From f8d3da4ef8faf027261e06b7864583930dd7c7b9 Mon Sep 17 00:00:00 2001 From: Joanne Koong Date: Wed, 6 Jul 2022 16:25:47 -0700 Subject: bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIs Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write") added the bpf_dynptr_write() and bpf_dynptr_read() APIs. However, it will be needed for some dynptr types to pass in flags as well (e.g. when writing to a skb, the user may like to invalidate the hash or recompute the checksum). This patch adds a "u64 flags" arg to the bpf_dynptr_read() and bpf_dynptr_write() APIs before their UAPI signature freezes where we then cannot change them anymore with a 5.19.x released kernel. Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write") Signed-off-by: Joanne Koong Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20220706232547.4016651-1-joannelkoong@gmail.com --- include/uapi/linux/bpf.h | 11 +++++++---- kernel/bpf/helpers.c | 12 ++++++++---- tools/include/uapi/linux/bpf.h | 11 +++++++---- tools/testing/selftests/bpf/progs/dynptr_fail.c | 10 +++++----- tools/testing/selftests/bpf/progs/dynptr_success.c | 4 ++-- 5 files changed, 29 insertions(+), 19 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f4009dbdf62d..ef78e0e1a754 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5222,22 +5222,25 @@ union bpf_attr { * Return * Nothing. Always succeeds. * - * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset) + * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags) * Description * Read *len* bytes from *src* into *dst*, starting from *offset* * into *src*. + * *flags* is currently unused. * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length - * of *src*'s data, -EINVAL if *src* is an invalid dynptr. + * of *src*'s data, -EINVAL if *src* is an invalid dynptr or if + * *flags* is not 0. * - * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len) + * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags) * Description * Write *len* bytes from *src* into *dst*, starting from *offset* * into *dst*. + * *flags* is currently unused. * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length * of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst* - * is a read-only dynptr. + * is a read-only dynptr or if *flags* is not 0. * * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len) * Description diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 225806a02efb..bb1254f07667 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1497,11 +1497,12 @@ const struct bpf_func_proto bpf_dynptr_from_mem_proto = { .arg4_type = ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT, }; -BPF_CALL_4(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src, u32, offset) +BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, struct bpf_dynptr_kern *, src, + u32, offset, u64, flags) { int err; - if (!src->data) + if (!src->data || flags) return -EINVAL; err = bpf_dynptr_check_off_len(src, offset, len); @@ -1521,13 +1522,15 @@ const struct bpf_func_proto bpf_dynptr_read_proto = { .arg2_type = ARG_CONST_SIZE_OR_ZERO, .arg3_type = ARG_PTR_TO_DYNPTR, .arg4_type = ARG_ANYTHING, + .arg5_type = ARG_ANYTHING, }; -BPF_CALL_4(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src, u32, len) +BPF_CALL_5(bpf_dynptr_write, struct bpf_dynptr_kern *, dst, u32, offset, void *, src, + u32, len, u64, flags) { int err; - if (!dst->data || bpf_dynptr_is_rdonly(dst)) + if (!dst->data || flags || bpf_dynptr_is_rdonly(dst)) return -EINVAL; err = bpf_dynptr_check_off_len(dst, offset, len); @@ -1547,6 +1550,7 @@ const struct bpf_func_proto bpf_dynptr_write_proto = { .arg2_type = ARG_ANYTHING, .arg3_type = ARG_PTR_TO_MEM | MEM_RDONLY, .arg4_type = ARG_CONST_SIZE_OR_ZERO, + .arg5_type = ARG_ANYTHING, }; BPF_CALL_3(bpf_dynptr_data, struct bpf_dynptr_kern *, ptr, u32, offset, u32, len) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index f4009dbdf62d..ef78e0e1a754 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -5222,22 +5222,25 @@ union bpf_attr { * Return * Nothing. Always succeeds. * - * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset) + * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags) * Description * Read *len* bytes from *src* into *dst*, starting from *offset* * into *src*. + * *flags* is currently unused. * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length - * of *src*'s data, -EINVAL if *src* is an invalid dynptr. + * of *src*'s data, -EINVAL if *src* is an invalid dynptr or if + * *flags* is not 0. * - * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len) + * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags) * Description * Write *len* bytes from *src* into *dst*, starting from *offset* * into *dst*. + * *flags* is currently unused. * Return * 0 on success, -E2BIG if *offset* + *len* exceeds the length * of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst* - * is a read-only dynptr. + * is a read-only dynptr or if *flags* is not 0. * * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len) * Description diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c index d811cff73597..0a26c243e6e9 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_fail.c +++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c @@ -140,12 +140,12 @@ int use_after_invalid(void *ctx) bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(read_data), 0, &ptr); - bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0); + bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0); bpf_ringbuf_submit_dynptr(&ptr, 0); /* this should fail */ - bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0); + bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0); return 0; } @@ -338,7 +338,7 @@ int invalid_helper2(void *ctx) get_map_val_dynptr(&ptr); /* this should fail */ - bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0); + bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0, 0); return 0; } @@ -377,7 +377,7 @@ int invalid_write2(void *ctx) memcpy((void *)&ptr + 8, &x, sizeof(x)); /* this should fail */ - bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0); + bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0); bpf_ringbuf_submit_dynptr(&ptr, 0); @@ -473,7 +473,7 @@ int invalid_read2(void *ctx) get_map_val_dynptr(&ptr); /* this should fail */ - bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 1, 0); + bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 1, 0, 0); return 0; } diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c index d67be48df4b2..a3a6103c8569 100644 --- a/tools/testing/selftests/bpf/progs/dynptr_success.c +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c @@ -43,10 +43,10 @@ int test_read_write(void *ctx) bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr); /* Write data into the dynptr */ - err = err ?: bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data)); + err = bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0); /* Read the data that was written into the dynptr */ - err = err ?: bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0); + err = err ?: bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0); /* Ensure the data we read matches the data we wrote */ for (i = 0; i < sizeof(read_data); i++) { -- cgit v1.2.3