Commit 666c1a2c authored by Gunnar Kudrjavets's avatar Gunnar Kudrjavets Committed by Jarkko Sakkinen
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tpm: Fix auth session leak in tpm2_get_random() error path 



When tpm_buf_fill_hmac_session() fails inside the do-while loop in
tpm2_get_random(), the function returns directly after destroying the
buffer, without ending the auth session via tpm2_end_auth_session().

This leaks the TPM auth session resource. All other error paths within
the loop correctly reach the 'out' label which calls both
tpm_buf_destroy() and tpm2_end_auth_session().

Fix this by replacing the early return with a goto to the existing 'out'
label, which already handles both cleanup operations. The redundant
tpm_buf_destroy() call is removed since 'out' takes care of it.

Cc: stable@vger.kernel.org # v6.19+
Fixes: 6e9722e9 ("tpm2-sessions: Fix out of range indexing in name_size")
Signed-off-by: default avatarGunnar Kudrjavets <gunnarku@amazon.com>
Reviewed-by: default avatarJustinien Bouron <jbouron@amazon.com>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent bb7a4e3b

drivers/char/tpm/tpm2-cmd.c

+2 −4
Original line number Diff line number Diff line
@@ -295,10 +295,8 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max) 
		}

		tpm_buf_append_u16(&buf, num_bytes);

		err = tpm_buf_fill_hmac_session(chip, &buf);

		if (err) {

			tpm_buf_destroy(&buf);

			return err;

		}

		if (err)

			goto out;



		err = tpm_transmit_cmd(chip, &buf,

				       offsetof(struct tpm2_get_random_out,