Hello!
On 5/22/2018 9:15 PM, Kees Cook wrote:
To avoid introducing problems like those fixed in commit f7068114d45e
("sr: pass down correctly sized SCSI sense buffer"), this creates a macro
wrapper for scsi_execute() that verifies the size of the sense buffer
similar to what was done for command string sizes in commit 3756f6401c30
("exec: avoid gcc-8 warning for get_task_comm").
Another solution could be to add another argument to scsi_execute(),
but this function already takes a lot of arguments and Jens was not fond
of that approach. As there was only a pair of dynamically allocated sense
buffers, this also moves those 96 bytes onto the stack to avoid triggering
the sizeof() check.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 6 +++---
include/scsi/scsi_device.h | 12 +++++++++++-
2 files changed, 14 insertions(+), 4 deletions(-)
[...]
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 7ae177c8e399..1bb87b6c0ad2 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -426,11 +426,21 @@ extern const char *scsi_device_state_name(enum scsi_device_state);
extern int scsi_is_sdev_device(const struct device *);
extern int scsi_is_target_device(const struct device *);
extern void scsi_sanitize_inquiry_string(unsigned char *s, int len);
-extern int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
+extern int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
int data_direction, void *buffer, unsigned bufflen,
unsigned char *sense, struct scsi_sense_hdr *sshdr,
int timeout, int retries, u64 flags,
req_flags_t rq_flags, int *resid);
+/* Make sure any sense buffer is the correct size. */
+#define scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense, \
+ sshdr, timeout, retries, flags, rq_flags, resid) \
+({ \
+ BUILD_BUG_ON((sense) != NULL && \
+ sizeof(sense) != SCSI_SENSE_BUFFERSIZE); \
This would only check the size of the 'sense' pointer, no?
+ __scsi_execute(sdev, cmd, data_direction, buffer, bufflen, \
+ sense, sshdr, timeout, retries, flags, rq_flags, \
+ resid); \
+})
static inline int scsi_execute_req(struct scsi_device *sdev,
const unsigned char *cmd, int data_direction, void *buffer,
unsigned bufflen, struct scsi_sense_hdr *sshdr, int timeout,
MBR, Sergei
