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author | Elliott Hughes <enh@google.com> | 2019-03-13 11:15:06 -0700 |
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committer | Elliott Hughes <enh@google.com> | 2019-03-13 11:16:03 -0700 |
commit | 964932d7ce1f84025bb7d92e6dbc8932cbb8e200 (patch) | |
tree | 2e96999aaf6c08f8617b1e5454c0692e9a28c489 /run-as | |
parent | 6c5c085e4190c70474ad85b711ffb7b0b682babf (diff) | |
download | core-964932d7ce1f84025bb7d92e6dbc8932cbb8e200.tar.gz |
run-as: improve diagnostics on failure.
Bug: http://b/128523258
Test: manual
Change-Id: I4430a8d309c0e9b5315aaae3e7d223c05b7ea3e5
Diffstat (limited to 'run-as')
-rw-r--r-- | run-as/run-as.cpp | 42 |
1 files changed, 25 insertions, 17 deletions
diff --git a/run-as/run-as.cpp b/run-as/run-as.cpp index 8752eef4c..432c434b4 100644 --- a/run-as/run-as.cpp +++ b/run-as/run-as.cpp @@ -70,32 +70,40 @@ static bool packagelist_parse_callback(pkg_info* this_package, void* userdata) { return true; // Keep searching. } -static bool check_directory(const char* path, uid_t uid) { +static void check_directory(const char* path, uid_t uid) { struct stat st; - if (TEMP_FAILURE_RETRY(lstat(path, &st)) == -1) return false; + if (TEMP_FAILURE_RETRY(lstat(path, &st)) == -1) { + error(1, errno, "couldn't stat %s", path); + } // /data/user/0 is a known safe symlink. - if (strcmp("/data/user/0", path) == 0) return true; + if (strcmp("/data/user/0", path) == 0) return; // Must be a real directory, not a symlink. - if (!S_ISDIR(st.st_mode)) return false; + if (!S_ISDIR(st.st_mode)) { + error(1, 0, "%s not a directory: %o", path, st.st_mode); + } // Must be owned by specific uid/gid. - if (st.st_uid != uid || st.st_gid != uid) return false; + if (st.st_uid != uid || st.st_gid != uid) { + error(1, 0, "%s has wrong owner: %d/%d, not %d", path, st.st_uid, st.st_gid, uid); + } // Must not be readable or writable by others. - if ((st.st_mode & (S_IROTH|S_IWOTH)) != 0) return false; - - return true; + if ((st.st_mode & (S_IROTH | S_IWOTH)) != 0) { + error(1, 0, "%s readable or writable by others: %o", path, st.st_mode); + } } // This function is used to check the data directory path for safety. // We check that every sub-directory is owned by the 'system' user // and exists and is not a symlink. We also check that the full directory // path is properly owned by the user ID. -static bool check_data_path(const char* data_path, uid_t uid) { +static void check_data_path(const char* package_name, const char* data_path, uid_t uid) { // The path should be absolute. - if (data_path[0] != '/') return false; + if (data_path[0] != '/') { + error(1, 0, "%s data path not absolute: %s", package_name, data_path); + } // Look for all sub-paths, we do that by finding // directory separators in the input path and @@ -110,26 +118,28 @@ static bool check_data_path(const char* data_path, uid_t uid) { if (data_path[nn+1] == '\0') break; /* found a separator, check that data_path is not too long. */ - if (nn >= (int)(sizeof subpath)) return false; + if (nn >= (int)(sizeof subpath)) { + error(1, 0, "%s data path too long: %s", package_name, data_path); + } /* reject any '..' subpath */ if (nn >= 3 && data_path[nn-3] == '/' && data_path[nn-2] == '.' && data_path[nn-1] == '.') { - return false; + error(1, 0, "%s contains '..': %s", package_name, data_path); } /* copy to 'subpath', then check ownership */ memcpy(subpath, data_path, nn); subpath[nn] = '\0'; - if (!check_directory(subpath, AID_SYSTEM)) return false; + check_directory(subpath, AID_SYSTEM); } // All sub-paths were checked, now verify that the full data // directory is owned by the application uid. - return check_directory(data_path, uid); + check_directory(data_path, uid); } std::vector<gid_t> get_supplementary_gids(uid_t userAppId) { @@ -222,9 +232,7 @@ int main(int argc, char* argv[]) { } // Check that the data directory path is valid. - if (!check_data_path(info.data_dir, userAppId)) { - error(1, 0, "package has corrupt installation: %s", pkgname); - } + check_data_path(pkgname, info.data_dir, userAppId); // Ensure that we change all real/effective/saved IDs at the // same time to avoid nasty surprises. |