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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/testing/selftests/bpf/cap_helpers.c
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// SPDX-License-Identifier: GPL-2.0

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#include "cap_helpers.h"

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/* Avoid including <sys/capability.h> from the libcap-devel package,

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 * so directly declare them here and use them from glibc.

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 */

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int capget(cap_user_header_t header, cap_user_data_t data);

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int capset(cap_user_header_t header, const cap_user_data_t data);

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int cap_enable_effective(__u64 caps, __u64 *old_caps)

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{

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	struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];

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	struct __user_cap_header_struct hdr = {

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		.version = _LINUX_CAPABILITY_VERSION_3,

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	};

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	__u32 cap0 = caps;

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	__u32 cap1 = caps >> 32;

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	int err;

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	err = capget(&hdr, data);

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	if (err)

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		return -errno;

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	if (old_caps)

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		*old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;

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	if ((data[0].effective & cap0) == cap0 &&

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	    (data[1].effective & cap1) == cap1)

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		return 0;

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	data[0].effective |= cap0;

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	data[1].effective |= cap1;

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	err = capset(&hdr, data);

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	if (err)

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		return -errno;

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	return 0;

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}

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int cap_disable_effective(__u64 caps, __u64 *old_caps)

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{

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	struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];

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	struct __user_cap_header_struct hdr = {

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		.version = _LINUX_CAPABILITY_VERSION_3,

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	};

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	__u32 cap0 = caps;

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	__u32 cap1 = caps >> 32;

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	int err;

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	err = capget(&hdr, data);

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	if (err)

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		return -errno;

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	if (old_caps)

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		*old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;

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	if (!(data[0].effective & cap0) && !(data[1].effective & cap1))

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		return 0;

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	data[0].effective &= ~cap0;

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	data[1].effective &= ~cap1;

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	err = capset(&hdr, data);

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	if (err)

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		return -errno;

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	return 0;

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}

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