Merge pull request #9018 from poettering/get-process-comm-is-print
some extra safety checks for get_process_comm()
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
@@ -18,6 +18,8 @@
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int cescape_char(char c, char *buf) {
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char *buf_old = buf;
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/* Needs space for 4 characters in the buffer */
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switch (c) {
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case '\a':
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@@ -1407,4 +1407,11 @@ struct statx {
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#define AT_STATX_DONT_SYNC 0x4000
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#endif
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/* The maximum thread/process name length including trailing NUL byte. This mimics the kernel definition of the same
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* name, which we need in userspace at various places but is not defined in userspace currently, neither under this
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* name nor any other. */
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#ifndef TASK_COMM_LEN
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#define TASK_COMM_LEN 16
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#endif
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#include "missing_syscall.h"
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+25
-11
@@ -76,20 +76,31 @@ int get_process_state(pid_t pid) {
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return (unsigned char) state;
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}
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int get_process_comm(pid_t pid, char **name) {
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int get_process_comm(pid_t pid, char **ret) {
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_cleanup_free_ char *escaped = NULL, *comm = NULL;
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const char *p;
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int r;
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assert(name);
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assert(ret);
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assert(pid >= 0);
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escaped = new(char, TASK_COMM_LEN);
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if (!escaped)
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return -ENOMEM;
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p = procfs_file_alloca(pid, "comm");
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r = read_one_line_file(p, name);
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r = read_one_line_file(p, &comm);
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if (r == -ENOENT)
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return -ESRCH;
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if (r < 0)
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return r;
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return r;
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/* Escape unprintable characters, just in case, but don't grow the string beyond the underlying size */
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cellescape(escaped, TASK_COMM_LEN, comm);
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*ret = TAKE_PTR(escaped);
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return 0;
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}
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int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line) {
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@@ -296,7 +307,7 @@ int rename_process(const char name[]) {
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* can use PR_SET_NAME, which sets the thread name for the calling thread. */
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if (prctl(PR_SET_NAME, name) < 0)
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log_debug_errno(errno, "PR_SET_NAME failed: %m");
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if (l > 15) /* Linux process names can be 15 chars at max */
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if (l >= TASK_COMM_LEN) /* Linux process names can be 15 chars at max */
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truncated = true;
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/* Second step, change glibc's ID of the process name. */
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@@ -740,14 +751,17 @@ int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags) {
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/*
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* Return values:
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* < 0 : wait_for_terminate_with_timeout() failed to get the state of the
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* process, the process timed out, the process was terminated by a
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* signal, or failed for an unknown reason.
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*
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* < 0 : wait_for_terminate_with_timeout() failed to get the state of the process, the process timed out, the process
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* was terminated by a signal, or failed for an unknown reason.
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*
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* >=0 : The process terminated normally with no failures.
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*
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* Success is indicated by a return value of zero, a timeout is indicated
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* by ETIMEDOUT, and all other child failure states are indicated by error
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* is indicated by a non-zero value.
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* Success is indicated by a return value of zero, a timeout is indicated by ETIMEDOUT, and all other child failure
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* states are indicated by error is indicated by a non-zero value.
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*
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* This call assumes SIGCHLD has been blocked already, in particular before the child to wait for has been forked off
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* to remain entirely race-free.
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*/
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int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout) {
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sigset_t mask;
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+45
-12
@@ -627,25 +627,58 @@ char *cellescape(char *buf, size_t len, const char *s) {
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* very end.
