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drivers/fpga: use standard array-copy function

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dfl.c utilizes memdup_user() and array_size() to copy a userspace array.
array_size() will likely never trigger thanks to the preceding check.
Nevertheless, in the theoretical event that it would, it would return
SIZE_MAX to memdup_user(), resulting in an attempt to allocate huge
amounts of memory.

string.h from the core-api now provides memdup_array_user() which also
performs an overflow check and returns an error-pointer with -EOVERFLOW
to the caller.
As an additional advantage it standardizes how userspace-arrays are
being copied and, thus, makes it more obvious to readers that an array
is being copied.

Replace memdup_user() with memdup_array_user().

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/20231114111901.19380-2-pstanner@redhat.com
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
This commit is contained in:
Philipp Stanner 2023-11-14 12:19:02 +01:00 committed by Xu Yilun
parent b85ea95d08
commit 5496fb8eed
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GPG Key ID: FCB70381A4A08CDA
1 changed files with 2 additions and 2 deletions
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drivers/fpga/dfl.c
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@ -2008,8 +2008,8 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
(hdr.start + hdr.count < hdr.start))
return -EINVAL;
fds = memdup_user((void __user *)(arg + sizeof(hdr)),
array_size(hdr.count, sizeof(s32)));
fds = memdup_array_user((void __user *)(arg + sizeof(hdr)),
hdr.count, sizeof(s32));
if (IS_ERR(fds))
return PTR_ERR(fds);