From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by sourceware.org (Postfix) with ESMTPS id F3D563856974 for ; Fri, 21 Oct 2022 17:42:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org F3D563856974 Received: by mail-ed1-x530.google.com with SMTP id g27so8584734edf.11 for ; Fri, 21 Oct 2022 10:42:11 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=V2zRdGSmaYeIqPbCIt0h9Qco99f0gY02zNpwRGuY2qc=; b=buGs2IE69BORHhrcS81VP80Qsq7nxJTSHCFSw7iTMVTkQIgyonnoaGoRD2PScfz0cc Bg/tYmZsaN5JCncFByNHGKZZcDlfhuD4fHnkJWJoPeR8sr/Ru8X6u9nNdTtWA9JPCe1m eQp+aOesyQ5tDNcgSCniqzCG+nmBu3hWumtQSsJnIh5PwEVut5AKzPO2iYKbmJaX9W1W 8Qde+sUtoDV4cMzbP5tiYBSeDrhgZGwXru+WYuLBikkSYssH91GvNS1tczXIn7C3Nq5E Np79lcrBmzkKhgqQ9+eK13H/XpAk1UP+QZbexFWvff+5nbR616MzWuOtjSUkAeTRYsZc uPVg== X-Gm-Message-State: ACrzQf29UnDLYsQCWPEa2QFCDgDkzf17nUsBRRUDtBqLctUD/yY8cvSd J7XjW8OPDdTiuNICJ2RBs81egGpI3zaAyg== X-Google-Smtp-Source: AMsMyM556Z5IRhoXCGBgvDo+Wg/52fHHFmT623h0nYqtH5SBsdGDQODxHWvzv7+r489KC5c4+44lMg== X-Received: by 2002:a50:ff09:0:b0:456:fd61:83b3 with SMTP id a9-20020a50ff09000000b00456fd6183b3mr18055083edu.166.1666374129654; Fri, 21 Oct 2022 10:42:09 -0700 (PDT) Received: from codespaces-99e6ae.cwehd3ikdxye1e5jw03kh0ngkf.ax.internal.cloudapp.net ([104.40.192.11]) by smtp.gmail.com with ESMTPSA id 1-20020a170906200100b007933047f930sm3593150ejo.157.2022.10.21.10.42.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Oct 2022 10:42:09 -0700 (PDT) From: Asaf Fisher To: gdb-patches@sourceware.org Cc: Asaf Fisher Subject: [PATCH v3 2/2] Make GDB resolve dlopen of memory mapped shared libraries Date: Fri, 21 Oct 2022 17:42:05 +0000 Message-Id: <20221021174205.5389-2-asaffisher.dev@gmail.com> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221021174205.5389-1-asaffisher.dev@gmail.com> References: <20221021174205.5389-1-asaffisher.dev@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Oct 2022 17:42:15 -0000 Introduced `check_proc_self_file` that checks if a path used by inferior in dlopen is in the form of `/proc/self/...` and if so resolves it to `/proc/[pid]/...` Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29586 --- gdb/solib-svr4.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 57 insertions(+), 2 deletions(-) diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 6acaf87960b..02bd89ef9d6 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -34,6 +34,7 @@ #include "regcache.h" #include "gdbthread.h" #include "observable.h" +#include "gdbsupport/pathstuff.h" #include "solist.h" #include "solib.h" @@ -48,6 +49,9 @@ #include +#define SLASH_SELF "/self" +#define PROC_SELF "/proc" SLASH_SELF + static struct link_map_offsets *svr4_fetch_link_map_offsets (void); static int svr4_have_link_map_offsets (void); static void svr4_relocate_main_executable (void); @@ -1259,6 +1263,55 @@ svr4_default_sos (svr4_info *info) return newobj; } +/* Check and fix a cenerio where the so path that we extract has a path to + /proc/self e.g. /proc/self/fd/[fd_num] If inferior dlopen a path that has + /proc/self, GDB must not open it directly becuase the files in /proc/self are + unique for each process. Instead we resolve /proc/self to + /proc/[inferior_pid]. This change will give GDB the correct path */ + +static size_t +check_proc_self_file(char *so_name, char *normalized_so_name, + size_t out_normalized_so_name_len) { + /* We dont want a path with /../ yak. */ + gdb::unique_xmalloc_ptr normalized_path_obj = gdb_realpath(so_name); + gdb::string_view normalized_path = gdb::string_view( + normalized_path_obj.get(), + std::min(strlen(normalized_path_obj.get()), out_normalized_so_name_len)); + + /* Is the path really a /proc/self? */ + if (0 != normalized_path.rfind(PROC_SELF, 0)) return 0; + + /* Lets get the part of the path after /proc/self e.g. /proc/self/fd -> /fd */ + size_t slash_self_index = normalized_path.rfind(SLASH_SELF); + if (std::string::npos == slash_self_index) return 0; + size_t after_self_index = slash_self_index + strlen(SLASH_SELF); + gdb::string_view after_self_path = normalized_path.substr(after_self_index); + + /* Get inferior path */ + int inferior_pid = inferior_ptid.pid(); + std::string inferior_procfs_path = string_printf("/proc/%d", inferior_pid); + + /* Check if there's enoght space in the out buffer for the normalized path. */ + size_t normalized_so_name_length = + inferior_procfs_path.length() + after_self_path.length(); + if (out_normalized_so_name_len < normalized_so_name_length) return 0; + + /* Build the full path */ + inferior_procfs_path.append(std::string(after_self_path)); + + warning(_("Detected loaded library (%s) from /proc/self.\nAttempting to " + "replace `self` with inferior's PID. -> %s"), + normalized_path.begin(), inferior_procfs_path.c_str()); + + auto out_length = + std::min(inferior_procfs_path.length(), out_normalized_so_name_len); + + /* Copy the new path to the out buffer */ + strncpy(normalized_so_name, inferior_procfs_path.c_str(), out_length); + + return out_length; +} + /* Read the whole inferior libraries chain starting at address LM. Expect the first entry in the chain's previous entry to be PREV_LM. Add the entries to the tail referenced by LINK_PTR_PTR. Ignore the @@ -1318,8 +1371,10 @@ svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm, warning (_("Can't read pathname for load map.")); continue; } - - strncpy (newobj->so_name, buffer.get (), SO_NAME_MAX_PATH_SIZE - 1); + /* Check if path is in /proc/self */ + if (0 == check_proc_self_file(buffer.get(), newobj->so_name, + SO_NAME_MAX_PATH_SIZE - 1)) + strncpy(newobj->so_name, buffer.get(), SO_NAME_MAX_PATH_SIZE - 1); newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; strcpy (newobj->so_original_name, newobj->so_name); -- 2.38.0