sfc: Correct validation of peer_page_count in efx_vfdi_set_status_page()

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efx_vfdi_set_status_page() validates the peer page count by
calculating the size of a request containing that many addresses and
comparing that with the maximum valid request size (4KB).  The
calculation involves a multiplication that may overflow on a 32-bit
system.

We use kcalloc() to allocate memory to store the addresses; that also
does a multiplication and it does check for integer overflow, so any
values larger than 0x1fffffff will be rejected.  However, values in
the range [0x1fffffffc, 0x1fffffff] pass boh tests and result in an
attempt to allocate nearly 4GB on the heap.  This should be rejected
rather quickly as it's obviously impossible on a 32-bit system, and
indeed the maximum possible heap allocation is 32MB.  Still, let's
make absolutely sure by fixing the initial validation.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

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Ben Hutchings 2012-02-21 02:57:33 +00:00

parent c3cb2a8741

commit 01cb543db8

1 changed files with 6 additions and 5 deletions

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drivers/net/ethernet/sfc/siena_sriov.c

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