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| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-03-22 23:46:24 +0300 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2020-05-20 22:45:31 +0300 |
| commit | b8bff599261c930630385ee21d3f98e7ce7d4843 (patch) | |
| tree | abe467d5124f1df78e2d2383068c90f518a16069 /fs/exec.c | |
| parent | 87b047d2be417b271d80f5e490a825c6fd53ecad (diff) | |
| download | linux-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.c | 6 |
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; |