Alan Somers 38b06f8ac4 fcntl: fix overflow when setting F_READAHEAD ... VOP_READ and VOP_WRITE take the seqcount in blocks in a 16-bit field. However, fcntl allows you to set the seqcount in bytes to any nonnegative 31-bit value. The result can be a 16-bit overflow, which will be sign-extended in functions like ffs_read. Fix this by sanitizing the argument in kern_fcntl. As a matter of policy, limit to IO_SEQMAX rather than INT16_MAX. Also, fifos have overloaded the f_seqcount field for a completely different purpose ever since r238936. Formalize that by using a union type. Reviewed by: cem MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D20710		2019-06-20 23:07:20 +00:00
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fifo_vnops.c	fcntl: fix overflow when setting F_READAHEAD	2019-06-20 23:07:20 +00:00