Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Tianchen Ding <> | Subject | [RFC PATCH] scsi: ses: Fix out-of-bound write at ses_enclosure_data_process() | Date | Fri, 15 Apr 2022 11:23:13 +0800 |
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Our modified KFENCE reported a memory corruption:
[ 52.584914] BUG: KFENCE: memory corruption in ses_enclosure_data_process+0x24b/0x310 [ses]
[ 52.584917] Corrupted memory at 0xffff88982de06ff0 [ 0x00 . . . . . . . . . . . . . . . ] (in kfence-#1624698): [ 52.607212] ses_enclosure_data_process+0x24b/0x310 [ses] [ 52.607215] ses_intf_add+0x444/0x542 [ses] [ 52.621369] class_interface_register+0x110/0x120 [ 52.621373] ses_init+0x13/0x1000 [ses] [ 52.621377] do_one_initcall+0x41/0x1c0 [ 52.621380] do_init_module+0x5c/0x260 [ 52.621382] __do_sys_finit_module+0xb1/0x110 [ 52.621386] do_syscall_64+0x2d/0x40 [ 52.621388] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 52.621393] kfence-#1624698 [0xffff88982de06fc0-0xffff88982de06fe0, size=33, cache=kmalloc-64] allocated by task 1033: [ 52.670344] ses_enclosure_data_process+0x2ae/0x310 [ses] [ 52.670347] ses_intf_add+0x444/0x542 [ses] [ 52.670353] class_interface_register+0x110/0x120 [ 52.688165] ses_init+0x13/0x1000 [ses] [ 52.688169] do_one_initcall+0x41/0x1c0 [ 52.688172] do_init_module+0x5c/0x260 [ 52.688174] __do_sys_finit_module+0xb1/0x110 [ 52.688177] do_syscall_64+0x2d/0x40 [ 52.688179] entry_SYSCALL_64_after_hwframe+0x44/0xa9
This is because we check desc_ptr >= buf + page7_len first but then write '\0' to desc_ptr[len+4], while this address may be out of bound.
Fixes: 21fab1d0595e ("[SCSI] ses: update enclosure data on hot add") Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> --- drivers/scsi/ses.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c index 0a1734f34587..06b991e27c84 100644 --- a/drivers/scsi/ses.c +++ b/drivers/scsi/ses.c @@ -559,11 +559,11 @@ static void ses_enclosure_data_process(struct enclosure_device *edev, struct enclosure_component *ecomp; if (desc_ptr) { - if (desc_ptr >= buf + page7_len) { + len = (desc_ptr[2] << 8) + desc_ptr[3]; + desc_ptr += 4; + if (desc_ptr + len > buf + page7_len) { desc_ptr = NULL; } else { - len = (desc_ptr[2] << 8) + desc_ptr[3]; - desc_ptr += 4; /* Add trailing zero - pushes into * reserved space */ desc_ptr[len] = '\0'; -- 2.33.0
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