mirror of
https://gitlab.alpinelinux.org/alpine/abuild.git
synced 2024-12-22 15:02:59 +00:00
442e804291
mini sudo that checks if user is in "abuild" group and allows it to run apk, adduser adn addgroup as root ref #951
82 lines
1.5 KiB
C
82 lines
1.5 KiB
C
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#include <sys/types.h>
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#include <err.h>
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#include <grp.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifndef ABUILD_GROUP
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#define ABUILD_GROUP "abuild"
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#endif
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static const char* valid_cmds[] = {
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"/bin/adduser",
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"/bin/addgroup",
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"/sbin/apk",
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NULL
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};
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const char *get_command_path(const char *cmd)
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{
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const char *p;
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int i;
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for (i = 0; valid_cmds[i] != NULL; i++) {
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p = strrchr(valid_cmds[i], '/') + 1;
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if (strcmp(p, cmd) == 0)
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return valid_cmds[i];
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}
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return NULL;
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}
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int is_in_group(gid_t group)
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{
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int ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
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gid_t *buf = malloc(ngroups_max * sizeof(gid_t));
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int ngroups, ret = 0;
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int i;
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if (buf == NULL) {
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perror("malloc");
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return 0;
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}
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ngroups = getgroups(ngroups_max, buf);
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for (i = 0; i < ngroups; i++) {
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if (buf[i] == group)
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break;
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}
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free(buf);
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return i < ngroups;
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}
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int main(int argc, const char *argv[])
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{
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struct group *grent;
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const char *cmd;
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const char *path;
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grent = getgrnam(ABUILD_GROUP);
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if (grent == NULL)
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errx(1, "%s: Group not found", ABUILD_GROUP);
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if (!is_in_group(grent->gr_gid))
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errx(1, "Not a member of group %s\n", ABUILD_GROUP);
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cmd = strrchr(argv[0], '-');
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if (cmd == NULL)
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errx(1, "Calling command has no '-'");
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cmd++;
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path = get_command_path(cmd);
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if (path == NULL)
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errx(1, "%s: Not a valid subcommand", cmd);
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argv[0] = path;
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/* set our uid to root soo bbsuid --install works */
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setuid(0);
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execv(path, (char * const*)argv);
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return 1;
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}
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