diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-05-25 12:56:15 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-03 08:12:11 +0200 |
| commit | 63d6d52ec88b8b4cab9880036c42bb2a862784f3 (patch) | |
| tree | 85b7e4579d3b7d08369a3979928fb15679a0aab2 /security | |
| parent | ea30c3f00c87ed005c819114e3ab1832c589f9b3 (diff) | |
exec: Always set cap_ambient in cap_bprm_set_creds
[ Upstream commit a4ae32c71fe90794127b32d26d7ad795813b502e ]
An invariant of cap_bprm_set_creds is that every field in the new cred
structure that cap_bprm_set_creds might set, needs to be set every
time to ensure the fields does not get a stale value.
The field cap_ambient is not set every time cap_bprm_set_creds is
called, which means that if there is a suid or sgid script with an
interpreter that has neither the suid nor the sgid bits set the
interpreter should be able to accept ambient credentials.
Unfortuantely because cap_ambient is not reset to it's original value
the interpreter can not accept ambient credentials.
Given that the ambient capability set is expected to be controlled by
the caller, I don't think this is particularly serious. But it is
definitely worth fixing so the code works correctly.
I have tested to verify my reading of the code is correct and the
interpreter of a sgid can receive ambient capabilities with this
change and cannot receive ambient capabilities without this change.
Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>
Fixes: 58319057b784 ("capabilities: ambient capabilities")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/commoncap.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index 48071ed7c445..b62f97d83fd8 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -494,6 +494,7 @@ int cap_bprm_set_creds(struct linux_binprm *bprm) int ret; kuid_t root_uid; + new->cap_ambient = old->cap_ambient; if (WARN_ON(!cap_ambient_invariant_ok(old))) return -EPERM; |