Re: [PATCH 1/1] dm-verity: fix a memory leak if some arguments are specified multiple times

Greg, Shuah, Mikulas, This is my first attempt at backporting an upstream patch (Part of Linux kernel Bug Fixing Summer 2025). Please feel free to correct me, I'm open to feedback. I see I've added two From section, if that requires me to resend a v2 of the patch, please let me know.

On 06.06.2025 01:41, Brahmajit Das wrote:

From: Mikulas Patocka mpatocka@redhat.com

From: Mikulas Patocka mpatocka@redhat.com

[ Upstream commit 66be40a14e496689e1f0add50118408e22c96169 ]

If some of the arguments "check_at_most_once", "ignore_zero_blocks", "use_fec_from_device", "root_hash_sig_key_desc" were specified more than once on the target line, a memory leak would happen.

This commit fixes the memory leak. It also fixes error handling in verity_verify_sig_parse_opt_args.

Signed-off-by: Mikulas Patocka mpatocka@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Brahmajit Das listout@listout.xyz

---

drivers/md/dm-verity-fec.c | 4 ++++ drivers/md/dm-verity-target.c | 8 +++++++- drivers/md/dm-verity-verify-sig.c | 17 +++++++++++++---- 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index 0c41949db784..631a887b487c 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -593,6 +593,10 @@ int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, (*argc)--; if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {

• if (v->fec->dev) {
  

• 	ti->error = "FEC device already specified";
  

• 	return -EINVAL;
  

• }
  

  r = dm_get_device(ti, arg_value, BLK_OPEN_READ, &v->fec->dev); if (r) { ti->error = "FEC device lookup failed";

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index 3c427f18a04b..ed49bcbd224f 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -1120,6 +1120,9 @@ static int verity_alloc_most_once(struct dm_verity *v) { struct dm_target *ti = v->ti;

• if (v->validated_blocks)

• return 0;
  

• /* the bitset can only handle INT_MAX blocks */ if (v->data_blocks > INT_MAX) { ti->error = "device too large to use check_at_most_once";

@@ -1143,6 +1146,9 @@ static int verity_alloc_zero_digest(struct dm_verity *v) struct dm_verity_io *io; u8 *zero_data;

• if (v->zero_digest)

• return 0;
  

• v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);

if (!v->zero_digest) @@ -1577,7 +1583,7 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv) goto bad; }

• /* Root hash signature is a optional parameter*/

• /* Root hash signature is an optional parameter */ r = verity_verify_root_hash(root_hash_digest_to_validate, strlen(root_hash_digest_to_validate), verify_args.sig,

diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c index a9e2c6c0a33c..d5261a0e4232 100644 --- a/drivers/md/dm-verity-verify-sig.c +++ b/drivers/md/dm-verity-verify-sig.c @@ -71,9 +71,14 @@ int verity_verify_sig_parse_opt_args(struct dm_arg_set *as, const char *arg_name) { struct dm_target *ti = v->ti;

• int ret = 0;

• int ret; const char *sig_key = NULL;

• if (v->signature_key_desc) {

• ti->error = DM_VERITY_VERIFY_ERR("root_hash_sig_key_desc already specified");
  

• return -EINVAL;
  

• }
• if (!*argc) { ti->error = DM_VERITY_VERIFY_ERR("Signature key not specified"); return -EINVAL;

@@ -83,14 +88,18 @@ int verity_verify_sig_parse_opt_args(struct dm_arg_set *as, (*argc)--; ret = verity_verify_get_sig_from_key(sig_key, sig_opts);

• if (ret < 0)

• if (ret < 0) { ti->error = DM_VERITY_VERIFY_ERR("Invalid key specified");

• return ret;
  

• }

v->signature_key_desc = kstrdup(sig_key, GFP_KERNEL);

• if (!v->signature_key_desc)

• if (!v->signature_key_desc) {

• ti->error = DM_VERITY_VERIFY_ERR("Could not allocate memory for signature key");
  

  return -ENOMEM;
• }

• return ret;

• return 0;

} /* -- 2.49.0