sugar/linux
1
0
Fork 0
Code Activity

tpm2-sessions: Fix tpm2_read_public range checks

Browse Source 
tpm2_read_public() has some rudimentary range checks but the function does
not ensure that the response buffer has enough bytes for the full TPMT_HA
payload.

Re-implement the function with necessary checks and validation, and return
name and name size for all handle types back to the caller.

Cc: stable@vger.kernel.org # v6.10+
Fixes: d0a25bb961 ("tpm: Add HMAC session name/handle append")
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jonathan McDowell <noodles@meta.com>
This commit is contained in:
Jarkko Sakkinen
2025-12-01 15:38:02 +02:00
parent 6e9722e9a7
commit bda1cbf73c
2 changed files with 53 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/char/tpm/tpm2-cmd.c
View File

@@ -11,8 +11,11 @@
* used by the kernel internally.
*/
#include "linux/dev_printk.h"
#include "linux/tpm.h"
#include "tpm.h"
#include <crypto/hash_info.h>
#include <linux/unaligned.h>
static bool disable_pcr_integrity;
module_param(disable_pcr_integrity, bool, 0444);

94
drivers/char/tpm/tpm2-sessions.c
View File

@@ -163,53 +163,61 @@ static int name_size(const u8 *name)
}
}
static int tpm2_parse_read_public(char *name, struct tpm_buf *buf)
static int tpm2_read_public(struct tpm_chip *chip, u32 handle, void *name)
{
struct tpm_header *head = (struct tpm_header *)buf->data;
u32 mso = tpm2_handle_mso(handle);
off_t offset = TPM_HEADER_SIZE;
u32 tot_len = be32_to_cpu(head->length);
int ret;
u32 val;
/* we're starting after the header so adjust the length */
tot_len -= TPM_HEADER_SIZE;
/* skip public */
val = tpm_buf_read_u16(buf, &offset);
if (val > tot_len)
return -EINVAL;
offset += val;
/* name */
val = tpm_buf_read_u16(buf, &offset);
ret = name_size(&buf->data[offset]);
if (ret < 0)
return ret;
if (val != ret)
return -EINVAL;
memcpy(name, &buf->data[offset], val);
/* forget the rest */
return 0;
}
static int tpm2_read_public(struct tpm_chip *chip, u32 handle, char *name)
{
int rc, name_size_alg;
struct tpm_buf buf;
int rc;
if (mso != TPM2_MSO_PERSISTENT && mso != TPM2_MSO_VOLATILE &&
mso != TPM2_MSO_NVRAM) {
memcpy(name, &handle, sizeof(u32));
return sizeof(u32);
}
rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_READ_PUBLIC);
if (rc)
return rc;
tpm_buf_append_u32(&buf, handle);
rc = tpm_transmit_cmd(chip, &buf, 0, "read public");
if (rc == TPM2_RC_SUCCESS)
rc = tpm2_parse_read_public(name, &buf);
tpm_buf_destroy(&buf);
rc = tpm_transmit_cmd(chip, &buf, 0, "TPM2_ReadPublic");
if (rc) {
tpm_buf_destroy(&buf);
return tpm_ret_to_err(rc);
}
return rc;
/* Skip TPMT_PUBLIC: */
offset += tpm_buf_read_u16(&buf, &offset);
/*
* Ensure space for the length field of TPM2B_NAME and hashAlg field of
* TPMT_HA (the extra four bytes).
*/
if (offset + 4 > tpm_buf_length(&buf)) {
tpm_buf_destroy(&buf);
return -EIO;
}
rc = tpm_buf_read_u16(&buf, &offset);
name_size_alg = name_size(&buf.data[offset]);
if (name_size_alg < 0)
return name_size_alg;
if (rc != name_size_alg) {
tpm_buf_destroy(&buf);
return -EIO;
}
if (offset + rc > tpm_buf_length(&buf)) {
tpm_buf_destroy(&buf);
return -EIO;
}
memcpy(name, &buf.data[offset], rc);
return name_size_alg;
}
#endif /* CONFIG_TCG_TPM2_HMAC */
@@ -243,6 +251,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
#ifdef CONFIG_TCG_TPM2_HMAC
enum tpm2_mso_type mso = tpm2_handle_mso(handle);
struct tpm2_auth *auth;
u16 name_size_alg;
int slot;
int ret;
#endif
@@ -273,8 +282,10 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
mso == TPM2_MSO_NVRAM) {
if (!name) {
ret = tpm2_read_public(chip, handle, auth->name[slot]);
if (ret)
if (ret < 0)
goto err;
name_size_alg = ret;
}
} else {
if (name) {
@@ -286,13 +297,8 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}
auth->name_h[slot] = handle;
if (name) {
ret = name_size(name);
if (ret < 0)
goto err;
memcpy(auth->name[slot], name, ret);
}
if (name)
memcpy(auth->name[slot], name, name_size_alg);
#endif
return 0;