Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
50 lines
1.2 KiB
C
50 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Capability utilities
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*/
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#include "cap.h"
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#include "debug.h"
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#include <errno.h>
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#include <string.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#define MAX_LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
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bool perf_cap__capable(int cap, bool *used_root)
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{
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struct __user_cap_header_struct header = {
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.version = _LINUX_CAPABILITY_VERSION_3,
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.pid = 0,
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};
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struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {};
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__u32 cap_val;
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*used_root = false;
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while (syscall(SYS_capget, &header, &data[0]) == -1) {
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/* Retry, first attempt has set the header.version correctly. */
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if (errno == EINVAL && header.version != _LINUX_CAPABILITY_VERSION_3 &&
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header.version == _LINUX_CAPABILITY_VERSION_1)
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continue;
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pr_debug2("capget syscall failed (%s - %d) fall back on root check\n",
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strerror(errno), errno);
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*used_root = true;
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return geteuid() == 0;
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}
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/* Extract the relevant capability bit. */
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if (cap >= 32) {
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if (header.version == _LINUX_CAPABILITY_VERSION_3) {
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cap_val = data[1].effective;
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} else {
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/* Capability beyond 32 is requested but only 32 are supported. */
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return false;
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}
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} else {
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cap_val = data[0].effective;
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}
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return (cap_val & (1 << (cap & 0x1f))) != 0;
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}
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