[PATCH 4.9 068/177] infiniband/uverbs: Fix integer overflows

From: Greg Kroah-Hartman
Date: Fri Mar 23 2018 - 07:27:41 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vlad Tsyrklevich <vlad@xxxxxxxxxxxxxxx>


[ Upstream commit 4f7f4dcfff2c19debbcdbcc861c325610a15e0c5 ]

The 'num_sge' variable is verfied to be smaller than the 'sge_count'
variable; however, since both are user-controlled it's possible to cause
an integer overflow for the kmalloc multiply on 32-bit platforms
(num_sge and sge_count are both defined u32). By crafting an input that
causes a smaller-than-expected allocation it's possible to write
controlled data out-of-bounds.

Signed-off-by: Vlad Tsyrklevich <vlad@xxxxxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/core/uverbs_cmd.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2491,9 +2491,13 @@ ssize_t ib_uverbs_destroy_qp(struct ib_u

static void *alloc_wr(size_t wr_size, __u32 num_sge)
{
+ if (num_sge >= (U32_MAX - ALIGN(wr_size, sizeof (struct ib_sge))) /
+ sizeof (struct ib_sge))
+ return NULL;
+
return kmalloc(ALIGN(wr_size, sizeof (struct ib_sge)) +
num_sge * sizeof (struct ib_sge), GFP_KERNEL);
-};
+}

ssize_t ib_uverbs_post_send(struct ib_uverbs_file *file,
struct ib_device *ib_dev,
@@ -2719,6 +2723,13 @@ static struct ib_recv_wr *ib_uverbs_unma
ret = -EINVAL;
goto err;
}
+
+ if (user_wr->num_sge >=
+ (U32_MAX - ALIGN(sizeof *next, sizeof (struct ib_sge))) /
+ sizeof (struct ib_sge)) {
+ ret = -EINVAL;
+ goto err;
+ }

next = kmalloc(ALIGN(sizeof *next, sizeof (struct ib_sge)) +
user_wr->num_sge * sizeof (struct ib_sge),