fix(driver): drop EF_USES_FD and EF_MODIFIES_STATE flags for enter events generated by uring syscalls

[alacuku]

Signed-off-by: Aldo Lacuku <aldo@lacuku.eu>

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

/kind cleanup

/kind design

/kind documentation

/kind failing-test

/kind feature

Any specific area of the project related to this PR?

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/area build

/area driver-kmod

/area driver-bpf

/area driver-modern-bpf

/area libscap-engine-bpf

/area libscap-engine-gvisor

/area libscap-engine-kmod

/area libscap-engine-modern-bpf

/area libscap-engine-nodriver

/area libscap-engine-noop

/area libscap-engine-source-plugin

/area libscap-engine-udig

/area libscap

/area libsinsp

/area tests

/area proposals

What this PR does / why we need it:
This PR prevents libs from crashing when handling events generated by io_uring_enter and io_uring_register syscalls.

Which issue(s) this PR fixes:

Fixes #
When Falco is running with -A option enabled and receives events generated by io_uring_enter and io_uring_register syscalls it crashes with the following error:

Runtime error: vector::_M_range_check: __n (which is 0) >= this->size() (which is 0). Exiting.

That is because ENTER events for the io_uring_enter and io_uring_register syscalls presented the EF_USES_FD flag. When the flag is set the libsinsp tries to extract the file descriptor from the event:

libs/userspace/libsinsp/parsers.cpp

Lines 689 to 703 in afca72c

	if(eflags & EF_USES_FD)
	{
	sinsp_evt_param *parinfo;
	//
	// Get the fd.
	// The fd is always the first parameter of the enter event.
	//
	parinfo = evt->get_param(0);
	ASSERT(parinfo->m_len == sizeof(int64_t));
	ASSERT(evt->get_param_info(0)->type == PT_FD);
	evt->m_tinfo->m_lastevent_fd = *(int64_t *)parinfo->m_val;
	evt->m_fdinfo = evt->m_tinfo->get_fd(evt->m_tinfo->m_lastevent_fd);
	}

Since the event does not have any parameters and we are trying to access the first one it causes a runtime error.

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

fix(driver): drop EF_USES_FD and EF_MODIFIES_STATE flags for enter events generated by uring syscalls

[poiana]

Hi @alacuku. Thanks for your PR.

I'm waiting for a falcosecurity member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[Andreagit97]

Thank you @alacuku!
/ok-to-test

[Andreagit97]

/approve

[poiana]

LGTM label has been added.

Git tree hash: 448103615648e28f32b96defd46887a5691f88b7

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alacuku, Andreagit97

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[FedeDP]

Great catch, thank you!

[FedeDP]

/test build-libs-bundled-deps