* [PATCH] tee: fix register_shm_helper()
@ 2025-09-19 12:40 Jens Wiklander
2025-09-21 6:14 ` Masami Ichikawa
2025-09-22 4:11 ` Sumit Garg
0 siblings, 2 replies; 4+ messages in thread
From: Jens Wiklander @ 2025-09-19 12:40 UTC (permalink / raw)
To: linux-kernel, op-tee
Cc: Sumit Garg, Jerome Forissier, Jens Wiklander, stable,
Masami Ichikawa
In register_shm_helper(), fix incorrect error handling for a call to
iov_iter_extract_pages(). A case is missing for when
iov_iter_extract_pages() only got some pages and return a number larger
than 0, but not the requested amount.
This fixes a possible NULL pointer dereference following a bad input from
ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped.
Cc: stable@vger.kernel.org
Reported-by: Masami Ichikawa <masami256@gmail.com>
Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=u9W+-g@mail.gmail.com/
Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration")
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
drivers/tee/tee_shm.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index daf6e5cfd59a..6ed7d030f4ed 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,
&off);
- if (unlikely(len <= 0)) {
+ if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) {
+ if (len > 0) {
+ /*
+ * If we only got a few pages, update to release
+ * the correct amount below.
+ */
+ shm->num_pages = len / PAGE_SIZE;
+ ret = ERR_PTR(-ENOMEM);
+ goto err_put_shm_pages;
+ }
ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM);
goto err_free_shm_pages;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] tee: fix register_shm_helper() 2025-09-19 12:40 [PATCH] tee: fix register_shm_helper() Jens Wiklander @ 2025-09-21 6:14 ` Masami Ichikawa 2025-09-22 4:11 ` Sumit Garg 1 sibling, 0 replies; 4+ messages in thread From: Masami Ichikawa @ 2025-09-21 6:14 UTC (permalink / raw) To: Jens Wiklander; +Cc: linux-kernel, op-tee, Sumit Garg, Jerome Forissier, stable Hi Jens, On Fri, Sep 19, 2025 at 9:42 PM Jens Wiklander <jens.wiklander@linaro.org> wrote: > > In register_shm_helper(), fix incorrect error handling for a call to > iov_iter_extract_pages(). A case is missing for when > iov_iter_extract_pages() only got some pages and return a number larger > than 0, but not the requested amount. > > This fixes a possible NULL pointer dereference following a bad input from > ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped. > > Cc: stable@vger.kernel.org > Reported-by: Masami Ichikawa <masami256@gmail.com> > Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=u9W+-g@mail.gmail.com/ > Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration") > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > --- > drivers/tee/tee_shm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index daf6e5cfd59a..6ed7d030f4ed 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, > > len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0, > &off); > - if (unlikely(len <= 0)) { > + if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { > + if (len > 0) { > + /* > + * If we only got a few pages, update to release > + * the correct amount below. > + */ > + shm->num_pages = len / PAGE_SIZE; > + ret = ERR_PTR(-ENOMEM); > + goto err_put_shm_pages; > + } > ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); > goto err_free_shm_pages; > } > -- > 2.43.0 > Thank you for the patch. I confirmed that the patch fixes a kernel crash caused by a NULL pointer dereference. Tested-by: Masami Ichikawa <masami256@gmail.com> Regrads, -- Masami Ichikawa ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tee: fix register_shm_helper() 2025-09-19 12:40 [PATCH] tee: fix register_shm_helper() Jens Wiklander 2025-09-21 6:14 ` Masami Ichikawa @ 2025-09-22 4:11 ` Sumit Garg 2025-09-22 6:39 ` Jens Wiklander 1 sibling, 1 reply; 4+ messages in thread From: Sumit Garg @ 2025-09-22 4:11 UTC (permalink / raw) To: Jens Wiklander Cc: linux-kernel, op-tee, Jerome Forissier, stable, Masami Ichikawa On Fri, Sep 19, 2025 at 02:40:16PM +0200, Jens Wiklander wrote: > In register_shm_helper(), fix incorrect error handling for a call to > iov_iter_extract_pages(). A case is missing for when > iov_iter_extract_pages() only got some pages and return a number larger > than 0, but not the requested amount. > > This fixes a possible NULL pointer dereference following a bad input from > ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped. > > Cc: stable@vger.kernel.org > Reported-by: Masami Ichikawa <masami256@gmail.com> > Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=u9W+-g@mail.gmail.com/ > Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration") > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > --- > drivers/tee/tee_shm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index daf6e5cfd59a..6ed7d030f4ed 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, > > len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0, > &off); > - if (unlikely(len <= 0)) { > + if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { > + if (len > 0) { > + /* > + * If we only got a few pages, update to release > + * the correct amount below. > + */ > + shm->num_pages = len / PAGE_SIZE; > + ret = ERR_PTR(-ENOMEM); > + goto err_put_shm_pages; > + } > ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); > goto err_free_shm_pages; > } Rather than operating directly on "len" without checking for error code first doesn't seems appropriate to me. How about following diff instead? diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index daf6e5cfd59a..cb52bc51943e 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -319,6 +319,14 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, if (unlikely(len <= 0)) { ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); goto err_free_shm_pages; + } else if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { + /* + * If we only got a few pages, update to release the correct + * amount below. + */ + shm->num_pages = len / PAGE_SIZE; + ret = ERR_PTR(-ENOMEM); + goto err_put_shm_pages; } /* -Sumit > -- > 2.43.0 > ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] tee: fix register_shm_helper() 2025-09-22 4:11 ` Sumit Garg @ 2025-09-22 6:39 ` Jens Wiklander 0 siblings, 0 replies; 4+ messages in thread From: Jens Wiklander @ 2025-09-22 6:39 UTC (permalink / raw) To: Sumit Garg Cc: linux-kernel, op-tee, Jerome Forissier, stable, Masami Ichikawa On Mon, Sep 22, 2025 at 6:11 AM Sumit Garg <sumit.garg@kernel.org> wrote: > > On Fri, Sep 19, 2025 at 02:40:16PM +0200, Jens Wiklander wrote: > > In register_shm_helper(), fix incorrect error handling for a call to > > iov_iter_extract_pages(). A case is missing for when > > iov_iter_extract_pages() only got some pages and return a number larger > > than 0, but not the requested amount. > > > > This fixes a possible NULL pointer dereference following a bad input from > > ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped. > > > > Cc: stable@vger.kernel.org > > Reported-by: Masami Ichikawa <masami256@gmail.com> > > Closes: https://lore.kernel.org/op-tee/CACOXgS-Bo2W72Nj1_44c7bntyNYOavnTjJAvUbEiQfq=u9W+-g@mail.gmail.com/ > > Fixes: 7bdee4157591 ("tee: Use iov_iter to better support shared buffer registration") > > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> > > --- > > drivers/tee/tee_shm.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > > index daf6e5cfd59a..6ed7d030f4ed 100644 > > --- a/drivers/tee/tee_shm.c > > +++ b/drivers/tee/tee_shm.c > > @@ -316,7 +316,16 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, > > > > len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0, > > &off); > > - if (unlikely(len <= 0)) { > > + if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { > > + if (len > 0) { > > + /* > > + * If we only got a few pages, update to release > > + * the correct amount below. > > + */ > > + shm->num_pages = len / PAGE_SIZE; > > + ret = ERR_PTR(-ENOMEM); > > + goto err_put_shm_pages; > > + } > > ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); > > goto err_free_shm_pages; > > } > > Rather than operating directly on "len" without checking for error code > first doesn't seems appropriate to me. How about following diff instead? Sure, works for me. > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index daf6e5cfd59a..cb52bc51943e 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -319,6 +319,14 @@ register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags, > if (unlikely(len <= 0)) { > ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); > goto err_free_shm_pages; > + } else if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) { > + /* > + * If we only got a few pages, update to release the correct > + * amount below. > + */ > + shm->num_pages = len / PAGE_SIZE; > + ret = ERR_PTR(-ENOMEM); > + goto err_put_shm_pages; > } > > /* Thanks, Jens > > -Sumit > > > -- > > 2.43.0 > > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-09-22 6:39 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-09-19 12:40 [PATCH] tee: fix register_shm_helper() Jens Wiklander 2025-09-21 6:14 ` Masami Ichikawa 2025-09-22 4:11 ` Sumit Garg 2025-09-22 6:39 ` Jens Wiklander
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