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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /lib/digsig.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'lib/digsig.c')
-rw-r--r--lib/digsig.c244
1 files changed, 244 insertions, 0 deletions
diff --git a/lib/digsig.c b/lib/digsig.c
new file mode 100644
index 000000000..9dd319c12
--- /dev/null
+++ b/lib/digsig.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2011 Nokia Corporation
+ * Copyright (C) 2011 Intel Corporation
+ *
+ * Author:
+ * Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
+ * <dmitry.kasatkin@intel.com>
+ *
+ * File: sign.c
+ * implements signature (RSA) verification
+ * pkcs decoding is based on LibTomCrypt code
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/key.h>
+#include <crypto/sha1.h>
+#include <keys/user-type.h>
+#include <linux/mpi.h>
+#include <linux/digsig.h>
+
+static const char *pkcs_1_v1_5_decode_emsa(const unsigned char *msg,
+ unsigned long msglen,
+ unsigned long modulus_bitlen,
+ unsigned long *outlen)
+{
+ unsigned long modulus_len, ps_len, i;
+
+ modulus_len = (modulus_bitlen >> 3) + (modulus_bitlen & 7 ? 1 : 0);
+
+ /* test message size */
+ if ((msglen > modulus_len) || (modulus_len < 11))
+ return NULL;
+
+ /* separate encoded message */
+ if (msg[0] != 0x00 || msg[1] != 0x01)
+ return NULL;
+
+ for (i = 2; i < modulus_len - 1; i++)
+ if (msg[i] != 0xFF)
+ break;
+
+ /* separator check */
+ if (msg[i] != 0)
+ /* There was no octet with hexadecimal value 0x00
+ to separate ps from m. */
+ return NULL;
+
+ ps_len = i - 2;
+
+ *outlen = (msglen - (2 + ps_len + 1));
+
+ return msg + 2 + ps_len + 1;
+}
+
+/*
+ * RSA Signature verification with public key
+ */
+static int digsig_verify_rsa(struct key *key,
+ const char *sig, int siglen,
+ const char *h, int hlen)
+{
+ int err = -EINVAL;
+ unsigned long len;
+ unsigned long mlen, mblen;
+ unsigned nret, l;
+ int head, i;
+ unsigned char *out1 = NULL;
+ const char *m;
+ MPI in = NULL, res = NULL, pkey[2];
+ uint8_t *p, *datap;
+ const uint8_t *endp;
+ const struct user_key_payload *ukp;
+ struct pubkey_hdr *pkh;
+
+ down_read(&key->sem);
+ ukp = user_key_payload_locked(key);
+
+ if (!ukp) {
+ /* key was revoked before we acquired its semaphore */
+ err = -EKEYREVOKED;
+ goto err1;
+ }
+
+ if (ukp->datalen < sizeof(*pkh))
+ goto err1;
+
+ pkh = (struct pubkey_hdr *)ukp->data;
+
+ if (pkh->version != 1)
+ goto err1;
+
+ if (pkh->algo != PUBKEY_ALGO_RSA)
+ goto err1;
+
+ if (pkh->nmpi != 2)
+ goto err1;
+
+ datap = pkh->mpi;
+ endp = ukp->data + ukp->datalen;
+
+ for (i = 0; i < pkh->nmpi; i++) {
+ unsigned int remaining = endp - datap;
+ pkey[i] = mpi_read_from_buffer(datap, &remaining);
+ if (IS_ERR(pkey[i])) {
+ err = PTR_ERR(pkey[i]);
+ goto err;
+ }
+ datap += remaining;
+ }
+
+ mblen = mpi_get_nbits(pkey[0]);
+ mlen = DIV_ROUND_UP(mblen, 8);
+
+ if (mlen == 0) {
+ err = -EINVAL;
+ goto err;
+ }
+
+ err = -ENOMEM;
+
+ out1 = kzalloc(mlen, GFP_KERNEL);
+ if (!out1)
+ goto err;
+
+ nret = siglen;
+ in = mpi_read_from_buffer(sig, &nret);
+ if (IS_ERR(in)) {
+ err = PTR_ERR(in);
+ goto err;
+ }
+
+ res = mpi_alloc(mpi_get_nlimbs(in) * 2);
+ if (!res)
+ goto err;
+
+ err = mpi_powm(res, in, pkey[1], pkey[0]);
+ if (err)
+ goto err;
+
+ if (mpi_get_nlimbs(res) * BYTES_PER_MPI_LIMB > mlen) {
+ err = -EINVAL;
+ goto err;
+ }
+
+ p = mpi_get_buffer(res, &l, NULL);
+ if (!p) {
+ err = -EINVAL;
+ goto err;
+ }
+
+ len = mlen;
+ head = len - l;
+ memcpy(out1 + head, p, l);
+
+ kfree(p);
+
+ m = pkcs_1_v1_5_decode_emsa(out1, len, mblen, &len);
+
+ if (!m || len != hlen || memcmp(m, h, hlen))
+ err = -EINVAL;
+
+err:
+ mpi_free(in);
+ mpi_free(res);
+ kfree(out1);
+ while (--i >= 0)
+ mpi_free(pkey[i]);
+err1:
+ up_read(&key->sem);
+
+ return err;
+}
+
+/**
+ * digsig_verify() - digital signature verification with public key
+ * @keyring: keyring to search key in
+ * @sig: digital signature
+ * @siglen: length of the signature
+ * @data: data
+ * @datalen: length of the data
+ *
+ * Returns 0 on success, -EINVAL otherwise
+ *
+ * Verifies data integrity against digital signature.
+ * Currently only RSA is supported.
+ * Normally hash of the content is used as a data for this function.
+ *
+ */
+int digsig_verify(struct key *keyring, const char *sig, int siglen,
+ const char *data, int datalen)
+{
+ struct signature_hdr *sh = (struct signature_hdr *)sig;
+ struct sha1_ctx ctx;
+ unsigned char hash[SHA1_DIGEST_SIZE];
+ struct key *key;
+ char name[20];
+ int err;
+
+ if (siglen < sizeof(*sh) + 2)
+ return -EINVAL;
+
+ if (sh->algo != PUBKEY_ALGO_RSA)
+ return -ENOTSUPP;
+
+ sprintf(name, "%llX", __be64_to_cpup((uint64_t *)sh->keyid));
+
+ if (keyring) {
+ /* search in specific keyring */
+ key_ref_t kref;
+ kref = keyring_search(make_key_ref(keyring, 1UL),
+ &key_type_user, name, true);
+ if (IS_ERR(kref))
+ key = ERR_CAST(kref);
+ else
+ key = key_ref_to_ptr(kref);
+ } else {
+ key = request_key(&key_type_user, name, NULL);
+ }
+ if (IS_ERR(key)) {
+ pr_err("key not found, id: %s\n", name);
+ return PTR_ERR(key);
+ }
+
+ sha1_init(&ctx);
+ sha1_update(&ctx, data, datalen);
+ sha1_update(&ctx, sig, sizeof(*sh));
+ sha1_final(&ctx, hash);
+
+ /* pass signature mpis address */
+ err = digsig_verify_rsa(key, sig + sizeof(*sh), siglen - sizeof(*sh),
+ hash, sizeof(hash));
+
+ key_put(key);
+
+ return err ? -EINVAL : 0;
+}
+EXPORT_SYMBOL_GPL(digsig_verify);
+
+MODULE_LICENSE("GPL");