From: Christian Brauner <christian.brauner@ubuntu.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
bpf@vger.kernel.org
Cc: Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH 3/3] bpf: use copy_struct_from_user() in bpf() syscall
Date: Wed, 9 Oct 2019 18:09:07 +0200 [thread overview]
Message-ID: <20191009160907.10981-4-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20191009160907.10981-1-christian.brauner@ubuntu.com>
In v5.4-rc2 we added a new helper (cf. [1]) copy_struct_from_user().
This helper is intended for all codepaths that copy structs from
userspace that are versioned by size. The bpf() syscall does exactly
what copy_struct_from_user() is doing.
Note that copy_struct_from_user() is calling min() already. So
technically, the min_t() call could go. But the size is used further
below so leave it.
[1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
kernel/bpf/syscall.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 6f4f9097b1fe..6fdcbdb27501 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2819,14 +2819,11 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
return -EPERM;
- err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
- if (err)
- return err;
size = min_t(u32, size, sizeof(attr));
-
/* copy attributes from user space, may be less than sizeof(bpf_attr) */
- if (copy_from_user(&attr, uattr, size) != 0)
- return -EFAULT;
+ err = copy_struct_from_user(&attr, sizeof(attr), uattr, size);
+ if (err)
+ return err;
err = security_bpf(cmd, &attr, size);
if (err < 0)
--
2.23.0
next prev parent reply other threads:[~2019-10-09 16:09 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 16:09 [PATCH 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-09 16:09 ` [PATCH 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-10 10:50 ` Aleksa Sarai
2019-10-09 16:09 ` [PATCH 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-10 10:51 ` Aleksa Sarai
2019-10-09 16:09 ` Christian Brauner [this message]
2019-10-10 10:51 ` [PATCH 3/3] bpf: use copy_struct_from_user() in bpf() syscall Aleksa Sarai
2019-10-09 23:06 ` [PATCH 0/3] bpf: switch to new usercopy helpers Alexei Starovoitov
2019-10-10 9:26 ` Christian Brauner
2019-10-15 22:45 ` Alexei Starovoitov
2019-10-15 22:55 ` Christian Brauner
2019-10-15 23:02 ` Alexei Starovoitov
2019-10-15 23:08 ` Christian Brauner
2019-10-16 0:41 ` [PATCH v2 " Christian Brauner
2019-10-16 0:41 ` [PATCH v2 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 0:41 ` [PATCH v2 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 0:41 ` [PATCH v2 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 0:48 ` [PATCH v2 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-16 2:14 ` Alexei Starovoitov
2019-10-16 3:31 ` Christian Brauner
2019-10-16 3:44 ` [PATCH v3 " Christian Brauner
2019-10-16 3:44 ` [PATCH v3 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 5:23 ` Alexei Starovoitov
2019-10-16 3:44 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 5:25 ` Alexei Starovoitov
2019-10-16 7:30 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd()y Christian Brauner
2019-10-16 7:43 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 3:44 ` [PATCH v3 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 18:31 ` [PATCH bpf-next v4 0/3] bpf: switch to new usercopy helpers Alexei Starovoitov
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