trace: check asprintf() return value

[project/procd.git] / trace / trace.c

diff --git a/trace/trace.c b/trace/trace.c
index e7b7610..27cf108 100644 (file)
--- a/trace/trace.c
+++ b/trace/trace.c
@@ -25,7 +25,7 @@
 #include <errno.h>
 #include <string.h>
 #include <syslog.h>
-#include <err.h>
+#include <limits.h>
 
 #ifndef PTRACE_EVENT_STOP
 /* PTRACE_EVENT_STOP is defined in linux/ptrace.h, but this header
@@ -33,6 +33,7 @@
 #define PTRACE_EVENT_STOP 128
 #endif
 
+#include <libubox/ulog.h>
 #include <libubox/uloop.h>
 #include <libubox/blobmsg.h>
 #include <libubox/blobmsg_json.h>
@@ -66,21 +67,6 @@ enum mode {
        SECCOMP_TRACE,
 } mode = UTRACE;
 
-#define PROC_NAME(mode) (mode == UTRACE ? "utrace" : "seccomp-trace")
-
-#define INFO(fmt, ...) do { \
-       fprintf(stderr, "%s: "fmt, PROC_NAME(mode), ## __VA_ARGS__); \
-} while (0)
-
-#define ERROR(fmt, ...) do { \
-       syslog(LOG_ERR, "%s: "fmt, PROC_NAME(mode), ## __VA_ARGS__); \
-       fprintf(stderr, "%s: "fmt, PROC_NAME(mode), ## __VA_ARGS__);  \
-} while (0)
-
-#define LOGERR(fmt, ...) do { \
-       syslog(LOG_ERR, "%s: "fmt, PROC_NAME(mode), ## __VA_ARGS__); \
-} while (0)
-
 struct tracee {
        struct uloop_process proc;
        int in_syscall;
@@ -152,7 +138,7 @@ static void print_syscalls(int policy, const char *json)
                                       sc, syscall_name(sc), sorted[i].count);
                        blobmsg_add_string(&b, NULL, syscall_name(sc));
                } else {
-                       ERROR("no name found for syscall(%d)\n", sc);
+                       ULOG_ERR("no name found for syscall(%d)\n", sc);
                }
        }
        blobmsg_close_array(&b, c);
@@ -162,9 +148,9 @@ static void print_syscalls(int policy, const char *json)
                if (fp) {
                        fprintf(fp, "%s", blobmsg_format_json_indent(b.head, true, 0));
                        fclose(fp);
-                       INFO("saving syscall trace to %s\n", json);
+                       ULOG_INFO("saving syscall trace to %s\n", json);
                } else {
-                       ERROR("failed to open %s\n", json);
+                       ULOG_ERR("failed to open %s\n", json);
                }
        } else {
                printf("%s\n",
@@ -190,11 +176,11 @@ static void report_seccomp_vialation(pid_t pid, unsigned syscall)
        int i = syscall_index(syscall);
        if (i >= 0) {
                syscall_count[i]++;
-               LOGERR("%s[%u] tried to call non-whitelisted syscall: %s (see %s)\n",
-                      buf, pid,  syscall_name(syscall), json);
+               ULOG_ERR("%s[%u] tried to call non-whitelisted syscall: %s (see %s)\n",
+                        buf, pid,  syscall_name(syscall), json);
        } else {
-               LOGERR("%s[%u] tried to call non-whitelisted syscall: %d (see %s)\n",
-                      buf, pid,  syscall, json);
+               ULOG_ERR("%s[%u] tried to call non-whitelisted syscall: %d (see %s)\n",
+                        buf, pid,  syscall, json);
        }
 }
 
@@ -331,17 +317,21 @@ int main(int argc, char **argv, char **envp)
                case SECCOMP_TRACE:
                        preload = "/lib/libpreload-seccomp.so";
                        newenv = 2;
-                       asprintf(&_envp[1], "SECCOMP_FILE=%s", json ? json : "");
+                       if (asprintf(&_envp[1], "SECCOMP_FILE=%s", json ? json : "") < 0)
+                               ULOG_ERR("failed to allocate SECCOMP_FILE env: %m\n");
+
                        kill(getpid(), SIGSTOP);
                        break;
                }
-               asprintf(&_envp[0], "LD_PRELOAD=%s%s%s", preload,
-                        old_preload ? ":" : "",
-                        old_preload ? old_preload : "");
+               if (asprintf(&_envp[0], "LD_PRELOAD=%s%s%s", preload,
+                            old_preload ? ":" : "",
+                             old_preload ? old_preload : "") < 0)
+                       ULOG_ERR("failed to allocate LD_PRELOAD env: %m\n");
+
                memcpy(&_envp[newenv], envp, envc * sizeof(char *));
 
                ret = execve(_argv[0], _argv, _envp);
-               ERROR("failed to exec %s: %s\n", _argv[0], strerror(errno));
+               ULOG_ERR("failed to exec %s: %m\n", _argv[0]);
 
                free(_argv);
                free(_envp);
@@ -353,10 +343,13 @@ int main(int argc, char **argv, char **envp)
 
        waitpid(child, &status, WUNTRACED);
        if (!WIFSTOPPED(status)) {
-               ERROR("failed to start %s\n", *argv);
+               ULOG_ERR("failed to start %s\n", *argv);
                return -1;
        }
 
+       /* Initialize uloop to catch all ptrace stops from now on. */
+       uloop_init();
+
        int ptrace_options = PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | PTRACE_O_TRACECLONE;
        switch (mode) {
        case UTRACE:
@@ -368,12 +361,15 @@ int main(int argc, char **argv, char **envp)
                ptrace_restart = PTRACE_CONT;
                break;
        }
-       if (ptrace(PTRACE_SEIZE, child, 0, ptrace_options) == -1)
-               err(1, "PTRACE_SEIZE");
-       if (ptrace(ptrace_restart, child, 0, SIGCONT) == -1)
-               err(1, "ptrace restart");
+       if (ptrace(PTRACE_SEIZE, child, 0, ptrace_options) == -1) {
+               ULOG_ERR("PTRACE_SEIZE: %m\n");
+               return -1;
+       }
+       if (ptrace(ptrace_restart, child, 0, SIGCONT) == -1) {
+               ULOG_ERR("ptrace_restart: %m\n");
+               return -1;
+       }
 
-       uloop_init();
        tracer.proc.pid = child;
        tracer.proc.cb = tracer_cb;
        uloop_process_add(&tracer.proc);
@@ -386,12 +382,13 @@ int main(int argc, char **argv, char **envp)
        case UTRACE:
                if (!json)
                        if (asprintf(&json, "/tmp/%s.%u.json", basename(*argv), child) < 0)
-                               ERROR("failed to allocate output path: %s\n", strerror(errno));
+                               ULOG_ERR("failed to allocate output path: %m\n");
                break;
        case SECCOMP_TRACE:
                if (!violation_count)
                        return 0;
-               asprintf(&json, "/tmp/%s.%u.violations.json", basename(*argv), child);
+               if (asprintf(&json, "/tmp/%s.%u.violations.json", basename(*argv), child) < 0)
+                       ULOG_ERR("failed to allocate violations output path: %m\n");
                break;
        }
        print_syscalls(policy, json);