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*/
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size_t i;
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const char *t = s;
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size_t i = 0, last_char_width[4] = {}, k = 0, j;
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assert(len > 4 + 4 + 1); /* two chars and the terminator */
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assert(len > 0); /* at least a terminating NUL */
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for (i = 0; i < len - 9; t++) {
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if (!*t)
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for (;;) {
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char four[4];
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int w;
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if (*s == 0) /* terminating NUL detected? then we are done! */
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goto done;
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i += cescape_char(*t, buf + i);
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w = cescape_char(*s, four);
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if (i + w + 1 > len) /* This character doesn't fit into the buffer anymore? In that case let's
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* ellipsize at the previous location */
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break;
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/* OK, there was space, let's add this escaped character to the buffer */
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memcpy(buf + i, four, w);
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i += w;
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/* And remember its width in the ring buffer */
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last_char_width[k] = w;
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k = (k + 1) % 4;
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s++;
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}
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/* We have space for one more char and terminating nul at this point */
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if (*t) {
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if (*(t+1))
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i += write_ellipsis(buf + i, false);
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else
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i += cescape_char(*t, buf + i);
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/* Ellipsation is necessary. This means we might need to truncate the string again to make space for 4
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* characters ideally, but the buffer is shorter than that in the first place take what we can get */
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for (j = 0; j < ELEMENTSOF(last_char_width); j++) {
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if (i + 4 <= len) /* nice, we reached our space goal */
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break;
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k = k == 0 ? 3 : k - 1;
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if (last_char_width[k] == 0) /* bummer, we reached the beginning of the strings */
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break;
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assert(i >= last_char_width[k]);
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i -= last_char_width[k];
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}
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if (i + 4 <= len) /* yay, enough space */
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i += write_ellipsis(buf + i, false);
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else if (i + 3 <= len) { /* only space for ".." */
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buf[i++] = '.';
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buf[i++] = '.';
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} else if (i + 2 <= len) /* only space for a single "." */
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buf[i++] = '.';
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else
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assert(i + 1 <= len);
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done:
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buf[i] = '\0';
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return buf;
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@@ -91,6 +91,38 @@ static void test_get_process_comm(pid_t pid) {
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log_info("PID"PID_FMT" $PATH: '%s'", pid, strna(i));
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}
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static void test_get_process_comm_escape_one(const char *input, const char *output) {
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_cleanup_free_ char *n = NULL;
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log_info("input: <%s> — output: <%s>", input, output);
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assert_se(prctl(PR_SET_NAME, input) >= 0);
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assert_se(get_process_comm(0, &n) >= 0);
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log_info("got: <%s>", n);
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assert_se(streq_ptr(n, output));
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}
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static void test_get_process_comm_escape(void) {
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_cleanup_free_ char *saved = NULL;
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assert_se(get_process_comm(0, &saved) >= 0);
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test_get_process_comm_escape_one("", "");
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test_get_process_comm_escape_one("foo", "foo");
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test_get_process_comm_escape_one("012345678901234", "012345678901234");
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test_get_process_comm_escape_one("0123456789012345", "012345678901234");
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test_get_process_comm_escape_one("äöüß", "\\303\\244\\303…");
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test_get_process_comm_escape_one("xäöüß", "x\\303\\244…");
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test_get_process_comm_escape_one("xxäöüß", "xx\\303\\244…");
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test_get_process_comm_escape_one("xxxäöüß", "xxx\\303\\244…");
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test_get_process_comm_escape_one("xxxxäöüß", "xxxx\\303\\244…");
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test_get_process_comm_escape_one("xxxxxäöüß", "xxxxx\\303…");
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assert_se(prctl(PR_SET_NAME, saved) >= 0);
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}
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static void test_pid_is_unwaited(void) {
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pid_t pid;
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@@ -366,7 +398,7 @@ static void test_rename_process_now(const char *p, int ret) {
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assert_se(get_process_comm(0, &comm) >= 0);
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log_info("comm = <%s>", comm);
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assert_se(strneq(comm, p, 15));
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assert_se(strneq(comm, p, TASK_COMM_LEN-1));
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assert_se(get_process_cmdline(0, 0, false, &cmdline) >= 0);
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/* we cannot expect cmdline to be renamed properly without privileges */
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@@ -572,6 +604,7 @@ int main(int argc, char *argv[]) {
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test_get_process_comm(getpid());
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}
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test_get_process_comm_escape();
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test_pid_is_unwaited();
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test_pid_is_alive();
