diff options
Diffstat (limited to 'libminijailpreload.c')
| -rw-r--r-- | libminijailpreload.c | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/libminijailpreload.c b/libminijailpreload.c index a98b736..b5a3c75 100644 --- a/libminijailpreload.c +++ b/libminijailpreload.c @@ -11,6 +11,7 @@ #include "libminijail.h" #include "libminijail-private.h" +#include "util.h" #include <dlfcn.h> #include <stdio.h> @@ -23,18 +24,24 @@ static int (*real_main) (int, char **, char **); static void *libc_handle; -static void die(const char *failed) +static void truncate_preload_env(char **envp, const char *name) { - syslog(LOG_ERR, "libminijail: %s", failed); - abort(); -} - -static void unset_in_env(char **envp, const char *name) -{ - int i; - for (i = 0; envp[i]; i++) - if (!strncmp(envp[i], name, strlen(name))) - envp[i][0] = '\0'; + char *env_value = minijail_getenv(envp, name); + if (env_value) { + /* + * if we have more than just libminijailpreload.so in + * LD_PRELOAD, cut out libminijailpreload.so from it, + * as it is guaranteed to always be last in the + * LD_PRELOAD list. + */ + char *last_space = strrchr(env_value, ' '); + if (last_space) { + *last_space = '\0'; + } else { + /* Only our lib was in LD_PRELOAD, just unset it. */ + minijail_unsetenv(envp, name); + } + } } /** @brief Fake main(), spliced in before the real call to main() by @@ -71,12 +78,10 @@ static int fake_main(int argc, char **argv, char **envp) die("preload: failed to parse minijail from parent"); close(fd); - unset_in_env(envp, kFdEnvVar); - /* TODO(ellyjones): this trashes existing preloads, so one can't do: - * LD_PRELOAD="/tmp/test.so libminijailpreload.so" prog; the - * descendants of prog will have no LD_PRELOAD set at all. - */ - unset_in_env(envp, kLdPreloadEnvVar); + minijail_unsetenv(envp, kFdEnvVar); + + truncate_preload_env(envp, kLdPreloadEnvVar); + /* Strip out flags meant for the parent. */ minijail_preenter(j); minijail_enter(j); |