| /* |
| * Copyright (c) 2011, Comtrol Corp. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #include "defs.h" |
| #include <sys/param.h> |
| #include <poll.h> |
| |
| #include "syscall.h" |
| |
| const char **paths_selected = NULL; |
| static unsigned num_selected = 0; |
| |
| /* |
| * Return true if specified path matches one that we're tracing. |
| */ |
| static int |
| pathmatch(const char *path) |
| { |
| unsigned i; |
| |
| for (i = 0; i < num_selected; ++i) { |
| if (strcmp(path, paths_selected[i]) == 0) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * Return true if specified path (in user-space) matches. |
| */ |
| static int |
| upathmatch(struct tcb *tcp, unsigned long upath) |
| { |
| char path[PATH_MAX + 1]; |
| |
| return umovestr(tcp, upath, sizeof path, path) > 0 && |
| pathmatch(path); |
| } |
| |
| /* |
| * Return true if specified fd maps to a path we're tracing. |
| */ |
| static int |
| fdmatch(struct tcb *tcp, int fd) |
| { |
| char path[PATH_MAX + 1]; |
| int n = getfdpath(tcp, fd, path, sizeof(path)); |
| |
| return n >= 0 && pathmatch(path); |
| } |
| |
| /* |
| * Add a path to the set we're tracing. |
| * Specifying NULL will delete all paths. |
| */ |
| static void |
| storepath(const char *path) |
| { |
| unsigned i; |
| |
| if (pathmatch(path)) |
| return; /* already in table */ |
| |
| i = num_selected++; |
| paths_selected = xreallocarray(paths_selected, num_selected, |
| sizeof(paths_selected[0])); |
| paths_selected[i] = path; |
| } |
| |
| /* |
| * Get path associated with fd. |
| */ |
| int |
| getfdpath(struct tcb *tcp, int fd, char *buf, unsigned bufsize) |
| { |
| char linkpath[sizeof("/proc/%u/fd/%u") + 2 * sizeof(int)*3]; |
| ssize_t n; |
| |
| if (fd < 0) |
| return -1; |
| |
| sprintf(linkpath, "/proc/%u/fd/%u", tcp->pid, fd); |
| n = readlink(linkpath, buf, bufsize - 1); |
| /* |
| * NB: if buf is too small, readlink doesn't fail, |
| * it returns truncated result (IOW: n == bufsize - 1). |
| */ |
| if (n >= 0) |
| buf[n] = '\0'; |
| return n; |
| } |
| |
| /* |
| * Add a path to the set we're tracing. Also add the canonicalized |
| * version of the path. Secifying NULL will delete all paths. |
| */ |
| void |
| pathtrace_select(const char *path) |
| { |
| char *rpath; |
| |
| storepath(path); |
| |
| rpath = realpath(path, NULL); |
| |
| if (rpath == NULL) |
| return; |
| |
| /* if realpath and specified path are same, we're done */ |
| if (strcmp(path, rpath) == 0) { |
| free(rpath); |
| return; |
| } |
| |
| error_msg("Requested path '%s' resolved into '%s'", path, rpath); |
| storepath(rpath); |
| } |
| |
| /* |
| * Return true if syscall accesses a selected path |
| * (or if no paths have been specified for tracing). |
| */ |
| int |
| pathtrace_match(struct tcb *tcp) |
| { |
| const struct_sysent *s; |
| |
| s = tcp->s_ent; |
| |
| if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK))) |
| return 0; |
| |
| /* |
| * Check for special cases where we need to do something |
| * other than test arg[0]. |
| */ |
| |
| switch (s->sen) { |
| case SEN_dup2: |
| case SEN_dup3: |
| case SEN_sendfile: |
| case SEN_sendfile64: |
| case SEN_tee: |
| /* fd, fd */ |
| return fdmatch(tcp, tcp->u_arg[0]) || |
| fdmatch(tcp, tcp->u_arg[1]); |
| |
| case SEN_faccessat: |
| case SEN_fchmodat: |
| case SEN_fchownat: |
| case SEN_futimesat: |
| case SEN_inotify_add_watch: |
| case SEN_mkdirat: |
| case SEN_mknodat: |
| case SEN_newfstatat: |
| case SEN_openat: |
| case SEN_pipe2: |
| case SEN_readlinkat: |
| case SEN_unlinkat: |
| case SEN_utimensat: |
| /* fd, path */ |
| return fdmatch(tcp, tcp->u_arg[0]) || |
| upathmatch(tcp, tcp->u_arg[1]); |
| |
| case SEN_link: |
| case SEN_mount: |
| case SEN_pivotroot: |
