diff options
| -rw-r--r-- | include/uapi/linux/if_xdp.h | 4 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 48 | ||||
| -rw-r--r-- | net/xdp/xdp_umem.c | 6 | ||||
| -rw-r--r-- | net/xdp/xsk.c | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/get_cgroup_id_kern.c | 14 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/get_cgroup_id_user.c | 12 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 58 |
7 files changed, 118 insertions, 26 deletions
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h index 1fa0e977ea8d..caed8b1614ff 100644 --- a/include/uapi/linux/if_xdp.h +++ b/include/uapi/linux/if_xdp.h @@ -63,8 +63,8 @@ struct xdp_statistics { /* Pgoff for mmaping the rings */ #define XDP_PGOFF_RX_RING 0 #define XDP_PGOFF_TX_RING 0x80000000 -#define XDP_UMEM_PGOFF_FILL_RING 0x100000000 -#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000 +#define XDP_UMEM_PGOFF_FILL_RING 0x100000000ULL +#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000ULL /* Rx/Tx descriptor */ struct xdp_desc { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d6403b5166f4..cced0c1e63e2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1617,6 +1617,30 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env, } #endif +static int check_ctx_reg(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg, int regno) +{ + /* Access to ctx or passing it to a helper is only allowed in + * its original, unmodified form. + */ + + if (reg->off) { + verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n", + regno, reg->off); + return -EACCES; + } + + if (!tnum_is_const(reg->var_off) || reg->var_off.value) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf); + return -EACCES; + } + + return 0; +} + /* truncate register to smaller size (in bytes) * must be called with size < BPF_REG_SIZE */ @@ -1686,24 +1710,11 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn verbose(env, "R%d leaks addr into ctx\n", value_regno); return -EACCES; } - /* ctx accesses must be at a fixed offset, so that we can - * determine what type of data were returned. - */ - if (reg->off) { - verbose(env, - "dereference of modified ctx ptr R%d off=%d+%d, ctx+const is allowed, ctx+const+const is not\n", - regno, reg->off, off - reg->off); - return -EACCES; - } - if (!tnum_is_const(reg->var_off) || reg->var_off.value) { - char tn_buf[48]; - tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); - verbose(env, - "variable ctx access var_off=%s off=%d size=%d", - tn_buf, off, size); - return -EACCES; - } + err = check_ctx_reg(env, reg, regno); + if (err < 0) + return err; + err = check_ctx_access(env, insn_idx, off, size, t, ®_type); if (!err && t == BPF_READ && value_regno >= 0) { /* ctx access returns either a scalar, or a @@ -1984,6 +1995,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, expected_type = PTR_TO_CTX; if (type != expected_type) goto err_type; + err = check_ctx_reg(env, reg, regno); + if (err < 0) + return err; } else if (arg_type_is_mem_ptr(arg_type)) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c index 7eb4948a38d2..b9ef487c4618 100644 --- a/net/xdp/xdp_umem.c +++ b/net/xdp/xdp_umem.c @@ -132,8 +132,10 @@ static void xdp_umem_unpin_pages(struct xdp_umem *umem) static void xdp_umem_unaccount_pages(struct xdp_umem *umem) { - atomic_long_sub(umem->npgs, &umem->user->locked_vm); - free_uid(umem->user); + if (umem->user) { + atomic_long_sub(umem->npgs, &umem->user->locked_vm); + free_uid(umem->user); + } } static void xdp_umem_release(struct xdp_umem *umem) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index c6ed2454f7ce..36919a254ba3 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -643,7 +643,7 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname, static int xsk_mmap(struct file *file, struct socket *sock, struct vm_area_struct *vma) { - unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; + loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT; unsigned long size = vma->vm_end - vma->vm_start; struct xdp_sock *xs = xdp_sk(sock->sk); struct xsk_queue *q = NULL; diff --git a/tools/testing/selftests/bpf/get_cgroup_id_kern.c b/tools/testing/selftests/bpf/get_cgroup_id_kern.c index 2cf8cb23f209..014dba10b8a5 100644 --- a/tools/testing/selftests/bpf/get_cgroup_id_kern.c +++ b/tools/testing/selftests/bpf/get_cgroup_id_kern.c @@ -11,12 +11,24 @@ struct bpf_map_def SEC("maps") cg_ids = { .max_entries = 1, }; +struct bpf_map_def SEC("maps") pidmap = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + SEC("tracepoint/syscalls/sys_enter_nanosleep") int trace(void *ctx) { - __u32 key = 0; + __u32 pid = bpf_get_current_pid_tgid(); + __u32 key = 0, *expected_pid; __u64 *val; + expected_pid = bpf_map_lookup_elem(&pidmap, &key); + if (!expected_pid || *expected_pid != pid) + return 0; + val = bpf_map_lookup_elem(&cg_ids, &key); if (val) *val = bpf_get_current_cgroup_id(); diff --git a/tools/testing/selftests/bpf/get_cgroup_id_user.c b/tools/testing/selftests/bpf/get_cgroup_id_user.c index ea19a42e5894..e8da7b39158d 100644 --- a/tools/testing/selftests/bpf/get_cgroup_id_user.c +++ b/tools/testing/selftests/bpf/get_cgroup_id_user.c @@ -50,13 +50,13 @@ int main(int argc, char **argv) const char *probe_name = "syscalls/sys_enter_nanosleep"; const char *file = "get_cgroup_id_kern.o"; int err, bytes, efd, prog_fd, pmu_fd; + int cgroup_fd, cgidmap_fd, pidmap_fd; struct perf_event_attr attr = {}; - int cgroup_fd, cgidmap_fd; struct bpf_object *obj; __u64 kcgid = 0, ucgid; + __u32 key = 0, pid; int exit_code = 1; char buf[256]; - __u32 key = 0; err = setup_cgroup_environment(); if (CHECK(err, "setup_cgroup_environment", "err %d errno %d\n", err, @@ -81,6 +81,14 @@ int main(int argc, char **argv) cgidmap_fd, errno)) goto close_prog; + pidmap_fd = bpf_find_map(__func__, obj, "pidmap"); + if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", + pidmap_fd, errno)) + goto close_prog; + + pid = getpid(); + bpf_map_update_elem(pidmap_fd, &key, &pid, 0); + snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%s/id", probe_name); efd = open(buf, O_RDONLY, 0); diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 7cb1d74057ce..2ecd27b670d7 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -8647,7 +8647,7 @@ static struct bpf_test tests[] = { offsetof(struct __sk_buff, mark)), BPF_EXIT_INSN(), }, - .errstr = "dereference of modified ctx ptr R1 off=68+8, ctx+const is allowed, ctx+const+const is not", + .errstr = "dereference of modified ctx ptr", .result = REJECT, .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, @@ -12258,6 +12258,62 @@ static struct bpf_test tests[] = { .result = ACCEPT, .retval = 5, }, + { + "pass unmodified ctx pointer to helper", + .insns = { + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_csum_update), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + }, + { + "pass modified ctx pointer to helper, 1", + .insns = { + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -612), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_csum_update), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = REJECT, + .errstr = "dereference of modified ctx ptr", + }, + { + "pass modified ctx pointer to helper, 2", + .insns = { + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -612), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_get_socket_cookie), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result_unpriv = REJECT, + .result = REJECT, + .errstr_unpriv = "dereference of modified ctx ptr", + .errstr = "dereference of modified ctx ptr", + }, + { + "pass modified ctx pointer to helper, 3", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, 0), + BPF_ALU64_IMM(BPF_AND, BPF_REG_3, 4), + BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_csum_update), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = REJECT, + .errstr = "variable ctx access var_off=(0x0; 0x4)", + }, }; static int probe_filter_length(const struct bpf_insn *fp) |