[PATCH bpf-next] bpf: check flags in 'bpf_ringbuf_discard()' and 'bpf_ringbuf_submit()'
From: Pedro Tammela <hidden>
Date: 2021-03-28 16:13:06
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [ringbuf], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
The current code only checks flags in 'bpf_ringbuf_output()'. Signed-off-by: Pedro Tammela <redacted> --- include/uapi/linux/bpf.h | 8 ++++---- kernel/bpf/ringbuf.c | 13 +++++++++++-- tools/include/uapi/linux/bpf.h | 8 ++++---- 3 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 100cb2e4c104..232b5e5dd045 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -4073,7 +4073,7 @@ union bpf_attr { * Valid pointer with *size* bytes of memory available; NULL, * otherwise. * - * void bpf_ringbuf_submit(void *data, u64 flags) + * int bpf_ringbuf_submit(void *data, u64 flags) * Description * Submit reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
@@ -4083,9 +4083,9 @@ union bpf_attr { * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return - * Nothing. Always succeeds. + * 0 on success, or a negative error in case of failure. * - * void bpf_ringbuf_discard(void *data, u64 flags) + * int bpf_ringbuf_discard(void *data, u64 flags) * Description * Discard reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
@@ -4095,7 +4095,7 @@ union bpf_attr { * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return - * Nothing. Always succeeds. + * 0 on success, or a negative error in case of failure. * * u64 bpf_ringbuf_query(void *ringbuf, u64 flags) * Description
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
index f25b719ac786..f76dafe2427e 100644
--- a/kernel/bpf/ringbuf.c
+++ b/kernel/bpf/ringbuf.c@@ -397,26 +397,35 @@ static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard) BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags) { + if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP))) + return -EINVAL; + bpf_ringbuf_commit(sample, flags, false /* discard */); + return 0; } const struct bpf_func_proto bpf_ringbuf_submit_proto = { .func = bpf_ringbuf_submit, - .ret_type = RET_VOID, + .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_ALLOC_MEM, .arg2_type = ARG_ANYTHING, }; BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags) { + + if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP))) + return -EINVAL; + bpf_ringbuf_commit(sample, flags, true /* discard */); + return 0; } const struct bpf_func_proto bpf_ringbuf_discard_proto = { .func = bpf_ringbuf_discard, - .ret_type = RET_VOID, + .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_ALLOC_MEM, .arg2_type = ARG_ANYTHING, };
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 3d6d324184c0..d19c8c2688a2 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -4073,7 +4073,7 @@ union bpf_attr { * Valid pointer with *size* bytes of memory available; NULL, * otherwise. * - * void bpf_ringbuf_submit(void *data, u64 flags) + * int bpf_ringbuf_submit(void *data, u64 flags) * Description * Submit reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
@@ -4083,9 +4083,9 @@ union bpf_attr { * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return - * Nothing. Always succeeds. + * 0 on success, or a negative error in case of failure. * - * void bpf_ringbuf_discard(void *data, u64 flags) + * int bpf_ringbuf_discard(void *data, u64 flags) * Description * Discard reserved ring buffer sample, pointed to by *data*. * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
@@ -4095,7 +4095,7 @@ union bpf_attr { * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification * of new data availability is sent unconditionally. * Return - * Nothing. Always succeeds. + * 0 on success, or a negative error in case of failure. * * u64 bpf_ringbuf_query(void *ringbuf, u64 flags) * Description
--
2.25.1