Re: FAILED: patch "[PATCH] tpm2-sessions: Fix tpm2_read_public range checks" failed to apply to 6.12-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Jan 08, 2026 at 02:35:57PM +0200, Jarkko Sakkinen wrote:
> On Mon, Dec 29, 2025 at 01:34:07PM +0100, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 6.12-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > To reproduce the conflict and resubmit, you may use the following commands:
> > 
> > git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
> > git checkout FETCH_HEAD
> > git cherry-pick -x bda1cbf73c6e241267c286427f2ed52b5735d872
> > # <resolve conflicts, build, test, etc.>
> > git commit -s
> > git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025122907-stream-lasso-ba6e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
> > 
> > Possible dependencies:
> > 
> > 
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> > From bda1cbf73c6e241267c286427f2ed52b5735d872 Mon Sep 17 00:00:00 2001
> > From: Jarkko Sakkinen <jarkko@kernel.org>
> > Date: Mon, 1 Dec 2025 15:38:02 +0200
> > Subject: [PATCH] tpm2-sessions: Fix tpm2_read_public range checks
> > 
> > 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: d0a25bb961e6 ("tpm: Add HMAC session name/handle append")
> > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> > Reviewed-by: Jonathan McDowell <noodles@meta.com>
> > 
> > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> > index be4a9c7f2e1a..34e3599f094f 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 385014dbca39..3f389e2f6f58 100644
> > --- a/drivers/char/tpm/tpm2-sessions.c
> > +++ b/drivers/char/tpm/tpm2-sessions.c
> > @@ -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;
> >  
> > 
> 
> This will apply on top of https://lore.kernel.org/linux-integrity/aV-kD5iKi9fwluU0@kernel.org/T/#t

Already in the last 6.12.y release.

thanks,

greg k-h