| /* path, path */ |
| return upathmatch(tcp, tcp->u_arg[0]) || |
| upathmatch(tcp, tcp->u_arg[1]); |
| |
| case SEN_quotactl: |
| /* x, path */ |
| return upathmatch(tcp, tcp->u_arg[1]); |
| |
| case SEN_linkat: |
| case SEN_renameat2: |
| case SEN_renameat: |
| /* fd, path, fd, path */ |
| return fdmatch(tcp, tcp->u_arg[0]) || |
| fdmatch(tcp, tcp->u_arg[2]) || |
| upathmatch(tcp, tcp->u_arg[1]) || |
| upathmatch(tcp, tcp->u_arg[3]); |
| |
| case SEN_old_mmap: |
| #if defined(S390) |
| case SEN_old_mmap_pgoff: |
| #endif |
| case SEN_mmap: |
| case SEN_mmap_4koff: |
| case SEN_mmap_pgoff: |
| /* x, x, x, x, fd */ |
| return fdmatch(tcp, tcp->u_arg[4]); |
| |
| case SEN_symlinkat: |
| /* path, fd, path */ |
| return fdmatch(tcp, tcp->u_arg[1]) || |
| upathmatch(tcp, tcp->u_arg[0]) || |
| upathmatch(tcp, tcp->u_arg[2]); |
| |
| case SEN_splice: |
| /* fd, x, fd, x, x */ |
| return fdmatch(tcp, tcp->u_arg[0]) || |
| fdmatch(tcp, tcp->u_arg[2]); |
| |
| case SEN_epoll_ctl: |
| /* x, x, fd, x */ |
| return fdmatch(tcp, tcp->u_arg[2]); |
| |
| |
| case SEN_fanotify_mark: |
| /* x, x, x, fd, path */ |
| return fdmatch(tcp, tcp->u_arg[3]) || |
| upathmatch(tcp, tcp->u_arg[4]); |
| |
| case SEN_oldselect: |
| case SEN_pselect6: |
| case SEN_select: |
| { |
| int i, j; |
| int nfds; |
| long *args, oldargs[5]; |
| unsigned fdsize; |
| fd_set *fds; |
| |
| args = tcp->u_arg; |
| if (SEN_oldselect == s->sen) { |
| if (umoven(tcp, tcp->u_arg[0], sizeof oldargs, |
| oldargs) < 0) |
| { |
| error_msg("umoven() failed"); |
| return 0; |
| } |
| args = oldargs; |
| } |
| |
| /* Kernel truncates arg[0] to int, we do the same. */ |
| nfds = (int) args[0]; |
| /* Kernel rejects negative nfds, so we don't parse it either. */ |
| if (nfds <= 0) |
| return 0; |
| /* Beware of select(2^31-1, NULL, NULL, NULL) and similar... */ |
| if (nfds > 1024*1024) |
| nfds = 1024*1024; |
| fdsize = (((nfds + 7) / 8) + current_wordsize-1) & -current_wordsize; |
| fds = xmalloc(fdsize); |
| |
| for (i = 1; i <= 3; ++i) { |
| if (args[i] == 0) |
| continue; |
| if (umoven(tcp, args[i], fdsize, fds) < 0) { |
| error_msg("umoven() failed"); |
| continue; |
| } |
| for (j = 0;; j++) { |
| j = next_set_bit(fds, j, nfds); |
| if (j < 0) |
| break; |
| if (fdmatch(tcp, j)) { |
| free(fds); |
| return 1; |
| } |
| } |
| } |
| free(fds); |
| return 0; |
| } |
| |
| case SEN_poll: |
| case SEN_ppoll: |
| { |
| struct pollfd fds; |
| unsigned nfds; |
| unsigned long start, cur, end; |
| |
| start = tcp->u_arg[0]; |
| nfds = tcp->u_arg[1]; |
| |
| end = start + sizeof(fds) * nfds; |
| |
| if (nfds == 0 || end < start) |
| return 0; |
| |
| for (cur = start; cur < end; cur += sizeof(fds)) |
| if ((umoven(tcp, cur, sizeof fds, &fds) == 0) |
| && fdmatch(tcp, fds.fd)) |
| return 1; |
| |
| return 0; |
| } |
| |
| case SEN_bpf: |
| case SEN_epoll_create: |
| case SEN_epoll_create1: |
| case SEN_eventfd2: |
| case SEN_eventfd: |
| case SEN_fanotify_init: |
| case SEN_inotify_init1: |
| case SEN_memfd_create: |
| case SEN_perf_event_open: |
| case SEN_pipe: |
| case SEN_printargs: |
| case SEN_socket: |
| case SEN_socketpair: |
| case SEN_timerfd_create: |
| case SEN_timerfd_gettime: |
| case SEN_timerfd_settime: |
| /* |
| * These have TRACE_FILE or TRACE_DESCRIPTOR or TRACE_NETWORK set, |
| * but they don't have any file descriptor or path args to test. |
| */ |
| return 0; |
| } |
| |
| /* |
| * Our fallback position for calls that haven't already |
| * been handled is to just check arg[0]. |
| */ |
| |
| if (s->sys_flags & TRACE_FILE) |
| return upathmatch(tcp, tcp->u_arg[0]); |
| |
| if (s->sys_flags & (TRACE_DESC | TRACE_NETWORK)) |
| return fdmatch(tcp, tcp->u_arg[0]); |
| |
| return 0; |
| } |