From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3A943D9029; Mon, 20 Jul 2026 09:34:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784540059; cv=none; b=MMWsqXAyP1GMI3xMfeB7eLiRMtXhuQ3ZN9XfTY/1x1hxKCwHfD/9+DIpMuy362b2RNNBMKS0XA+br6B1+jaS8zDFWbrmHu9I/yodhsw57bNfHXbjYCAPotl2Ha22EAIizTPOUunvDG9c0dsbZGnbYsoFXgjWrYMA+3xGDAToSwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784540059; c=relaxed/simple; bh=S1I+8XOcJimoOZpkS+sQ4beHcupitoNVrqmvMwX3N3g=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tc+Tw2saoGuxodsCMX3wv0XUSrV8l1zBCdJIlUxr6p74XMEtayzh8mgHDmDAMWoAMdjVCIu+YXMeGLNnCbSyVHCwVvwebrR+IeameV1sa0p0EYwxMhae9Ymd55OoAjBftHo+IqaLO31DhfHSujaUXc1gI6l9aXg7qJ7P+bPPobU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XrEyjAsV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XrEyjAsV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 964FD1F000E9; Mon, 20 Jul 2026 09:34:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784540058; bh=2Vi2Y6eFLaZZncWxhzA85l4SRnVsg67aEdWUPdvtHPg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=XrEyjAsVS7VocJDQ+FLPK0E0rZI39Dwdh6rT79D3/z1ln1ia/tdKr77fL4myrxBLK QCQWUROnM69/sB3uDoCeGiQBeNiwcdluPoZxRIXSWGiR+0GOAZDFFmyUgf/FYyV3gf HvD5TqOH1bEg3Qa8MwMJAKZhS/4iodK/atJcoHnSbIkA/FHqudeoJ3//DpMSC0XnHr TBogyuFZsbFyB6yg211N9J1s6M1ZF30GQN69+dAoMEkSNKBkA5rRIMJaYX+0P0+fJY Dol6pOpfcns7rO1KOv7uiHGBe5kUL/8ve9TMFRXRVSaFodFHkbn6V6QbsppKnvs5ZU K6NXSdswly/Dg== From: Christian Brauner Date: Mon, 20 Jul 2026 11:33:29 +0200 Subject: [PATCH 06/21] binfmt_misc: split out build_interp_argv() Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260720-work-bpf-binfmt_misc-ptinterp-v1-6-ddb76c9a508e@kernel.org> References: <20260720-work-bpf-binfmt_misc-ptinterp-v1-0-ddb76c9a508e@kernel.org> In-Reply-To: <20260720-work-bpf-binfmt_misc-ptinterp-v1-0-ddb76c9a508e@kernel.org> To: Farid Zakaria , linux-fsdevel@vger.kernel.org Cc: Daniel Borkmann , Alexei Starovoitov , Kees Cook , Alexander Viro , Jan Kara , Jonathan Corbet , linux-mm@kvack.org, bpf@vger.kernel.org, jannh@google.com, mail@johnericson.me, "Christian Brauner (Amutable)" X-Mailer: b4 0.16-dev-4217c X-Developer-Signature: v=1; a=openpgp-sha256; l=3720; i=brauner@kernel.org; h=from:subject:message-id; bh=S1I+8XOcJimoOZpkS+sQ4beHcupitoNVrqmvMwX3N3g=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWTFvm7SDFilVPxMX2L7s6q2imjtE3NOdu7jMjk6dyIXq 36+qqxVRykLgxgXg6yYIotDu0m43HKeis1GmRowc1iZQIYwcHEKwEQaahn+uweJ89yx/B2WenzB +6tnN3+33VscXOLQM3npGlbhHO+pDQz/E7p5tp5b1nuP8fumJ4t9Sh9/1bkc6+mx/1vc0qXxK85 nsAAA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Building the interpreter's argument vector is the bulk of load_misc_binary() and the one part of it that is specific to the classic dispatch. Move it into its own helper so what remains reads as what it is: pick a handler, pick an interpreter, build the invocation, open it. No functional change. Signed-off-by: Christian Brauner (Amutable) --- fs/binfmt_misc.c | 84 ++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 54 insertions(+), 30 deletions(-) diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c index 63c10066e3a6..f0ccc5d000f6 100644 --- a/fs/binfmt_misc.c +++ b/fs/binfmt_misc.c @@ -382,40 +382,23 @@ static struct file *entry_open_interpreter(const struct binfmt_misc_entry *e, return no_free_ptr(interp_file); } -/* - * the loader itself +/** + * build_interp_argv - splice the interpreter invocation into the argv + * @bprm: binary that is being executed + * @interpreter: the interpreter selected for this exec + * @flags: invocation flags in effect for this exec + * + * The interpreter becomes argv[0] and the binary its last argument, with an + * optional staged argument in between. The caller's argv[0] is dropped + * unless 'P' keeps it. + * + * Return: 0 on success, a negative error code on failure */ -static int load_misc_binary(struct linux_binprm *bprm) +static int build_interp_argv(struct linux_binprm *bprm, const char *interpreter, + unsigned long flags) { - struct binfmt_misc_entry *fmt __free(put_binfmt_handler) = NULL; - const char *interpreter; - struct file *interp_file; - struct binfmt_misc *misc; - unsigned long flags; int retval; - misc = current_binfmt_misc(); - if (!READ_ONCE(misc->enabled)) - return -ENOEXEC; - - fmt = get_binfmt_handler(misc, bprm); - if (!fmt) - return -ENOEXEC; - - /* Need to be able to load the file after exec */ - if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) - return -ENOENT; - - interpreter = entry_select_interpreter(fmt, bprm); - if (IS_ERR(interpreter)) - return PTR_ERR(interpreter); - - flags = entry_invocation_flags(fmt, bprm); - if (flags & MISC_FMT_CREDENTIALS) - bprm->execfd_creds = 1; - if (flags & MISC_FMT_OPEN_BINARY) - bprm->have_execfd = 1; - /* The entry's own choice - not one accumulated from an earlier level. */ if (flags & MISC_FMT_PRESERVE_ARGV0) { bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0; @@ -451,6 +434,47 @@ static int load_misc_binary(struct linux_binprm *bprm) return retval; bprm->argc++; + return 0; +} + +/* + * the loader itself + */ +static int load_misc_binary(struct linux_binprm *bprm) +{ + struct binfmt_misc_entry *fmt __free(put_binfmt_handler) = NULL; + const char *interpreter; + struct file *interp_file; + struct binfmt_misc *misc; + unsigned long flags; + int retval; + + misc = current_binfmt_misc(); + if (!READ_ONCE(misc->enabled)) + return -ENOEXEC; + + fmt = get_binfmt_handler(misc, bprm); + if (!fmt) + return -ENOEXEC; + + /* Need to be able to load the file after exec */ + if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) + return -ENOENT; + + interpreter = entry_select_interpreter(fmt, bprm); + if (IS_ERR(interpreter)) + return PTR_ERR(interpreter); + + flags = entry_invocation_flags(fmt, bprm); + if (flags & MISC_FMT_CREDENTIALS) + bprm->execfd_creds = 1; + if (flags & MISC_FMT_OPEN_BINARY) + bprm->have_execfd = 1; + + retval = build_interp_argv(bprm, interpreter, flags); + if (retval) + return retval; + /* Update interp in case binfmt_script needs it. */ retval = bprm_change_interp(interpreter, bprm); if (retval < 0) -- 2.53.0