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test_personality();
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@@ -81,21 +81,79 @@ static void test_ascii_strcasecmp_nn(void) {
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static void test_cellescape(void) {
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char buf[40];
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assert_se(streq(cellescape(buf, 10, "1"), "1"));
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assert_se(streq(cellescape(buf, 10, "12"), "12"));
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assert_se(streq(cellescape(buf, 10, "123"), is_locale_utf8() ? "1…" : "1..."));
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assert_se(streq(cellescape(buf, 1, ""), ""));
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assert_se(streq(cellescape(buf, 1, "1"), ""));
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assert_se(streq(cellescape(buf, 1, "12"), ""));
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assert_se(streq(cellescape(buf, 10, "1\011"), "1\\t"));
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assert_se(streq(cellescape(buf, 10, "1\020"), "1\\020"));
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assert_se(streq(cellescape(buf, 10, "1\020x"), is_locale_utf8() ? "1…" : "1..."));
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assert_se(streq(cellescape(buf, 2, ""), ""));
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assert_se(streq(cellescape(buf, 2, "1"), "1"));
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assert_se(streq(cellescape(buf, 2, "12"), "."));
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assert_se(streq(cellescape(buf, 2, "123"), "."));
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assert_se(streq(cellescape(buf, 3, ""), ""));
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assert_se(streq(cellescape(buf, 3, "1"), "1"));
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assert_se(streq(cellescape(buf, 3, "12"), "12"));
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assert_se(streq(cellescape(buf, 3, "123"), ".."));
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assert_se(streq(cellescape(buf, 3, "1234"), ".."));
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assert_se(streq(cellescape(buf, 4, ""), ""));
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assert_se(streq(cellescape(buf, 4, "1"), "1"));
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assert_se(streq(cellescape(buf, 4, "12"), "12"));
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assert_se(streq(cellescape(buf, 4, "123"), "123"));
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assert_se(streq(cellescape(buf, 4, "1234"), is_locale_utf8() ? "…" : "..."));
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assert_se(streq(cellescape(buf, 4, "12345"), is_locale_utf8() ? "…" : "..."));
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assert_se(streq(cellescape(buf, 5, ""), ""));
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assert_se(streq(cellescape(buf, 5, "1"), "1"));
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assert_se(streq(cellescape(buf, 5, "12"), "12"));
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assert_se(streq(cellescape(buf, 5, "123"), "123"));
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assert_se(streq(cellescape(buf, 5, "1234"), "1234"));
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assert_se(streq(cellescape(buf, 5, "12345"), is_locale_utf8() ? "1…" : "1..."));
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assert_se(streq(cellescape(buf, 5, "123456"), is_locale_utf8() ? "1…" : "1..."));
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assert_se(streq(cellescape(buf, 1, "\020"), ""));
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assert_se(streq(cellescape(buf, 2, "\020"), "."));
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assert_se(streq(cellescape(buf, 3, "\020"), ".."));
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assert_se(streq(cellescape(buf, 4, "\020"), "…"));
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assert_se(streq(cellescape(buf, 5, "\020"), "\\020"));
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assert_se(streq(cellescape(buf, 5, "1234\020"), "1…"));
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assert_se(streq(cellescape(buf, 6, "1234\020"), "12…"));
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assert_se(streq(cellescape(buf, 7, "1234\020"), "123…"));
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assert_se(streq(cellescape(buf, 8, "1234\020"), "1234…"));
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assert_se(streq(cellescape(buf, 9, "1234\020"), "1234\\020"));
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assert_se(streq(cellescape(buf, 1, "\t\n"), ""));
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assert_se(streq(cellescape(buf, 2, "\t\n"), "."));
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assert_se(streq(cellescape(buf, 3, "\t\n"), ".."));
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assert_se(streq(cellescape(buf, 4, "\t\n"), "…"));
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assert_se(streq(cellescape(buf, 5, "\t\n"), "\\t\\n"));
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assert_se(streq(cellescape(buf, 5, "1234\t\n"), "1…"));
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assert_se(streq(cellescape(buf, 6, "1234\t\n"), "12…"));
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assert_se(streq(cellescape(buf, 7, "1234\t\n"), "123…"));
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assert_se(streq(cellescape(buf, 8, "1234\t\n"), "1234…"));
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assert_se(streq(cellescape(buf, 9, "1234\t\n"), "1234\\t\\n"));
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assert_se(streq(cellescape(buf, 4, "x\t\020\n"), "…"));
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assert_se(streq(cellescape(buf, 5, "x\t\020\n"), "x…"));
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assert_se(streq(cellescape(buf, 6, "x\t\020\n"), "x…"));
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assert_se(streq(cellescape(buf, 7, "x\t\020\n"), "x\\t…"));
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assert_se(streq(cellescape(buf, 8, "x\t\020\n"), "x\\t…"));
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assert_se(streq(cellescape(buf, 9, "x\t\020\n"), "x\\t…"));
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assert_se(streq(cellescape(buf, 10, "x\t\020\n"), "x\\t\\020\\n"));
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assert_se(streq(cellescape(buf, 6, "1\011"), "1\\t"));
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assert_se(streq(cellescape(buf, 6, "1\020"), "1\\020"));
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assert_se(streq(cellescape(buf, 6, "1\020x"), is_locale_utf8() ? "1…" : "1..."));
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assert_se(streq(cellescape(buf, 40, "1\020"), "1\\020"));
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assert_se(streq(cellescape(buf, 40, "1\020x"), "1\\020x"));
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assert_se(streq(cellescape(buf, 40, "\a\b\f\n\r\t\v\\\"'"), "\\a\\b\\f\\n\\r\\t\\v\\\\\\\"\\'"));
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assert_se(streq(cellescape(buf, 10, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a…" : "\\a..."));
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assert_se(streq(cellescape(buf, 11, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a…" : "\\a..."));
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assert_se(streq(cellescape(buf, 12, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a\\b…" : "\\a\\b..."));
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assert_se(streq(cellescape(buf, 6, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a…" : "\\a..."));
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assert_se(streq(cellescape(buf, 7, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a…" : "\\a..."));
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assert_se(streq(cellescape(buf, 8, "\a\b\f\n\r\t\v\\\"'"), is_locale_utf8() ? "\\a\\b…" : "\\a\\b..."));
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assert_se(streq(cellescape(buf, sizeof buf, "1\020"), "1\\020"));
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assert_se(streq(cellescape(buf, sizeof buf, "1\020x"), "1\\020x"));
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