diff --git a/ebpf/aya-ebpf/src/args.rs b/ebpf/aya-ebpf/src/args.rs index 72023e0d7..f6df22bdf 100644 --- a/ebpf/aya-ebpf/src/args.rs +++ b/ebpf/aya-ebpf/src/args.rs @@ -27,14 +27,17 @@ pub unsafe trait FromBtfArgument: Sized { /// memory. In particular, the value of `n` must not exceed the number of function /// arguments. Moreover, `ctx` must be a valid pointer to a BTF context, and `T` must /// be the right type for the given argument. - unsafe fn from_argument(ctx: *const c_void, n: usize) -> Self; + unsafe fn from_argument(ctx: *const c_void, n: usize) -> Option; } unsafe impl FromBtfArgument for *const T { - unsafe fn from_argument(ctx: *const c_void, n: usize) -> *const T { + unsafe fn from_argument(ctx: *const c_void, n: usize) -> Option { // BTF arguments are exposed as an array of `usize` where `usize` can // either be treated as a pointer or a primitive type - *(ctx as *const usize).add(n) as _ + // *(ctx as *const usize).add(n) as _ + bpf_probe_read((ctx as *const usize).add(n)) + .map(|v| v as *const _) + .ok() } } @@ -42,10 +45,10 @@ unsafe impl FromBtfArgument for *const T { macro_rules! unsafe_impl_from_btf_argument { ($type:ident) => { unsafe impl FromBtfArgument for $type { - unsafe fn from_argument(ctx: *const c_void, n: usize) -> Self { + unsafe fn from_argument(ctx: *const c_void, n: usize) -> Option { // BTF arguments are exposed as an array of `usize` where `usize` can // either be treated as a pointer or a primitive type - *(ctx as *const usize).add(n) as _ + Some(*(ctx as *const usize).add(n) as _) } } }; diff --git a/ebpf/aya-ebpf/src/programs/fentry.rs b/ebpf/aya-ebpf/src/programs/fentry.rs index af82ca7c9..6742553db 100644 --- a/ebpf/aya-ebpf/src/programs/fentry.rs +++ b/ebpf/aya-ebpf/src/programs/fentry.rs @@ -31,7 +31,7 @@ impl FEntryContext { /// Ok(0) /// } /// ``` - pub unsafe fn arg(&self, n: usize) -> T { + pub unsafe fn arg(&self, n: usize) -> Option { T::from_argument(self.ctx as *const _, n) } } diff --git a/ebpf/aya-ebpf/src/programs/fexit.rs b/ebpf/aya-ebpf/src/programs/fexit.rs index d97288329..0e2619027 100644 --- a/ebpf/aya-ebpf/src/programs/fexit.rs +++ b/ebpf/aya-ebpf/src/programs/fexit.rs @@ -31,7 +31,7 @@ impl FExitContext { /// Ok(0) /// } /// ``` - pub unsafe fn arg(&self, n: usize) -> T { + pub unsafe fn arg(&self, n: usize) -> Option { T::from_argument(self.ctx as *const _, n) } } diff --git a/ebpf/aya-ebpf/src/programs/lsm.rs b/ebpf/aya-ebpf/src/programs/lsm.rs index 0ad295904..53855e0fb 100644 --- a/ebpf/aya-ebpf/src/programs/lsm.rs +++ b/ebpf/aya-ebpf/src/programs/lsm.rs @@ -50,7 +50,7 @@ impl LsmContext { /// ``` /// /// [1]: https://elixir.bootlin.com/linux/latest/source/include/linux/lsm_hook_defs.h - pub unsafe fn arg(&self, n: usize) -> T { + pub unsafe fn arg(&self, n: usize) -> Option { T::from_argument(self.ctx as *const _, n) } } diff --git a/ebpf/aya-ebpf/src/programs/tp_btf.rs b/ebpf/aya-ebpf/src/programs/tp_btf.rs index 0c8a7991a..b4bd15760 100644 --- a/ebpf/aya-ebpf/src/programs/tp_btf.rs +++ b/ebpf/aya-ebpf/src/programs/tp_btf.rs @@ -40,7 +40,7 @@ impl BtfTracePointContext { /// ``` /// /// [1]: https://elixir.bootlin.com/linux/latest/source/include/linux/lsm_hook_defs.h - pub unsafe fn arg(&self, n: usize) -> T { + pub unsafe fn arg(&self, n: usize) -> Option { T::from_argument(self.ctx as *const _, n) } } diff --git a/test/integration-ebpf/Cargo.toml b/test/integration-ebpf/Cargo.toml index 6c550dae4..d44f9a1ad 100644 --- a/test/integration-ebpf/Cargo.toml +++ b/test/integration-ebpf/Cargo.toml @@ -25,6 +25,10 @@ path = "src/bpf_probe_read.rs" name = "log" path = "src/log.rs" +[[bin]] +name = "args" +path = "src/args.rs" + [[bin]] name = "map_test" path = "src/map_test.rs" diff --git a/test/integration-ebpf/src/args.rs b/test/integration-ebpf/src/args.rs new file mode 100644 index 000000000..f759f7f43 --- /dev/null +++ b/test/integration-ebpf/src/args.rs @@ -0,0 +1,33 @@ +#![no_std] +#![no_main] + +use aya_bpf::{ + cty::{c_long, c_longlong}, + macros::{fentry, kprobe}, + programs::{FEntryContext, ProbeContext}, +}; + +#[kprobe] +pub fn kprobe_vfs_write(ctx: ProbeContext) { + let _ = try_kprobe_vfs_write(ctx); +} + +fn try_kprobe_vfs_write(ctx: ProbeContext) -> Result<(), c_long> { + let _pos: *const c_longlong = ctx.arg(3).ok_or(1)?; + Ok(()) +} + +#[fentry] +pub fn fentry_vfs_write(ctx: FEntryContext) { + let _ = try_fentry_vfs_write(ctx); +} + +fn try_fentry_vfs_write(ctx: FEntryContext) -> Result<(), c_long> { + let _pos: *const c_longlong = unsafe { ctx.arg(3).ok_or(1)? }; + Ok(()) +} + +#[panic_handler] +fn panic(_info: &core::panic::PanicInfo) -> ! { + unsafe { core::hint::unreachable_unchecked() } +} diff --git a/test/integration-test/src/tests.rs b/test/integration-test/src/tests.rs index 4b5c8fcbb..b97c1b359 100644 --- a/test/integration-test/src/tests.rs +++ b/test/integration-test/src/tests.rs @@ -1,3 +1,4 @@ +mod args; mod bpf_probe_read; mod btf_relocations; mod elf; diff --git a/test/integration-test/src/tests/args.rs b/test/integration-test/src/tests/args.rs new file mode 100644 index 000000000..947ee4bac --- /dev/null +++ b/test/integration-test/src/tests/args.rs @@ -0,0 +1,34 @@ +use aya::{ + include_bytes_aligned, + programs::{FEntry, KProbe}, + Bpf, Btf, +}; + +use super::{integration_test, IntegrationTest}; + +#[integration_test] +fn kprobe_args() { + let bytes = include_bytes_aligned!("../../../../target/bpfel-unknown-none/debug/args"); + let mut bpf = Bpf::load(bytes).unwrap(); + let kprobe_vfs_write: &mut KProbe = bpf + .program_mut("kprobe_vfs_write") + .unwrap() + .try_into() + .unwrap(); + kprobe_vfs_write.load().unwrap(); + kprobe_vfs_write.attach("vfs_write", 0).unwrap(); +} + +#[integration_test] +fn fentry_args() { + let bytes = include_bytes_aligned!("../../../../target/bpfel-unknown-none/debug/args"); + let mut bpf = Bpf::load(bytes).unwrap(); + let fentry_vfs_write: &mut FEntry = bpf + .program_mut("fentry_vfs_write") + .unwrap() + .try_into() + .unwrap(); + let btf = Btf::from_sys_fs().unwrap(); + fentry_vfs_write.load("vfs_write", &btf).unwrap(); + fentry_vfs_write.attach().unwrap(); +}