* [PATCH] nvme: Enter string size calculation “subsysnqn”
@ 2024-12-26 10:45 Denis Arefev
2025-01-03 7:01 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Denis Arefev @ 2024-12-26 10:45 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Sagi Grimberg, Chaitanya Kulkarni, Hannes Reinecke, Keith Busch,
linux-nvme, linux-kernel, syzbot+a84181c81389771eb46a
When memory is allocated, the size of the string
is calculated nvmet_subsys_alloc(...).
When memory was accessed, constant size was used.
Fixes: 95409e277d83 ("nvmet: implement unique discovery NQN")
Reported-by: syzbot+a84181c81389771eb46a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a84181c81389771eb46a
Signed-off-by: Denis Arefev <arefev@swemel.ru>
---
drivers/nvme/target/configfs.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index eeee9e9b854c..2f74204d000e 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -2247,14 +2247,15 @@ static struct config_group nvmet_hosts_group;
static ssize_t nvmet_root_discovery_nqn_show(struct config_item *item,
char *page)
{
- return snprintf(page, PAGE_SIZE, "%s\n", nvmet_disc_subsys->subsysnqn);
+ return snprintf(page, strnlen(nvmet_disc_subsys->subsysnqn, PAGE_SIZE),
+ "%s\n", nvmet_disc_subsys->subsysnqn);
}
static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
const char *page, size_t count)
{
struct list_head *entry;
- size_t len;
+ size_t len, nqn_len;
len = strcspn(page, "\n");
if (!len || len > NVMF_NQN_FIELD_LEN - 1)
@@ -2271,8 +2272,9 @@ static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
return -EINVAL;
}
}
- memset(nvmet_disc_subsys->subsysnqn, 0, NVMF_NQN_FIELD_LEN);
- memcpy(nvmet_disc_subsys->subsysnqn, page, len);
+ nqn_len = strnlen(nvmet_disc_subsys->subsysnqn, NVMF_NQN_SIZE);
+ memset(nvmet_disc_subsys->subsysnqn, 0, nqn_len);
+ memcpy(nvmet_disc_subsys->subsysnqn, page, nqn_len);
up_write(&nvmet_config_sem);
return len;
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] nvme: Enter string size calculation “subsysnqn”
2024-12-26 10:45 [PATCH] nvme: Enter string size calculation “subsysnqn” Denis Arefev
@ 2025-01-03 7:01 ` Christoph Hellwig
2025-01-03 17:50 ` Caleb Sander
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2025-01-03 7:01 UTC (permalink / raw)
To: Denis Arefev
Cc: Christoph Hellwig, Sagi Grimberg, Chaitanya Kulkarni,
Hannes Reinecke, Keith Busch, linux-nvme, linux-kernel,
syzbot+a84181c81389771eb46a
On Thu, Dec 26, 2024 at 01:45:35PM +0300, Denis Arefev wrote:
> When memory is allocated, the size of the string
> is calculated nvmet_subsys_alloc(...).
s/is/is in/ ?
> When memory was accessed, constant size was used.
>
> Fixes: 95409e277d83 ("nvmet: implement unique discovery NQN")
> Reported-by: syzbot+a84181c81389771eb46a@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=a84181c81389771eb46a
> Signed-off-by: Denis Arefev <arefev@swemel.ru>
> ---
> drivers/nvme/target/configfs.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index eeee9e9b854c..2f74204d000e 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -2247,14 +2247,15 @@ static struct config_group nvmet_hosts_group;
> static ssize_t nvmet_root_discovery_nqn_show(struct config_item *item,
> char *page)
> {
> - return snprintf(page, PAGE_SIZE, "%s\n", nvmet_disc_subsys->subsysnqn);
> + return snprintf(page, strnlen(nvmet_disc_subsys->subsysnqn, PAGE_SIZE),
> + "%s\n", nvmet_disc_subsys->subsysnqn);
This doesn't really make sense as %s already calculates the length
of the string internally.
