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tcmu: Fix possible to/from address overflow when doing the memcpy

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For most case the sg->length equals to PAGE_SIZE, so this bug won't
be triggered. Otherwise this will crash the kernel, for example when
all segments' sg->length equal to 1K.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Xiubo Li 2017-07-12 15:51:17 +08:00 committed by Nicholas Bellinger
parent 520eccdfe1
commit c542942cb4
1 changed files with 5 additions and 6 deletions
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9
drivers/target/target_core_user.c
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@ -563,8 +563,6 @@ static int scatter_data_area(struct tcmu_dev *udev,
block_remaining);
to_offset = get_block_offset_user(udev, dbi,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
to += offset;
if (*iov_cnt != 0 &&
to_offset == iov_tail(*iov)) {
@ -575,7 +573,9 @@ static int scatter_data_area(struct tcmu_dev *udev,
(*iov)->iov_len = copy_bytes;
}
if (copy_data) {
memcpy(to, from + sg->length - sg_remaining,
offset = DATA_BLOCK_SIZE - block_remaining;
memcpy(to + offset,
from + sg->length - sg_remaining,
copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
@ -637,9 +637,8 @@ static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
from += offset;
tcmu_flush_dcache_range(from, copy_bytes);
memcpy(to + sg->length - sg_remaining, from,
memcpy(to + sg->length - sg_remaining, from + offset,
copy_bytes);
sg_remaining -= copy_bytes;