diff mbox series

Fix null pointer dereference in vector_user_bpf

Message ID 20200610034314.9290-1-gaurav1086@gmail.com
State Superseded
Headers show
Series Fix null pointer dereference in vector_user_bpf | expand

Commit Message

Gaurav Singh June 10, 2020, 3:43 a.m. UTC 
Signed-off-by: Gaurav Singh <gaurav1086@gmail.com>

The bpf_prog is being checked for !NULL after uml_kmalloc but
later its used directly for example: 
bpf_prog->filter = bpf and is also later returned upon success.
Fix this, do a NULL check and return right away.

---
 arch/um/drivers/vector_user.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

gregkh@linuxfoundation.org June 10, 2020, 5:53 a.m. UTC | #1 
On Tue, Jun 09, 2020 at 11:43:00PM -0400, Gaurav Singh wrote:
> Signed-off-by: Gaurav Singh <gaurav1086@gmail.com>
> 
> The bpf_prog is being checked for !NULL after uml_kmalloc but
> later its used directly for example: 
> bpf_prog->filter = bpf and is also later returned upon success.
> Fix this, do a NULL check and return right away.
> 
> ---
>  arch/um/drivers/vector_user.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

No signed-off-by?
diff mbox series

Patch

diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c
index aa28e9eecb7b..71d043ae306f 100644
--- a/arch/um/drivers/vector_user.c
+++ b/arch/um/drivers/vector_user.c
@@ -730,10 +730,12 @@  void *uml_vector_user_bpf(char *filename)
 		return false;
 	}
 	bpf_prog = uml_kmalloc(sizeof(struct sock_fprog), UM_GFP_KERNEL);
-	if (bpf_prog != NULL) {
-		bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter);
-		bpf_prog->filter = NULL;
+	if (bpf_prog == NULL) {
+		printk(KERN_ERR "Failed to allocate bpf prog buffer");
+		return NULL;
 	}
+	bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter);
+	bpf_prog->filter = NULL;
 	ffd = os_open_file(filename, of_read(OPENFLAGS()), 0);
 	if (ffd < 0) {
 		printk(KERN_ERR "Error %d opening bpf file", -errno);