| Message ID | 20240913231954.20081-2-gourry@gourry.net |
|---|---|
| State | New |
| Headers | show |
| Series | libstub,tpm: fix small bugs and improve error reporting | expand |
On Sat, 14 Sept 2024 at 02:20, Gregory Price <gourry@gourry.net> wrote: > > A prior bugfix that fixes a signed/unsigned error causes > another signed unsigned error. > > A situation where log_tbl->size is invalid can cause the > size passed to memblock_reserve to become negative. > > log_size from the main event log is an unsigned int, and > the code reduces to the following > > u64 value = (int)unsigned_value; > > This results in sign extension, and the value sent to > memblock_reserve becomes effectively negative. > > Fixes: be59d57f9806 ("efi/tpm: Fix sanity check of unsigned tbl_size being less than zero") > Signed-off-by: Gregory Price <gourry@gourry.net> > --- > drivers/firmware/efi/tpm.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c > index e8d69bd548f3..9c3613e6af15 100644 > --- a/drivers/firmware/efi/tpm.c > +++ b/drivers/firmware/efi/tpm.c > @@ -40,7 +40,8 @@ int __init efi_tpm_eventlog_init(void) > { > struct linux_efi_tpm_eventlog *log_tbl; > struct efi_tcg2_final_events_table *final_tbl; > - int tbl_size; > + unsigned int tbl_size; nit, perhaps u32 is better here > + int final_tbl_size; > int ret = 0; > > if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) { > @@ -80,26 +81,26 @@ int __init efi_tpm_eventlog_init(void) > goto out; > } > > - tbl_size = 0; > + final_tbl_size = 0; > if (final_tbl->nr_events != 0) { > void *events = (void *)efi.tpm_final_log > + sizeof(final_tbl->version) > + sizeof(final_tbl->nr_events); > > - tbl_size = tpm2_calc_event_log_size(events, > - final_tbl->nr_events, > - log_tbl->log); > + final_tbl_size = tpm2_calc_event_log_size(events, > + final_tbl->nr_events, > + log_tbl->log); > } > > - if (tbl_size < 0) { > + if (final_tbl_size < 0) { > pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n"); > ret = -EINVAL; > goto out_calc; > } > > memblock_reserve(efi.tpm_final_log, > - tbl_size + sizeof(*final_tbl)); > - efi_tpm_final_log_size = tbl_size; > + final_tbl_size + sizeof(*final_tbl)); > + efi_tpm_final_log_size = final_tbl_size; > > out_calc: > early_memunmap(final_tbl, sizeof(*final_tbl)); > -- > 2.43.0 > Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c index e8d69bd548f3..9c3613e6af15 100644 --- a/drivers/firmware/efi/tpm.c +++ b/drivers/firmware/efi/tpm.c @@ -40,7 +40,8 @@ int __init efi_tpm_eventlog_init(void) { struct linux_efi_tpm_eventlog *log_tbl; struct efi_tcg2_final_events_table *final_tbl; - int tbl_size; + unsigned int tbl_size; + int final_tbl_size; int ret = 0; if (efi.tpm_log == EFI_INVALID_TABLE_ADDR) { @@ -80,26 +81,26 @@ int __init efi_tpm_eventlog_init(void) goto out; } - tbl_size = 0; + final_tbl_size = 0; if (final_tbl->nr_events != 0) { void *events = (void *)efi.tpm_final_log + sizeof(final_tbl->version) + sizeof(final_tbl->nr_events); - tbl_size = tpm2_calc_event_log_size(events, - final_tbl->nr_events, - log_tbl->log); + final_tbl_size = tpm2_calc_event_log_size(events, + final_tbl->nr_events, + log_tbl->log); } - if (tbl_size < 0) { + if (final_tbl_size < 0) { pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n"); ret = -EINVAL; goto out_calc; } memblock_reserve(efi.tpm_final_log, - tbl_size + sizeof(*final_tbl)); - efi_tpm_final_log_size = tbl_size; + final_tbl_size + sizeof(*final_tbl)); + efi_tpm_final_log_size = final_tbl_size; out_calc: early_memunmap(final_tbl, sizeof(*final_tbl));
A prior bugfix that fixes a signed/unsigned error causes another signed unsigned error. A situation where log_tbl->size is invalid can cause the size passed to memblock_reserve to become negative. log_size from the main event log is an unsigned int, and the code reduces to the following u64 value = (int)unsigned_value; This results in sign extension, and the value sent to memblock_reserve becomes effectively negative. Fixes: be59d57f9806 ("efi/tpm: Fix sanity check of unsigned tbl_size being less than zero") Signed-off-by: Gregory Price <gourry@gourry.net> --- drivers/firmware/efi/tpm.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)