval = prepare_binprm(bprm);
if (retval < 0)
goto out;