From 951ef0e19f0736b45d1c4d81f4dfa04a43f87df5 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Fri, 8 Dec 2017 23:59:49 +0000 Subject: [PATCH 1/2] ACPI: CPPC: remove initial assignment of pcc_ss_data The initialization of pcc_ss_data from pcc_data[pcc_ss_id] before pcc_ss_id is being range checked could lead to an out-of-bounds array read. This very same initialization is also being performed after the range check on pcc_ss_id, so we can just remove this problematic and also redundant assignment to fix the issue. Detected by cppcheck: warning: Value stored to 'pcc_ss_data' during its initialization is never read Fixes: 85b1407bf6d2 (ACPI / CPPC: Make CPPC ACPI driver aware of PCC subspace IDs) Signed-off-by: Colin Ian King Signed-off-by: Rafael J. Wysocki --- drivers/acpi/cppc_acpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 30e84cc600ae..06ea4749ebd9 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1171,7 +1171,7 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu); struct cpc_register_resource *desired_reg; int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); - struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id]; + struct cppc_pcc_data *pcc_ss_data; int ret = 0; if (!cpc_desc || pcc_ss_id < 0) { From bb82e0b4a7e96494f0c1004ce50cec3d7b5fb3d1 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 14 Dec 2017 13:31:16 +0100 Subject: [PATCH 2/2] ACPI: APEI / ERST: Fix missing error handling in erst_reader() The commit f6f828513290 ("pstore: pass allocated memory region back to caller") changed the check of the return value from erst_read() in erst_reader() in the following way: if (len == -ENOENT) goto skip; - else if (len < 0) { - rc = -1; + else if (len < sizeof(*rcd)) { + rc = -EIO; goto out; This introduced another bug: since the comparison with sizeof() is cast to unsigned, a negative len value doesn't hit any longer. As a result, when an error is returned from erst_read(), the code falls through, and it may eventually lead to some weird thing like memory corruption. This patch adds the negative error value check more explicitly for addressing the issue. Fixes: f6f828513290 (pstore: pass allocated memory region back to caller) Cc: All applicable Tested-by: Jerry Tang Signed-off-by: Takashi Iwai Acked-by: Kees Cook Reviewed-by: Borislav Petkov Signed-off-by: Rafael J. Wysocki --- drivers/acpi/apei/erst.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c index 6742f6c68034..9bff853e85f3 100644 --- a/drivers/acpi/apei/erst.c +++ b/drivers/acpi/apei/erst.c @@ -1007,7 +1007,7 @@ static ssize_t erst_reader(struct pstore_record *record) /* The record may be cleared by others, try read next record */ if (len == -ENOENT) goto skip; - else if (len < sizeof(*rcd)) { + else if (len < 0 || len < sizeof(*rcd)) { rc = -EIO; goto out; }