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a5384c4267
As there are duplicated kernel headers in tools/include libc can pick
up the wrong definitions. This was causing the wrong system call for
capget in perf.
Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: e25ebda78e ("perf cap: Tidy up and improve capability testing")
Closes: https://lore.kernel.org/lkml/cc7d6bdf-1aeb-4179-9029-4baf50b59342@intel.com/
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241026055448.312247-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
51 lines
1.3 KiB
C
51 lines
1.3 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 <linux/capability.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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