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The NBD spec says an attempt to NBD_CMD_TRIM on a read-only export should fail with EPERM, as a trim has the potential to change disk contents, but we were relying on the block layer to catch that for us, which might not always give the right error (and even if it does, it does not let us pass back a sane message for structured replies). The NBD spec says an attempt to NBD_CMD_WRITE_ZEROES out of bounds should fail with ENOSPC, not EINVAL. Our check for u64 offset + u32 length wraparound up front is pointless; nothing uses offset until after the second round of sanity checks, and we can just as easily ensure there is no wraparound by checking whether offset is in bounds (since a disk size cannot exceed off_t which is 63 bits, adding a 32-bit number for a valid offset can't overflow). Bonus: dropping the up-front check lets us keep the connection alive after NBD_CMD_WRITE, whereas before we would drop the connection (of course, any client sending a packet that would trigger the failure is already buggy, so it's also okay to drop the connection, but better quality-of-implementation never hurts). Solve all of these issues by some code motion and improved request validation. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20171115213557.3548-1-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> |
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| client.c | ||
| common.c | ||
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| nbd-internal.h | ||
| server.c | ||
| trace-events | ||