'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.
Cc: stable@vger.kernel.org # v6.10+ Fixes: d0a25bb961e6 ("tpm: Add HMAC session name/handle append") Signed-off-by: Jarkko Sakkinen jarkko@kernel.org --- drivers/char/tpm/tpm2-cmd.c | 3 ++ drivers/char/tpm/tpm2-sessions.c | 77 +++++++++++++++++--------------- 2 files changed, 44 insertions(+), 36 deletions(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c index 4473b81122e8..58a8477cda85 100644 --- a/drivers/char/tpm/tpm2-cmd.c +++ b/drivers/char/tpm/tpm2-cmd.c @@ -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); diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c index 33ad0d668e1a..afbca03f639e 100644 --- a/drivers/char/tpm/tpm2-sessions.c +++ b/drivers/char/tpm/tpm2-sessions.c @@ -164,54 +164,59 @@ static int name_size(const u8 *name) return -EINVAL; }
-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; + struct tpm_buf buf; + int rc, rc2;
- if (val != ret) + if (mso != TPM2_MSO_PERSISTENT && mso != TPM2_MSO_VOLATILE && + mso != TPM2_MSO_NVRAM) 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) -{ - struct tpm_buf buf; - int rc; - 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); + rc2 = name_size(&buf.data[offset]); + + if (rc2 < 0) + return rc2; + + if (rc != rc2) { + 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 0; } #endif /* CONFIG_TCG_TPM2_HMAC */