The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 689640efc0a2c4e07e6f88affe6d42cd40cc3f85 Mon Sep 17 00:00:00 2001 From: Sudeep Holla sudeep.holla@arm.com Date: Fri, 1 Jul 2022 17:03:10 +0100 Subject: [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
When scpi probe fails, at any point, we need to ensure that the scpi_info is not set and will remain NULL until the probe succeeds. If it is not taken care, then it could result use-after-free as the value is exported via get_scpi_ops() and could refer to a memory allocated via devm_kzalloc() but freed when the probe fails.
Link: https://lore.kernel.org/r/20220701160310.148344-1-sudeep.holla@arm.com Cc: stable@vger.kernel.org # 4.19+ Reported-by: huhai huhai@kylinos.cn Reviewed-by: Jackie Liu liuyun01@kylinos.cn Signed-off-by: Sudeep Holla sudeep.holla@arm.com
diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c index ddf0b9ff9e15..435d0e2658a4 100644 --- a/drivers/firmware/arm_scpi.c +++ b/drivers/firmware/arm_scpi.c @@ -815,7 +815,7 @@ static int scpi_init_versions(struct scpi_drvinfo *info) info->firmware_version = le32_to_cpu(caps.platform_version); } /* Ignore error if not implemented */ - if (scpi_info->is_legacy && ret == -EOPNOTSUPP) + if (info->is_legacy && ret == -EOPNOTSUPP) return 0;
return ret; @@ -913,13 +913,14 @@ static int scpi_probe(struct platform_device *pdev) struct resource res; struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; + struct scpi_drvinfo *scpi_drvinfo;
- scpi_info = devm_kzalloc(dev, sizeof(*scpi_info), GFP_KERNEL); - if (!scpi_info) + scpi_drvinfo = devm_kzalloc(dev, sizeof(*scpi_drvinfo), GFP_KERNEL); + if (!scpi_drvinfo) return -ENOMEM;
if (of_match_device(legacy_scpi_of_match, &pdev->dev)) - scpi_info->is_legacy = true; + scpi_drvinfo->is_legacy = true;
count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells"); if (count < 0) { @@ -927,19 +928,19 @@ static int scpi_probe(struct platform_device *pdev) return -ENODEV; }
- scpi_info->channels = devm_kcalloc(dev, count, sizeof(struct scpi_chan), - GFP_KERNEL); - if (!scpi_info->channels) + scpi_drvinfo->channels = + devm_kcalloc(dev, count, sizeof(struct scpi_chan), GFP_KERNEL); + if (!scpi_drvinfo->channels) return -ENOMEM;
- ret = devm_add_action(dev, scpi_free_channels, scpi_info); + ret = devm_add_action(dev, scpi_free_channels, scpi_drvinfo); if (ret) return ret;
- for (; scpi_info->num_chans < count; scpi_info->num_chans++) { + for (; scpi_drvinfo->num_chans < count; scpi_drvinfo->num_chans++) { resource_size_t size; - int idx = scpi_info->num_chans; - struct scpi_chan *pchan = scpi_info->channels + idx; + int idx = scpi_drvinfo->num_chans; + struct scpi_chan *pchan = scpi_drvinfo->channels + idx; struct mbox_client *cl = &pchan->cl; struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
@@ -986,45 +987,53 @@ static int scpi_probe(struct platform_device *pdev) return ret; }
- scpi_info->commands = scpi_std_commands; + scpi_drvinfo->commands = scpi_std_commands;
- platform_set_drvdata(pdev, scpi_info); + platform_set_drvdata(pdev, scpi_drvinfo);
- if (scpi_info->is_legacy) { + if (scpi_drvinfo->is_legacy) { /* Replace with legacy variants */ scpi_ops.clk_set_val = legacy_scpi_clk_set_val; - scpi_info->commands = scpi_legacy_commands; + scpi_drvinfo->commands = scpi_legacy_commands;
/* Fill priority bitmap */ for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++) set_bit(legacy_hpriority_cmds[idx], - scpi_info->cmd_priority); + scpi_drvinfo->cmd_priority); }
- ret = scpi_init_versions(scpi_info); + scpi_info = scpi_drvinfo; + + ret = scpi_init_versions(scpi_drvinfo); if (ret) { dev_err(dev, "incorrect or no SCP firmware found\n"); + scpi_info = NULL; return ret; }
- if (scpi_info->is_legacy && !scpi_info->protocol_version && - !scpi_info->firmware_version) + if (scpi_drvinfo->is_legacy && !scpi_drvinfo->protocol_version && + !scpi_drvinfo->firmware_version) dev_info(dev, "SCP Protocol legacy pre-1.0 firmware\n"); else dev_info(dev, "SCP Protocol %lu.%lu Firmware %lu.%lu.%lu version\n", FIELD_GET(PROTO_REV_MAJOR_MASK, - scpi_info->protocol_version), + scpi_drvinfo->protocol_version), FIELD_GET(PROTO_REV_MINOR_MASK, - scpi_info->protocol_version), + scpi_drvinfo->protocol_version), FIELD_GET(FW_REV_MAJOR_MASK, - scpi_info->firmware_version), + scpi_drvinfo->firmware_version), FIELD_GET(FW_REV_MINOR_MASK, - scpi_info->firmware_version), + scpi_drvinfo->firmware_version), FIELD_GET(FW_REV_PATCH_MASK, - scpi_info->firmware_version)); - scpi_info->scpi_ops = &scpi_ops; + scpi_drvinfo->firmware_version)); + + scpi_drvinfo->scpi_ops = &scpi_ops;
- return devm_of_platform_populate(dev); + ret = devm_of_platform_populate(dev); + if (ret) + scpi_info = NULL; + + return ret; }
static const struct of_device_id scpi_of_match[] = {