> }
>
> static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
> const char *page, size_t count)
> {
> struct list_head *entry;
> - size_t len;
> + size_t len, nqn_len;
>
> len = strcspn(page, "\n");
> if (!len || len > NVMF_NQN_FIELD_LEN - 1)
> @@ -2271,8 +2272,9 @@ static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
> return -EINVAL;
> }
> }
> - memset(nvmet_disc_subsys->subsysnqn, 0, NVMF_NQN_FIELD_LEN);
> - memcpy(nvmet_disc_subsys->subsysnqn, page, len);
> + nqn_len = strnlen(nvmet_disc_subsys->subsysnqn, NVMF_NQN_SIZE);
> + memset(nvmet_disc_subsys->subsysnqn, 0, nqn_len);
> + memcpy(nvmet_disc_subsys->subsysnqn, page, nqn_len);
The memset should still happen for the entire field, only the copy
needs to me limited.
But i really wonder if we should do away with this mess and just
use kmemdup()ed allocations for the nqns.
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] nvme: Enter string size calculation “subsysnqn”
2025-01-03 7:01 ` Christoph Hellwig
@ 2025-01-03 17:50 ` Caleb Sander
0 siblings, 0 replies; 3+ messages in thread
From: Caleb Sander @ 2025-01-03 17:50 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Denis Arefev, Sagi Grimberg, Chaitanya Kulkarni, Hannes Reinecke,
Keith Busch, linux-nvme, linux-kernel,
syzbot+a84181c81389771eb46a
The bug has already been fixed in commit 4db3d750ac7e ("nvmet: Don't
overflow subsysnqn"). It is using the kmemdup() approach (technically,
kstrndup()) suggested by Christoph.
On Thu, Jan 2, 2025 at 11:02 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Thu, Dec 26, 2024 at 01:45:35PM +0300, Denis Arefev wrote:
> > When memory is allocated, the size of the string
> > is calculated nvmet_subsys_alloc(...).
>
> s/is/is in/ ?
>
> > When memory was accessed, constant size was used.
> >
> > Fixes: 95409e277d83 ("nvmet: implement unique discovery NQN")
> > Reported-by: syzbot+a84181c81389771eb46a@syzkaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=a84181c81389771eb46a
> > Signed-off-by: Denis Arefev <arefev@swemel.ru>
> > ---
> > drivers/nvme/target/configfs.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> > index eeee9e9b854c..2f74204d000e 100644
> > --- a/drivers/nvme/target/configfs.c
> > +++ b/drivers/nvme/target/configfs.c
> > @@ -2247,14 +2247,15 @@ static struct config_group nvmet_hosts_group;
> > static ssize_t nvmet_root_discovery_nqn_show(struct config_item *item,
> > char *page)
> > {
> > - return snprintf(page, PAGE_SIZE, "%s\n", nvmet_disc_subsys->subsysnqn);
> > + return snprintf(page, strnlen(nvmet_disc_subsys->subsysnqn, PAGE_SIZE),
> > + "%s\n", nvmet_disc_subsys->subsysnqn);
>
> This doesn't really make sense as %s already calculates the length
> of the string internally.
>
> > }
> >
> > static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
> > const char *page, size_t count)
> > {
> > struct list_head *entry;
> > - size_t len;
> > + size_t len, nqn_len;
> >
> > len = strcspn(page, "\n");
> > if (!len || len > NVMF_NQN_FIELD_LEN - 1)
> > @@ -2271,8 +2272,9 @@ static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
> > return -EINVAL;
> > }
> > }
> > - memset(nvmet_disc_subsys->subsysnqn, 0, NVMF_NQN_FIELD_LEN);
> > - memcpy(nvmet_disc_subsys->subsysnqn, page, len);
> > + nqn_len = strnlen(nvmet_disc_subsys->subsysnqn, NVMF_NQN_SIZE);
> > + memset(nvmet_disc_subsys->subsysnqn, 0, nqn_len);
> > + memcpy(nvmet_disc_subsys->subsysnqn, page, nqn_len);
>
> The memset should still happen for the entire field, only the copy
> needs to me limited.
>
> But i really wonder if we should do away with this mess and just
> use kmemdup()ed allocations for the nqns.
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-01-03 17:50 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-12-26 10:45 [PATCH] nvme: Enter string size calculation “subsysnqn” Denis Arefev
2025-01-03 7:01 ` Christoph Hellwig
2025-01-03 17:50 ` Caleb Sander
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox