commit 82e5d8cc768b0c7b03c551a9ab1f8f3f68d5f83f upstream.
gcc-11 introdces a harmless warning for cap_inode_getsecurity:
security/commoncap.c: In function ‘cap_inode_getsecurity’:
security/commoncap.c:440:33: error: ‘memcpy’ reading 16 bytes from a region of size 0 [-Werror=stringop-overread]
440 | memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The problem here is that tmpbuf is initialized to NULL, so gcc assumes
it is not accessible unless it gets set by vfs_getxattr_alloc(). This is
a legitimate warning as far as I can tell, but the code is correct since
it correctly handles the error when that function fails.
Add a separate NULL check to tell gcc about it as well.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
Cc: Andrey Zhizhikin <andrey.z@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3b0c2d3eaa83da259d7726192cf55a137769012f upstream.
It turns out that there are in fact userspace implementations that
care and this recent change caused a regression.
https://github.com/containers/buildah/issues/3071
As the motivation for the original change was future development,
and the impact is existing real world code just revert this change
and allow the ambiguity in v3 file caps.
Cc: stable@vger.kernel.org
Fixes: 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities")
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 95ebabde382c371572297915b104e55403674e73 ]
The v3 file capabilities have a uid field that records the filesystem
uid of the root user of the user namespace the file capabilities are
valid in.
When someone is silly enough to have the same underlying uid as the
root uid of multiple nested containers a v3 filesystem capability can
be ambiguous.
In the spirit of don't do that then, forbid writing a v3 filesystem
capability if it is ambiguous.
Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
Reviewed-by: Andrew G. Morgan <morgan@kernel.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f2b00be488730522d0fb7a8a5de663febdcefe0a ]
If a capability is stored on disk in v2 format cap_inode_getsecurity() will
currently return in v2 format unconditionally.
This is wrong: v2 cap should be equivalent to a v3 cap with zero rootid,
and so the same conversions performed on it.
If the rootid cannot be mapped, v3 is returned unconverted. Fix this so
that both v2 and v3 return -EOVERFLOW if the rootid (or the owner of the fs
user namespace in case of v2) cannot be mapped into the current user
namespace.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ 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>
Arnd Bergmann