[PATCH] [SCSI] esas2r: fix possible buffer overflow caused by bad DMA value in esas2r_process_vda_ioctl()

Qiu-ji Chen
2024-11-07T11:36:36Z

In line 1854 of the file esas2r_ioctl.c, the function
esas2r_process_vda_ioctl() is called with the parameter vi being assigned
the value of a->vda_buffer. On line 1892, a->vda_buffer is stored in DMA
memory with the statement
a->vda_buffer = dma_alloc_coherent(&a->pcid->dev, ..., indicating that the
parameter vi passed to the function is also stored in DMA memory. This
suggests that the parameter vi could be altered at any time by malicious
hardware. If vi’s value is changed after the first conditional check
if (vi->function >= vercnt), it is likely that an array out-of-bounds
access could occur in the subsequent check
if (vi->version > esas2r_vdaioctl_versions[vi_function]), leading to
serious issues.

To fix this issue, we will store the value of vi->function in a local
variable to ensure that the subsequent checks remain valid.

Signed-off-by: Qiu-ji Chen <chenqiuji666@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 26780d9e12ed ("[SCSI] esas2r: ATTO Technology ExpressSAS 6G SAS/SATA RAID Adapter Driver")
---
drivers/scsi/esas2r/esas2r_vda.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/esas2r/esas2r_vda.c b/drivers/scsi/esas2r/esas2r_vda.c
index 30028e56df63..48af8c05b01d 100644
--- a/drivers/scsi/esas2r/esas2r_vda.c
+++ b/drivers/scsi/esas2r/esas2r_vda.c
@@ -70,16 +70,17 @@ bool esas2r_process_vda_ioctl(struct esas2r_adapter *a,
u32 datalen = 0;
struct atto_vda_sge *firstsg = NULL;
u8 vercnt = (u8)ARRAY_SIZE(esas2r_vdaioctl_versions);
+ u8 vi_function = vi->function;

vi->status = ATTO_STS_SUCCESS;
vi->vda_status = RS_PENDING;

- if (vi->function >= vercnt) {
+ if (vi_function >= vercnt) {
vi->status = ATTO_STS_INV_FUNC;
return false;
}

- if (vi->version > esas2r_vdaioctl_versions[vi->function]) {
+ if (vi->version > esas2r_vdaioctl_versions[vi_function]) {
vi->status = ATTO_STS_INV_VERSION;
return false;
}
@@ -89,14 +90,14 @@ bool esas2r_process_vda_ioctl(struct esas2r_adapter *a,
return false;
}

- if (vi->function != VDA_FUNC_SCSI)
+ if (vi_function != VDA_FUNC_SCSI)
clear_vda_request(rq);

- rq->vrq->scsi.function = vi->function;
+ rq->vrq->scsi.function = vi_function;
rq->interrupt_cb = esas2r_complete_vda_ioctl;
rq->interrupt_cx = vi;

- switch (vi->function) {
+ switch (vi_function) {
case VDA_FUNC_FLASH:

if (vi->cmd.flash.sub_func != VDA_FLASH_FREAD
--
2.34.1