4.14-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 45b14a4ffcc1e0b5caa246638f942cbe7eaea7ad ]
When checking a generic status block, we iterate over all the generic data blocks. The loop condition only checks that the start of the generic data block is valid (within estatus->data_length) but not the whole block. Because the size of data blocks (excluding error data) may vary depending on the revision and the revision is contained within the data block, ensure that enough of the current data block is valid before dereferencing any members otherwise an out-of-bounds access may occur if estatus->data_length is invalid.
This relies on the fact that struct acpi_hest_generic_data_v300 is a superset of the earlier version. Also rework the other checks to avoid potential underflow.
Signed-off-by: Ross Lagerwall ross.lagerwall@citrix.com Acked-by: Borislav Petkov bp@suse.de Tested-by: Tyler Baicar baicar.tyler@gmail.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/efi/cper.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c index d2fcafcea07e..ce23d5402bd6 100644 --- a/drivers/firmware/efi/cper.c +++ b/drivers/firmware/efi/cper.c @@ -641,19 +641,24 @@ EXPORT_SYMBOL_GPL(cper_estatus_check_header); int cper_estatus_check(const struct acpi_hest_generic_status *estatus) { struct acpi_hest_generic_data *gdata; - unsigned int data_len, gedata_len; + unsigned int data_len, record_size; int rc;
rc = cper_estatus_check_header(estatus); if (rc) return rc; + data_len = estatus->data_length;
apei_estatus_for_each_section(estatus, gdata) { - gedata_len = acpi_hest_get_error_length(gdata); - if (gedata_len > data_len - acpi_hest_get_size(gdata)) + if (sizeof(struct acpi_hest_generic_data) > data_len) + return -EINVAL; + + record_size = acpi_hest_get_record_size(gdata); + if (record_size > data_len) return -EINVAL; - data_len -= acpi_hest_get_record_size(gdata); + + data_len -= record_size; } if (data_len) return -EINVAL;