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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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/*
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* Copyright © 2014 Canonical Ltd.
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*
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* This program is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 3, as published
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* by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranties of
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* MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Authors:
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* Ted Gould <ted.gould@canonical.com>
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*/
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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#define _POSIX_C_SOURCE 200809L
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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#include <stdlib.h> |
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#include <stdio.h> |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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#include <unistd.h> |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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#include <errno.h> |
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#include <string.h> |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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#include <fcntl.h> |
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#include <sys/stat.h> |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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int
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main (int argc, char * argv[]) |
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{
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if (argc != 3) { |
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168.3.6
by Ted Gould
No fancy printing libraries here |
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fprintf(stderr, "Usage: %s <pid> <value>\n", argv[0]); |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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}
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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/* Not we turn the pid into an integer and back so that we can ensure we don't
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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get used for nefarious tasks. */
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int pidval = atoi(argv[1]); |
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if ((pidval < 1) || (pidval >= 32768)) { |
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168.3.11
by Ted Gould
Remove argument strings from error messages |
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fprintf(stderr, "PID passed is invalid: %d\n", pidval); |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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}
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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/* Not we turn the oom value into an integer and back so that we can ensure we don't
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get used for nefarious tasks. */
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int oomval = atoi(argv[2]); |
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if ((oomval < -1000) || (oomval >= 1000)) { |
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fprintf(stderr, "OOM Value passed is invalid: %d\n", oomval); |
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exit(EXIT_FAILURE); |
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}
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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/* Open up the PID directory first, to ensure that it is actually one of
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ours, so that we can't be used to set a OOM value on just anything */
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char pidpath[32]; |
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snprintf(pidpath, sizeof(pidpath), "/proc/%d", pidval); |
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int piddir = open(pidpath, O_RDONLY | O_DIRECTORY); |
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if (piddir < 0) { |
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168.3.11
by Ted Gould
Remove argument strings from error messages |
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fprintf(stderr, "Unable open PID directory '%s' for '%d': %s\n", pidpath, pidval, strerror(errno)); |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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}
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struct stat piddirstat = {0}; |
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168.3.7
by Ted Gould
Bad check |
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if (fstat(piddir, &piddirstat) < 0) { |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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close(piddir); |
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168.3.11
by Ted Gould
Remove argument strings from error messages |
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fprintf(stderr, "Unable stat PID directory '%s' for '%d': %s\n", pidpath, pidval, strerror(errno)); |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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}
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if (getuid() != piddirstat.st_uid) { |
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close(piddir); |
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168.3.6
by Ted Gould
No fancy printing libraries here |
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fprintf(stderr, "PID directory '%s' is not owned by %d but by %d\n", pidpath, getuid(), piddirstat.st_uid); |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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}
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/* Looks good, let's try to get the actual oom_adj_score file to write
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the value to it. */
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int adj = openat(piddir, "oom_score_adj", O_WRONLY); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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int openerr = errno; |
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168.3.12
by Ted Gould
Check less that zero for open |
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if (adj < 0) { |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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close(piddir); |
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168.3.15
by Ted Gould
Fix return to be an exit |
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/* ENOENT happens a fair amount because of races, so it's not
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worth printing a warning about */
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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if (openerr != ENOENT) { |
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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fprintf(stderr, "Unable to set OOM value of '%d' on '%d': %s\n", oomval, pidval, strerror(openerr)); |
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168.3.15
by Ted Gould
Fix return to be an exit |
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exit(EXIT_FAILURE); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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} else { |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_SUCCESS); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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}
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}
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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char oomstring[32]; |
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snprintf(oomstring, sizeof(oomstring), "%d", oomval); |
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size_t writesize = write(adj, oomstring, strlen(oomstring)); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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int writeerr = errno; |
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168.3.5
by Ted Gould
Reset so that we're checking the directory first, use that directory that we have open. |
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close(adj); |
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close(piddir); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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if (writesize == strlen(oomstring)) |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_SUCCESS); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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if (writeerr != 0) |
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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fprintf(stderr, "Unable to set OOM value of '%d' on '%d': %s\n", oomval, pidval, strerror(writeerr)); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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else
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/* No error, but yet, wrong size. Not sure, what could cause this. */
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168.3.16
by Ted Gould
Parse and verify the OOM value as well |
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fprintf(stderr, "Unable to set OOM value of '%d' on '%d': Wrote %d bytes\n", oomval, pidval, (int)writesize); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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168.3.10
by Ted Gould
Use symbolic names for exit values |
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exit(EXIT_FAILURE); |
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168.3.2
by Ted Gould
Starting out a little helper to make setuid and help us if we don't have permissions <cough>oxide</cough> |
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}
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