[PATCH] nvme-fabrics: fix DHCHAP secret leak on parse failure

[PATCH] nvme-fabrics: fix DHCHAP secret leak on parse failure

[raoxu]

From: Xu Rao <raoxu@uniontech.com>

nvmf_parse_options() duplicates dhchap_secret and dhchap_ctrl_secret
with match_strdup() before validating the DHHC-1: representation.

If validation fails, the parser returns -EINVAL before the temporary
string in p is assigned to opts->dhchap_secret or
opts->dhchap_ctrl_secret. nvmf_create_ctrl() subsequently frees opts,
but nvmf_free_options() cannot release the unassigned temporary string.
Each rejected option therefore leaks one allocation.

This is easy to miss because valid secrets transfer ownership to opts
and are freed normally, while the malformed-secret path still returns
the expected -EINVAL to userspace.

With CONFIG_NVME_HOST_AUTH enabled, the leak is reachable before the
required-option checks and transport lookup. No NVMe-oF target or
working transport connection is required; for example, repeatedly
writing

	dhchap_secret=BAD

or

	dhchap_ctrl_secret=BAD

to /dev/nvme-fabrics deterministically takes the leaking parse path.

Free the temporary string before leaving both validation error paths.
Use kfree_sensitive() because the copied option may contain secret
material even when its representation is rejected, matching the
sensitive cleanup used for stored DHCHAP secrets.

Fixes: f50fff73d620 ("nvme: implement In-Band authentication")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Rao <raoxu@uniontech.com>
---
 drivers/nvme/host/fabrics.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index ac3d4f400601..736570b5fb34 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -1028,6 +1028,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			if (strlen(p) < 11 || strncmp(p, "DHHC-1:", 7)) {
 				pr_err("Invalid DH-CHAP secret %s\n", p);
+				kfree_sensitive(p);
 				ret = -EINVAL;
 				goto out;
 			}
@@ -1042,6 +1043,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			if (strlen(p) < 11 || strncmp(p, "DHHC-1:", 7)) {
 				pr_err("Invalid DH-CHAP secret %s\n", p);
+				kfree_sensitive(p);
 				ret = -EINVAL;
 				goto out;
 			}
--
2.50.1

Re: [PATCH] nvme-fabrics: fix DHCHAP secret leak on parse failure

[Christoph Hellwig]

On Thu, Aug 13, 2026 at 04:31:07PM +0800, raoxu wrote:
> From: Xu Rao <raoxu@uniontech.com>
> 
> nvmf_parse_options() duplicates dhchap_secret and dhchap_ctrl_secret
> with match_strdup() before validating the DHHC-1: representation.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Btw, I think the size and structure of nvmf_parse_options helped to
get to this.  If you are interested in a little improvement project
in this area, it would be nice to add a separate helper for the parsing
of each option so that the strdup allocations are limited to that
scope (and don't reuse the p variable used for the token).