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 A3A9E426ED8 for ; Fri, 5 Jun 2026 20:34:07 +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=1780691649; cv=none; b=b+LodUrQLK1em2b4y8xXRd31kjtvTJzwTjKXqSnhpzqlGavcM2hTa1N9IgFpcEEvTw/6BxQ8FsQL4bJSgShq7fo/gNMULqNpuu6D7fYmwXdVCTrfYFwRojdj5jEFBjRZ0LKiWddsCfV5OsgYHRR0lJxxJeV4p1cccW6pCeyqRH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780691649; c=relaxed/simple; bh=gzuRP/n7pxQ4GuENHZDal5QlH7HLDjaJOQ1+SE5ZIxQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uTeEJQuwroFGrwhlYpZVv2dcnfPwZU0mnvv4xw+i4eHuiQCFxWyzxaD8CuaW83VLCP+ttzj9SVdBlSUq1cxwW+HbshHmS2wjJcWC4XRZAMZ2XNWbR5r4wCXl1Juesgn+OcN3NsaWhngEDvex5k1V7aqEO10Gyuz/hEZxAE66vLA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JIDPIrhO; 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="JIDPIrhO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C27561F00893; Fri, 5 Jun 2026 20:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780691647; bh=kD+ncupLfJOvm5SjXhqrw8P4hlBUMTXzdfPZUhnKOzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JIDPIrhOl3qtX2SuWbMU9eS7jDl0YgAQOIK0Syb6JNE7AtQtv5IJr6r8a1TE70SH2 2L1qbNnrKZt/YYt9Ktm2P4lrDxxxMWDGzJlduLQFfBQepo09TAQYQ9BD2QfKXNNLlj wNwH7Mee7zzi754xRCoDd8J1YAzFrCxKksAOvB/vUgH8wxAiNRzt7Hnt0vfNhY5SjI ERVcqypW9SuVxU46ahaD3TyMLoeIIFg88pIULsHQwtAcV9AfVzcIIhNZH9VyuX/1Nq Z7aTk93yrRHCPFznAXDF15ZnLzAoNT/vClUNA+YckgC0p56Pkp/eY6N6mEnnRdIZkG KGnZ+Ronq9etQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Michael Bommarito , John Garry , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 5.15.y] scsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf Date: Fri, 5 Jun 2026 16:34:05 -0400 Message-ID: <20260605203405.2224281-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026060410-slam-conch-e2f1@gregkh> References: <2026060410-slam-conch-e2f1@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Michael Bommarito [ Upstream commit bf33e01f88388c43e285492a63e539df6ffed64c ] iscsi_encode_text_output() concatenates "key=value\0" records into login->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer allocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call sites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check the remaining buffer capacity: *length += sprintf(output_buf, "%s=%s", er->key, er->value); *length += 1; output_buf = textbuf + *length; The 8192-byte ceiling at iscsi_target_check_login_request() bounds the *input* Login PDU payload, but a single PDU can carry up to 2048 minimal four-byte "a=b\0" pairs, each unknown key expanding to a 16-byte "a=NotUnderstood\0" output record via iscsi_add_notunderstood_response(). 2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB heap overrun in the kmalloc-8k slab. The fix introduces a static iscsi_encode_text_record() helper that uses snprintf() with a per-call bounds check against the remaining buffer, and threads a u32 textbuf_size parameter through iscsi_encode_text_output(). Both call sites in iscsi_target_handle_csg_zero() (PHASE_SECURITY) and iscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass MAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls iscsi_release_extra_responses() to drop queued records, and returns -1; both caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR / ISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning, so the initiator sees an explicit failed-login response rather than a silent connection drop. (Prior to this patch only the PHASE_OPERATIONAL caller did that; the PHASE_SECURITY caller is converted to the same shape.) Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Tested-by: John Garry Reviewed-by: John Garry Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/iscsi/iscsi_target_nego.c | 7 ++- .../target/iscsi/iscsi_target_parameters.c | 62 ++++++++++++++----- .../target/iscsi/iscsi_target_parameters.h | 2 +- 3 files changed, 55 insertions(+), 16 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index 32a2852352db1c..2ff2cbdd2598f9 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -870,10 +870,14 @@ static int iscsi_target_handle_csg_zero( SENDER_TARGET, login->rsp_buf, &login->rsp_length, + MAX_KEY_VALUE_PAIRS, conn->param_list, conn->tpg->tpg_attrib.login_keys_workaround); - if (ret < 0) + if (ret < 0) { + iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_INITIATOR_ERR, + ISCSI_LOGIN_STATUS_INIT_ERR); return -1; + } if (!iscsi_check_negotiated_keys(conn->param_list)) { if (conn->tpg->tpg_attrib.authentication && @@ -941,6 +945,7 @@ static int iscsi_target_handle_csg_one(struct iscsi_conn *conn, struct iscsi_log SENDER_TARGET, login->rsp_buf, &login->rsp_length, + MAX_KEY_VALUE_PAIRS, conn->param_list, conn->tpg->tpg_attrib.login_keys_workaround); if (ret < 0) { diff --git a/drivers/target/iscsi/iscsi_target_parameters.c b/drivers/target/iscsi/iscsi_target_parameters.c index 62004e3fe1ccc3..74624c67d189d1 100644 --- a/drivers/target/iscsi/iscsi_target_parameters.c +++ b/drivers/target/iscsi/iscsi_target_parameters.c @@ -1419,19 +1419,42 @@ int iscsi_decode_text_input( return -1; } +/* + * Append "key=value" plus a trailing NUL into @textbuf at *@length. + * Returns 0 on success and advances *@length, or -EMSGSIZE if the + * record (including the NUL) would not fit in the remaining buffer. + */ +static int iscsi_encode_text_record(char *textbuf, u32 *length, + u32 textbuf_size, + const char *key, const char *value) +{ + int n; + u32 avail; + + if (*length >= textbuf_size) + return -EMSGSIZE; + + avail = textbuf_size - *length; + n = snprintf(textbuf + *length, avail, "%s=%s", key, value); + if (n < 0 || (u32)n + 1 > avail) + return -EMSGSIZE; + + *length += n + 1; + return 0; +} + int iscsi_encode_text_output( u8 phase, u8 sender, char *textbuf, u32 *length, + u32 textbuf_size, struct iscsi_param_list *param_list, bool keys_workaround) { - char *output_buf = NULL; struct iscsi_extra_response *er; struct iscsi_param *param; - - output_buf = textbuf + *length; + int ret; if (iscsi_enforce_integrity_rules(phase, param_list) < 0) return -1; @@ -1443,10 +1466,12 @@ int iscsi_encode_text_output( !IS_PSTATE_RESPONSE_SENT(param) && !IS_PSTATE_REPLY_OPTIONAL(param) && (param->phase & phase)) { - *length += sprintf(output_buf, "%s=%s", - param->name, param->value); - *length += 1; - output_buf = textbuf + *length; + ret = iscsi_encode_text_record(textbuf, length, + textbuf_size, + param->name, + param->value); + if (ret < 0) + goto err_overflow; SET_PSTATE_RESPONSE_SENT(param); pr_debug("Sending key: %s=%s\n", param->name, param->value); @@ -1456,10 +1481,12 @@ int iscsi_encode_text_output( !IS_PSTATE_ACCEPTOR(param) && !IS_PSTATE_PROPOSER(param) && (param->phase & phase)) { - *length += sprintf(output_buf, "%s=%s", - param->name, param->value); - *length += 1; - output_buf = textbuf + *length; + ret = iscsi_encode_text_record(textbuf, length, + textbuf_size, + param->name, + param->value); + if (ret < 0) + goto err_overflow; SET_PSTATE_PROPOSER(param); iscsi_check_proposer_for_optional_reply(param, keys_workaround); @@ -1469,14 +1496,21 @@ int iscsi_encode_text_output( } list_for_each_entry(er, ¶m_list->extra_response_list, er_list) { - *length += sprintf(output_buf, "%s=%s", er->key, er->value); - *length += 1; - output_buf = textbuf + *length; + ret = iscsi_encode_text_record(textbuf, length, textbuf_size, + er->key, er->value); + if (ret < 0) + goto err_overflow; pr_debug("Sending key: %s=%s\n", er->key, er->value); } iscsi_release_extra_responses(param_list); return 0; + +err_overflow: + pr_err("iSCSI login response buffer (%u bytes) exhausted, dropping login.\n", + textbuf_size); + iscsi_release_extra_responses(param_list); + return -1; } int iscsi_check_negotiated_keys(struct iscsi_param_list *param_list) diff --git a/drivers/target/iscsi/iscsi_target_parameters.h b/drivers/target/iscsi/iscsi_target_parameters.h index 240c4c4344f691..6d02d19eb8cf0f 100644 --- a/drivers/target/iscsi/iscsi_target_parameters.h +++ b/drivers/target/iscsi/iscsi_target_parameters.h @@ -46,7 +46,7 @@ extern struct iscsi_param *iscsi_find_param_from_key(char *, struct iscsi_param_ extern int iscsi_extract_key_value(char *, char **, char **); extern int iscsi_update_param_value(struct iscsi_param *, char *); extern int iscsi_decode_text_input(u8, u8, char *, u32, struct iscsi_conn *); -extern int iscsi_encode_text_output(u8, u8, char *, u32 *, +extern int iscsi_encode_text_output(u8, u8, char *, u32 *, u32, struct iscsi_param_list *, bool); extern int iscsi_check_negotiated_keys(struct iscsi_param_list *); extern void iscsi_set_connection_parameters(struct iscsi_conn_ops *, -- 2.53.0