Commit 9ffccb76 authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Daniel Borkmann

selftests/bpf: Test narrow load from bpf_sysctl.write

There are tests for full and narrows loads from bpf_sysctl.file_pos, but
for bpf_sysctl.write only full load is tested. Add the missing test.
Suggested-by: default avatarAndrey Ignatov <rdna@fb.com>
Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20191029143027.28681-1-iii@linux.ibm.com
parent 15ab09bd
......@@ -120,6 +120,29 @@ static struct sysctl_test tests[] = {
.newval = "(none)", /* same as default, should fail anyway */
.result = OP_EPERM,
},
{
.descr = "ctx:write sysctl:write read ok narrow",
.insns = {
/* u64 w = (u16)write & 1; */
#if __BYTE_ORDER == __LITTLE_ENDIAN
BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_1,
offsetof(struct bpf_sysctl, write)),
#else
BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_1,
offsetof(struct bpf_sysctl, write) + 2),
#endif
BPF_ALU64_IMM(BPF_AND, BPF_REG_7, 1),
/* return 1 - w; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_7),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "kernel/domainname",
.open_flags = O_WRONLY,
.newval = "(none)", /* same as default, should fail anyway */
.result = OP_EPERM,
},
{
.descr = "ctx:write sysctl:read write reject",
.insns = {
......
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